Publications

• Emergence of spatially structured populations by area-concentrated search. Chaianunporn, Thotsapol; Hovestadt, Thomas. In Ecology and Evolution, 12(12). Wiley, 2022.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{Chaianunporn_2022, author = {Chaianunporn, Thotsapol and Hovestadt, Thomas}, journal = {Ecology and Evolution}, keywords = {myown}, month = 11, number = 12, publisher = {Wiley}, title = {Emergence of spatially structured populations by area-concentrated search}, volume = 12, year = 2022 }

  %0 Journal Article %1 Chaianunporn_2022 %A Chaianunporn, Thotsapol %A Hovestadt, Thomas %D 2022 %I Wiley %J Ecology and Evolution %N 12 %R 10.1002/ece3.9528 %T Emergence of spatially structured populations by area-concentrated search %U https://doi.org/10.1002%2Fece3.9528 %V 12

• Tracking the temporal dynamics of insect defoliation by high-resolution radar satellite data. Bae, Soyeon; Müller, Jörg; Förster, Bernhard; Hilmers, Torben; Hochrein, Sophia; Jacobs, Martin; Leroy, Benjamin ML; Pretzsch, Hans; Weisser, Wolfgang W; Mitesser, Oliver. In Methods in Ecology and Evolution. Wiley Online Library, 2021.
  • [ BibTeX ]
  • [ EndNote ]
  @article{bae2021tracking, author = {Bae, Soyeon and M{\"u}ller, J{\"o}rg and F{\"o}rster, Bernhard and Hilmers, Torben and Hochrein, Sophia and Jacobs, Martin and Leroy, Benjamin ML and Pretzsch, Hans and Weisser, Wolfgang W and Mitesser, Oliver}, journal = {Methods in Ecology and Evolution}, keywords = {teegroup}, publisher = {Wiley Online Library}, title = {Tracking the temporal dynamics of insect defoliation by high-resolution radar satellite data}, year = 2021 }

  %0 Journal Article %1 bae2021tracking %A Bae, Soyeon %A Müller, Jörg %A Förster, Bernhard %A Hilmers, Torben %A Hochrein, Sophia %A Jacobs, Martin %A Leroy, Benjamin ML %A Pretzsch, Hans %A Weisser, Wolfgang W %A Mitesser, Oliver %D 2021 %I Wiley Online Library %J Methods in Ecology and Evolution %T Tracking the temporal dynamics of insect defoliation by high-resolution radar satellite data
• Women temporarily synchronize their menstrual cycles with the luminance and gravimetric cycles of the Moon. Helfrich-Förster, C.; Monecke, S.; Spiousas, I.; Hovestadt, T.; Mitesser, O.; Wehr, T.A. In Science Advances, 7(5), p. eabe1358. 2021.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{helfrichforster2021women, abstract = {Many species synchronize reproductive behavior with a particular phase of the lunar cycle to increase reproductive success. In humans, a lunar influence on reproductive behavior remains controversial, although the human menstrual cycle has a period close to that of the lunar cycle. Here, we analyzed long-term menstrual recordings of individual women with distinct methods for biological rhythm analysis. We show that women’s menstrual cycles with a period longer than 27 days were intermittently synchronous with the Moon’s luminance and/or gravimetric cycles. With age and upon exposure to artificial nocturnal light, menstrual cycles shortened and lost this synchrony. We hypothesize that in ancient times, human reproductive behavior was synchronous with the Moon but that our modern lifestyles have changed reproductive physiology and behavior.}, author = {Helfrich-Förster, C. and Monecke, S. and Spiousas, I. and Hovestadt, T. and Mitesser, O. and Wehr, T.A.}, journal = {Science Advances}, keywords = {myown}, number = 5, pages = {eabe1358}, title = {Women temporarily synchronize their menstrual cycles with the luminance and gravimetric cycles of the Moon}, volume = 7, year = 2021 }

  %0 Journal Article %1 helfrichforster2021women %A Helfrich-Förster, C. %A Monecke, S. %A Spiousas, I. %A Hovestadt, T. %A Mitesser, O. %A Wehr, T.A. %D 2021 %J Science Advances %N 5 %P eabe1358 %R 10.1126/sciadv.abe1358 %T Women temporarily synchronize their menstrual cycles with the luminance and gravimetric cycles of the Moon %U https://advances.sciencemag.org/content/7/5/eabe1358 %V 7 %X Many species synchronize reproductive behavior with a particular phase of the lunar cycle to increase reproductive success. In humans, a lunar influence on reproductive behavior remains controversial, although the human menstrual cycle has a period close to that of the lunar cycle. Here, we analyzed long-term menstrual recordings of individual women with distinct methods for biological rhythm analysis. We show that women’s menstrual cycles with a period longer than 27 days were intermittently synchronous with the Moon’s luminance and/or gravimetric cycles. With age and upon exposure to artificial nocturnal light, menstrual cycles shortened and lost this synchrony. We hypothesize that in ancient times, human reproductive behavior was synchronous with the Moon but that our modern lifestyles have changed reproductive physiology and behavior.

• Multiple host use and the dynamics of host switching in hosttextendashparasite systems. Hovestadt, Thomas; Thomas, Jeremy A.; Mitesser, Oliver; Schönrogge, Karsten. In Insect Conservation and Diversity. Wiley, 2019.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{Hovestadt_2019, author = {Hovestadt, Thomas and Thomas, Jeremy A. and Mitesser, Oliver and Schönrogge, Karsten}, journal = {Insect Conservation and Diversity}, keywords = {olivervinzenzmitesser}, month = {08}, publisher = {Wiley}, title = {Multiple host use and the dynamics of host switching in host{\textendash}parasite systems}, year = 2019 }

  %0 Journal Article %1 Hovestadt_2019 %A Hovestadt, Thomas %A Thomas, Jeremy A. %A Mitesser, Oliver %A Schönrogge, Karsten %D 2019 %I Wiley %J Insect Conservation and Diversity %R 10.1111/icad.12374 %T Multiple host use and the dynamics of host switching in hosttextendashparasite systems %U https://doi.org/10.1111%2Ficad.12374
• The Circadian Clock Improves Fitness in the Fruit Fly, Drosophila melanogaster. Horn, Melanie; Mitesser, Oliver; Hovestadt, Thomas; Yoshii, Taishi; Rieger, Dirk; Helfrich-Förster, Charlotte. In Frontiers in Physiology, 10, p. 1374. 2019.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{10.3389/fphys.2019.01374, author = {Horn, Melanie and Mitesser, Oliver and Hovestadt, Thomas and Yoshii, Taishi and Rieger, Dirk and Helfrich-Förster, Charlotte}, journal = {Frontiers in Physiology}, keywords = {olivervinzenzmitesser}, pages = 1374, title = {The Circadian Clock Improves Fitness in the Fruit Fly, Drosophila melanogaster}, volume = 10, year = 2019 }

  %0 Journal Article %1 10.3389/fphys.2019.01374 %A Horn, Melanie %A Mitesser, Oliver %A Hovestadt, Thomas %A Yoshii, Taishi %A Rieger, Dirk %A Helfrich-Förster, Charlotte %D 2019 %J Frontiers in Physiology %P 1374 %R 10.3389/fphys.2019.01374 %T The Circadian Clock Improves Fitness in the Fruit Fly, Drosophila melanogaster %U https://www.frontiersin.org/article/10.3389/fphys.2019.01374 %V 10
• Habitat loss and fragmentation increase realized predatortextendashprey body size ratios. Hillaert, Jasmijn; Vandegehuchte, Martijn L.; Hovestadt, Thomas; Bonte, Dries. In Functional Ecology, 34(2), M. Spasojevic (ed.), pp. 534–544. Wiley, 2019.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{Hillaert_2019, author = {Hillaert, Jasmijn and Vandegehuchte, Martijn L. and Hovestadt, Thomas and Bonte, Dries}, editor = {Spasojevic, Marko}, journal = {Functional Ecology}, keywords = {myown}, month = 11, number = 2, pages = {534–544}, publisher = {Wiley}, title = {Habitat loss and fragmentation increase realized predator{\textendash}prey body size ratios}, volume = 34, year = 2019 }

  %0 Journal Article %1 Hillaert_2019 %A Hillaert, Jasmijn %A Vandegehuchte, Martijn L. %A Hovestadt, Thomas %A Bonte, Dries %D 2019 %E Spasojevic, Marko %I Wiley %J Functional Ecology %N 2 %P 534--544 %R 10.1111/1365-2435.13472 %T Habitat loss and fragmentation increase realized predatortextendashprey body size ratios %U https://doi.org/10.1111%2F1365-2435.13472 %V 34
• Dispersal evolution in metacommunities of tri-trophic systems. Chaianunporn, T.; Hovestadt, T. In Ecological Modelling, 395, pp. 28–38. 2019.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{chaianunporn2019dispersal, author = {Chaianunporn, T. and Hovestadt, T.}, journal = {Ecological Modelling}, keywords = {teegroup}, pages = {28-38}, title = {Dispersal evolution in metacommunities of tri-trophic systems}, volume = 395, year = 2019 }

  %0 Journal Article %1 chaianunporn2019dispersal %A Chaianunporn, T. %A Hovestadt, T. %D 2019 %J Ecological Modelling %P 28-38 %R 10.1016/j.ecolmodel.2019.01.012 %T Dispersal evolution in metacommunities of tri-trophic systems %U http://www.sciencedirect.com/science/article/pii/S0304380019300262 %V 395

• Explaining the variability in the response of annual eusocial insects to mass-flowering events. Hovestadt, Thomas; Mitesser, Oliver; Poethke, Achim; Holzschuh, Andrea. In Journal of Animal Ecology. 2018.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{doi:10.1111/1365-2656.12908, abstract = {Abstract Empirical studies of annual eusocial insects in agricultural landscapes report contrasting findings with regard to colony responses to mass-flowering of crops such as oilseed rape. In particular, total sexual production is often unaffected by such events, whereas worker number responds with a prominent increase. To resolve these conflicting observations, we model—using an established approach—the expected change in worker and sexual numbers in response to an increased worker productivity induced by mass-flowering events at different times of the season. We find that the predicted response pattern is mainly shaped by the degree to which individual worker productivity is reduced by an increasing number of workers in the colony. Different environmental conditions and colony characteristics result in different levels of interference of workers, for example, during foraging or nest construction. Reduction in individual productivity is low, when worker interference is negligible (“weak limitation”) and high when an increasing number of workers substantially decreases per-capita efficiency (“strong limitation”). For weak limitation, any mass-flowering event that ends before the production of sexuals starts has a strong multiplicative impact on both worker and sexual numbers. The magnitude of the effect is quite independent of the precise timing of such an event. After the onset of sexual production, mass-flowering has a weaker effect, as the added resource supply is only linearly transferred into production of additional sexuals. For colonies under strong limitation, the predicted impact of mass-flowering events is generally weaker, especially on the production of sexuals, and the timing of mass-flowering events becomes more influential: Production of sexuals profits more from late than from early mass-flowering events. Consequently, early mass-flowering events are predicted to have a prominent effect on worker numbers but a negligible one on the output of sexuals. The model presented provides a mechanistic explanation of why increased worker abundances do not necessarily translate into increased production of sexuals. The model is also applicable to other eusocial insects such as paper wasps whenever brief pulses of massive resource availability shortly elevate resource intake rates above the “normal” levels.}, author = {Hovestadt, Thomas and Mitesser, Oliver and Poethke, Achim and Holzschuh, Andrea}, journal = {Journal of Animal Ecology}, keywords = {olivervinzenzmitesser}, title = {Explaining the variability in the response of annual eusocial insects to mass-flowering events}, year = 2018 }

  %0 Journal Article %1 doi:10.1111/1365-2656.12908 %A Hovestadt, Thomas %A Mitesser, Oliver %A Poethke, Achim %A Holzschuh, Andrea %D 2018 %J Journal of Animal Ecology %R 10.1111/1365-2656.12908 %T Explaining the variability in the response of annual eusocial insects to mass-flowering events %U https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.12908 %X Abstract Empirical studies of annual eusocial insects in agricultural landscapes report contrasting findings with regard to colony responses to mass-flowering of crops such as oilseed rape. In particular, total sexual production is often unaffected by such events, whereas worker number responds with a prominent increase. To resolve these conflicting observations, we model—using an established approach—the expected change in worker and sexual numbers in response to an increased worker productivity induced by mass-flowering events at different times of the season. We find that the predicted response pattern is mainly shaped by the degree to which individual worker productivity is reduced by an increasing number of workers in the colony. Different environmental conditions and colony characteristics result in different levels of interference of workers, for example, during foraging or nest construction. Reduction in individual productivity is low, when worker interference is negligible (“weak limitation”) and high when an increasing number of workers substantially decreases per-capita efficiency (“strong limitation”). For weak limitation, any mass-flowering event that ends before the production of sexuals starts has a strong multiplicative impact on both worker and sexual numbers. The magnitude of the effect is quite independent of the precise timing of such an event. After the onset of sexual production, mass-flowering has a weaker effect, as the added resource supply is only linearly transferred into production of additional sexuals. For colonies under strong limitation, the predicted impact of mass-flowering events is generally weaker, especially on the production of sexuals, and the timing of mass-flowering events becomes more influential: Production of sexuals profits more from late than from early mass-flowering events. Consequently, early mass-flowering events are predicted to have a prominent effect on worker numbers but a negligible one on the output of sexuals. The model presented provides a mechanistic explanation of why increased worker abundances do not necessarily translate into increased production of sexuals. The model is also applicable to other eusocial insects such as paper wasps whenever brief pulses of massive resource availability shortly elevate resource intake rates above the “normal” levels.
• Suitable triggers for timing the transition from worker to sexual production in annual eusocial insects. Hovestadt, T.; Degen, T.; Mitesser, O. In Insectes Sociaux. 2018.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{Hovestadt2018, abstract = {The life cycle of many social insects living in seasonal environments is characterized by a period of (pure) investment into worker brood followed by a phase of pure allocation of resources to the production of sexuals. Researchers have invested some effort to find possible correlates (proximate triggers) of this transition but current empirical knowledge does not provide clear evidence. Utilizing an established theoretical model—modified to account for brood developmental time—we show that a strategy that switches to the production of sexuals at a particular (fixed) date may typically perform better than strategies linking the transition to the status of the colony in terms of attributes like worker or brood number, or the colony's age. Our results provide rationale why the search for cues triggering the transition in investment has been inconclusive at best and suggests a number of experiments and observations that allow validating our arguments.}, author = {Hovestadt, T. and Degen, T. and Mitesser, O.}, journal = {Insectes Sociaux}, keywords = {olivervinzenzmitesser}, month = {08}, title = {Suitable triggers for timing the transition from worker to sexual production in annual eusocial insects}, year = 2018 }

  %0 Journal Article %1 Hovestadt2018 %A Hovestadt, T. %A Degen, T. %A Mitesser, O. %D 2018 %J Insectes Sociaux %R 10.1007/s00040-018-0652-5 %T Suitable triggers for timing the transition from worker to sexual production in annual eusocial insects %U https://doi.org/10.1007/s00040-018-0652-5 %X The life cycle of many social insects living in seasonal environments is characterized by a period of (pure) investment into worker brood followed by a phase of pure allocation of resources to the production of sexuals. Researchers have invested some effort to find possible correlates (proximate triggers) of this transition but current empirical knowledge does not provide clear evidence. Utilizing an established theoretical model---modified to account for brood developmental time---we show that a strategy that switches to the production of sexuals at a particular (fixed) date may typically perform better than strategies linking the transition to the status of the colony in terms of attributes like worker or brood number, or the colony's age. Our results provide rationale why the search for cues triggering the transition in investment has been inconclusive at best and suggests a number of experiments and observations that allow validating our arguments.
• Size-dependent movement explains why bigger is better in fragmented landscapes. Hillaert, Jasmijn; Hovestadt, Thomas; Vandegehuchte, Martijn L.; Bonte, Dries. In Ecology and Evolution, 8, pp. 10754–10767. 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hillaert2018sizedependent, abstract = {Body size is a fundamental trait known to allometrically scale with metabolic rate and therefore a key determinant of individual development, life history, and consequently fitness. In spatially structured environments, movement is an equally important driver of fitness. Because movement is tightly coupled with body size, we expect habitat fragmentation to induce a strong selection pressure on size variation across and within species. Changes in body size distributions are then, in turn, expected to alter food web dynamics. However, no consensus has been reached on how spatial isolation and resource growth affect consumer body size distributions. Our aim was to investigate how these two factors shape the body size distribution of consumers under scenarios of size‐dependent and size‐independent consumer movement by applying a mechanistic, individual‐based resource–consumer model. We also assessed the consequences of altered body size distributions for important ecosystem traits such as resource abundance and consumer stability. Finally, we determined those factors that explain most variation in size distributions. We demonstrate that decreasing connectivity and resource growth select for communities (or populations) consisting of larger species (or individuals) due to strong selection for the ability to move over longer distances if the movement is size‐dependent. When including size‐dependent movement, intermediate levels of connectivity result in increases in local size diversity. Due to this elevated functional diversity, resource uptake is maximized at the metapopulation or metacommunity level. At these intermediate levels of connectivity, size‐dependent movement explains most of the observed variation in size distributions. Interestingly, local and spatial stability of consumer biomass is lowest when isolation and resource growth are high. Finally, we highlight that size‐dependent movement is of vital importance for the survival of populations or communities within highly fragmented landscapes. Our results demonstrate that considering size‐dependent movement is essential to understand how habitat fragmentation and resource growth shape body size distributions—and the resulting metapopulation or metacommunity dynamics—of consumers.}, author = {Hillaert, Jasmijn and Hovestadt, Thomas and Vandegehuchte, Martijn L. and Bonte, Dries}, journal = {Ecology and Evolution}, keywords = {teegroup}, pages = {10754–10767}, title = {Size-dependent movement explains why bigger is better in fragmented landscapes}, volume = 8, year = 2018 }

  %0 Journal Article %1 hillaert2018sizedependent %A Hillaert, Jasmijn %A Hovestadt, Thomas %A Vandegehuchte, Martijn L. %A Bonte, Dries %D 2018 %J Ecology and Evolution %P 10754–10767 %R https://doi.org/10.1002/ece3.4524 %T Size-dependent movement explains why bigger is better in fragmented landscapes %V 8 %X Body size is a fundamental trait known to allometrically scale with metabolic rate and therefore a key determinant of individual development, life history, and consequently fitness. In spatially structured environments, movement is an equally important driver of fitness. Because movement is tightly coupled with body size, we expect habitat fragmentation to induce a strong selection pressure on size variation across and within species. Changes in body size distributions are then, in turn, expected to alter food web dynamics. However, no consensus has been reached on how spatial isolation and resource growth affect consumer body size distributions. Our aim was to investigate how these two factors shape the body size distribution of consumers under scenarios of size‐dependent and size‐independent consumer movement by applying a mechanistic, individual‐based resource–consumer model. We also assessed the consequences of altered body size distributions for important ecosystem traits such as resource abundance and consumer stability. Finally, we determined those factors that explain most variation in size distributions. We demonstrate that decreasing connectivity and resource growth select for communities (or populations) consisting of larger species (or individuals) due to strong selection for the ability to move over longer distances if the movement is size‐dependent. When including size‐dependent movement, intermediate levels of connectivity result in increases in local size diversity. Due to this elevated functional diversity, resource uptake is maximized at the metapopulation or metacommunity level. At these intermediate levels of connectivity, size‐dependent movement explains most of the observed variation in size distributions. Interestingly, local and spatial stability of consumer biomass is lowest when isolation and resource growth are high. Finally, we highlight that size‐dependent movement is of vital importance for the survival of populations or communities within highly fragmented landscapes. Our results demonstrate that considering size‐dependent movement is essential to understand how habitat fragmentation and resource growth shape body size distributions—and the resulting metapopulation or metacommunity dynamics—of consumers.
• Information use during movement regulates how fragmentation and loss of habitat affect body size. Hillaert, Jamijn; Vandegehuchte, Martijn L.; Hovestadt, Thomas; Bonte, Dries. In Proceedings of the Royal Society of London (B), 285. 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hillaert2018information, abstract = {An individual's body size is central to its behaviour and physiology, and tightly linked to its movement ability. The spatial arrangement of resources and a consumer's capacity to locate them are therefore expected to exert strong selection on consumer body size. We investigated the evolutionary impact of both the fragmentation and loss of habitat on consumer body size and its feedback effects on resource distribution, under varying levels of information used during habitat choice. We developed a mechanistic, individual-based, spatially explicit model, including several allometric rules for key consumer traits. Our model reveals that as resources become more fragmented and scarce, informed habitat choice selects for larger body sizes while random habitat choice promotes small sizes. Information use may thus be an overlooked explanation for the observed variation in body size responses to habitat fragmentation. Moreover, we find that resources can accumulate and aggregate if information about resource abundance is incomplete. Informed movement results in stable resource–consumer dynamics and controlled resources across space. However, habitat loss and fragmentation destabilize local dynamics and disturb resource suppression by the consumer. Considering information use during movement is thus critical to understand the eco-evolutionary dynamics underlying the functioning and structuring of consumer communities.}, author = {Hillaert, Jamijn and Vandegehuchte, Martijn L. and Hovestadt, Thomas and Bonte, Dries}, journal = {Proceedings of the Royal Society of London (B)}, keywords = {dispersal}, title = {Information use during movement regulates how fragmentation and loss of habitat affect body size}, volume = 285, year = 2018 }

  %0 Journal Article %1 hillaert2018information %A Hillaert, Jamijn %A Vandegehuchte, Martijn L. %A Hovestadt, Thomas %A Bonte, Dries %D 2018 %J Proceedings of the Royal Society of London (B) %R https://doi.org/10.1098/rspb.2018.0953 %T Information use during movement regulates how fragmentation and loss of habitat affect body size %V 285 %X An individual's body size is central to its behaviour and physiology, and tightly linked to its movement ability. The spatial arrangement of resources and a consumer's capacity to locate them are therefore expected to exert strong selection on consumer body size. We investigated the evolutionary impact of both the fragmentation and loss of habitat on consumer body size and its feedback effects on resource distribution, under varying levels of information used during habitat choice. We developed a mechanistic, individual-based, spatially explicit model, including several allometric rules for key consumer traits. Our model reveals that as resources become more fragmented and scarce, informed habitat choice selects for larger body sizes while random habitat choice promotes small sizes. Information use may thus be an overlooked explanation for the observed variation in body size responses to habitat fragmentation. Moreover, we find that resources can accumulate and aggregate if information about resource abundance is incomplete. Informed movement results in stable resource–consumer dynamics and controlled resources across space. However, habitat loss and fragmentation destabilize local dynamics and disturb resource suppression by the consumer. Considering information use during movement is thus critical to understand the eco-evolutionary dynamics underlying the functioning and structuring of consumer communities.
• Eusociality outcompetes egalitarian and solitary strategies when resources are limited and reproduction is costly. Fronhofer, E. A.; Liebig, J.; Mitesser, O.; Poethke, H. J. In Ecology and Evolution. 2018.
  • [ BibTeX ]
  • [ EndNote ]
  @article{a2018eusociality, author = {Fronhofer, E. A. and Liebig, J. and Mitesser, O. and Poethke, H. J.}, journal = {Ecology and Evolution}, keywords = {olivervinzenzmitesser}, title = {Eusociality outcompetes egalitarian and solitary strategies when resources are limited and reproduction is costly}, year = 2018 }

  %0 Journal Article %1 a2018eusociality %A Fronhofer, E. A. %A Liebig, J. %A Mitesser, O. %A Poethke, H. J. %D 2018 %J Ecology and Evolution %T Eusociality outcompetes egalitarian and solitary strategies when resources are limited and reproduction is costly
• Exploratory behavior of re-orienting foragers differs from other flight patterns of honeybees. Degen, Jacqueline; Hovestadt, Thomas; Storms, Mona; Menzel, Randolf. In PLOS ONE, 13(8), pp. 1–14. Public Library of Science, 2018.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{10.1371/journal.pone.0202171, abstract = {Honeybees, Apis mellifera, perform re-orientation flights to learn about the new surroundings of the hive when their hive is transported to a new location. Since the pattern of re-orientation flights has not yet been studied, we asked whether this form of exploratory behavior differs from the well described exploratory orientation flights performed by young honeybees before they start foraging. We also investigated whether the exploratory components of re-orientation flights differ from foraging flights and if so how. We recorded re-orientation flights using harmonic radar technology and compared the patterns and flight parameters of these flights with the first exploratory orientation flights of young honeybees and foraging flights of experienced foragers. Just as exploratory orientation flights of young honeybees, re-orientation flights can be classified into short- and long-range flights, and most short-range re-orientation flights were performed under unfavorable weather conditions. This indicates that bees adapt the flight pattern of their re-orientation and orientation flights to changing weather conditions in a similar way. Unlike exploratory orientation flights, more than one sector of the landscape was explored during a long-range re-orientation flight, and significantly longer flight durations and flight distances were observed. Thus, re-orienting bees explored a larger terrain than bees performing their first exploratory orientation flight. By displacing some bees after their first re-orientation flight, we could demonstrate that a single re-orientation flight seems to be sufficient to learn the new location of the hive. The flight patterns of re-orientation flights differed clearly from those of foraging flights. Thus, re-orientation flights represent a special exploratory behavior that is triggered by a change in the location of the hive.}, author = {Degen, Jacqueline and Hovestadt, Thomas and Storms, Mona and Menzel, Randolf}, journal = {PLOS ONE}, keywords = {bees}, month = {08}, number = 8, pages = {1-14}, publisher = {Public Library of Science}, title = {Exploratory behavior of re-orienting foragers differs from other flight patterns of honeybees}, volume = 13, year = 2018 }

  %0 Journal Article %1 10.1371/journal.pone.0202171 %A Degen, Jacqueline %A Hovestadt, Thomas %A Storms, Mona %A Menzel, Randolf %D 2018 %I Public Library of Science %J PLOS ONE %N 8 %P 1-14 %R 10.1371/journal.pone.0202171 %T Exploratory behavior of re-orienting foragers differs from other flight patterns of honeybees %U https://doi.org/10.1371/journal.pone.0202171 %V 13 %X Honeybees, Apis mellifera, perform re-orientation flights to learn about the new surroundings of the hive when their hive is transported to a new location. Since the pattern of re-orientation flights has not yet been studied, we asked whether this form of exploratory behavior differs from the well described exploratory orientation flights performed by young honeybees before they start foraging. We also investigated whether the exploratory components of re-orientation flights differ from foraging flights and if so how. We recorded re-orientation flights using harmonic radar technology and compared the patterns and flight parameters of these flights with the first exploratory orientation flights of young honeybees and foraging flights of experienced foragers. Just as exploratory orientation flights of young honeybees, re-orientation flights can be classified into short- and long-range flights, and most short-range re-orientation flights were performed under unfavorable weather conditions. This indicates that bees adapt the flight pattern of their re-orientation and orientation flights to changing weather conditions in a similar way. Unlike exploratory orientation flights, more than one sector of the landscape was explored during a long-range re-orientation flight, and significantly longer flight durations and flight distances were observed. Thus, re-orienting bees explored a larger terrain than bees performing their first exploratory orientation flight. By displacing some bees after their first re-orientation flight, we could demonstrate that a single re-orientation flight seems to be sufficient to learn the new location of the hive. The flight patterns of re-orientation flights differed clearly from those of foraging flights. Thus, re-orientation flights represent a special exploratory behavior that is triggered by a change in the location of the hive.

• Transgenerational effects of mild heat in Arabidopsis thaliana show strong genotype specificity that is explained by climate at origin. Groot, Maartje P.; Kubisch, Alexander; Ouborg, N. Joop; Pagel, Jörn; Schmid, Karl J.; Vergeer, Philippine; Lampei, Christian. In New Phytologist. 2017.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{NPH:NPH14642, abstract = {* Transgenerational environmental effects can trigger strong phenotypic variation. However, it is unclear how cues from different preceding generations interact. Also, little is known about the genetic variation for these life history traits. * Here, we present the effects of grandparental and parental mild heat, and their combination, on four traits of the third-generation phenotype of 14 Arabidopsis thaliana genotypes. We tested for correlations of these effects with climate and constructed a conceptual model to identify the environmental conditions that favour the parental effect on flowering time. * We observed strong evidence for genotype-specific transgenerational effects. On average, A. thaliana accustomed to mild heat produced more seeds after two generations. Parental effects overruled grandparental effects in all traits except reproductive biomass. Flowering was generally accelerated by all transgenerational effects. Notably, the parental effect triggered earliest flowering in genotypes adapted to dry summers. Accordingly, this parental effect was favoured in the model when early summer heat terminated the growing season and environments were correlated across generations. * Our results suggest that A. thaliana can partly accustom to mild heat over two generations and genotype-specific parental effects show non-random evolutionary divergence across populations that may support climate change adaptation in the Mediterranean.}, author = {Groot, Maartje P. and Kubisch, Alexander and Ouborg, N. Joop and Pagel, Jörn and Schmid, Karl J. and Vergeer, Philippine and Lampei, Christian}, journal = {New Phytologist}, keywords = {teegroup}, title = {Transgenerational effects of mild heat in Arabidopsis thaliana show strong genotype specificity that is explained by climate at origin}, year = 2017 }

  %0 Journal Article %1 NPH:NPH14642 %A Groot, Maartje P. %A Kubisch, Alexander %A Ouborg, N. Joop %A Pagel, Jörn %A Schmid, Karl J. %A Vergeer, Philippine %A Lampei, Christian %D 2017 %J New Phytologist %R 10.1111/nph.14642 %T Transgenerational effects of mild heat in Arabidopsis thaliana show strong genotype specificity that is explained by climate at origin %U http://dx.doi.org/10.1111/nph.14642 %X * Transgenerational environmental effects can trigger strong phenotypic variation. However, it is unclear how cues from different preceding generations interact. Also, little is known about the genetic variation for these life history traits. * Here, we present the effects of grandparental and parental mild heat, and their combination, on four traits of the third-generation phenotype of 14 Arabidopsis thaliana genotypes. We tested for correlations of these effects with climate and constructed a conceptual model to identify the environmental conditions that favour the parental effect on flowering time. * We observed strong evidence for genotype-specific transgenerational effects. On average, A. thaliana accustomed to mild heat produced more seeds after two generations. Parental effects overruled grandparental effects in all traits except reproductive biomass. Flowering was generally accelerated by all transgenerational effects. Notably, the parental effect triggered earliest flowering in genotypes adapted to dry summers. Accordingly, this parental effect was favoured in the model when early summer heat terminated the growing season and environments were correlated across generations. * Our results suggest that A. thaliana can partly accustom to mild heat over two generations and genotype-specific parental effects show non-random evolutionary divergence across populations that may support climate change adaptation in the Mediterranean.
• Saving the injured: Rescue behavior in the termite-hunting ant Megaponera analis. Frank, Erik Thomas; Schmitt, Thomas; Hovestadt, Thomas; Mitesser, Oliver; Stiegler, Jonas; Linsenmair, Karl Eduard. In Science Advances, 3(4). American Association for the Advancement of Science, 2017.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{Franke1602187, abstract = {Predators of highly defensive prey likely develop cost-reducing adaptations. The ant Megaponera analis is a specialized termite predator, solely raiding termites of the subfamily Macrotermitinae (in this study, mostly colonies of Pseudocanthotermes sp.) at their foraging sites. The evolutionary arms race between termites and ants led to various defensive mechanisms in termites (for example, a caste specialized in fighting predators). Because M. analis incurs high injury/mortality risks when preying on termites, some risk-mitigating adaptations seem likely to have evolved. We show that a unique rescue behavior in M. analis, consisting of injured nestmates being carried back to the nest, reduces combat mortality. After a fight, injured ants are carried back by their nestmates; these ants have usually lost an extremity or have termites clinging to them and are able to recover within the nest. Injured ants that are forced experimentally to return without help, die in 32\% of the cases. Behavioral experiments show that two compounds, dimethyl disulfide and dimethyl trisulfide, present in the mandibular gland reservoirs, trigger the rescue behavior. A model accounting for this rescue behavior identifies the drivers favoring its evolution and estimates that rescuing enables maintenance of a 28.7\% larger colony size. Our results are the first to explore experimentally the adaptive value of this form of rescue behavior focused on injured nestmates in social insects and help us to identify evolutionary drivers responsible for this type of behavior to evolve in animals.}, author = {Frank, Erik Thomas and Schmitt, Thomas and Hovestadt, Thomas and Mitesser, Oliver and Stiegler, Jonas and Linsenmair, Karl Eduard}, journal = {Science Advances}, keywords = {rescue}, number = 4, publisher = {American Association for the Advancement of Science}, title = {Saving the injured: Rescue behavior in the termite-hunting ant Megaponera analis}, volume = 3, year = 2017 }

  %0 Journal Article %1 Franke1602187 %A Frank, Erik Thomas %A Schmitt, Thomas %A Hovestadt, Thomas %A Mitesser, Oliver %A Stiegler, Jonas %A Linsenmair, Karl Eduard %D 2017 %I American Association for the Advancement of Science %J Science Advances %N 4 %R 10.1126/sciadv.1602187 %T Saving the injured: Rescue behavior in the termite-hunting ant Megaponera analis %U http://advances.sciencemag.org/content/3/4/e1602187 %V 3 %X Predators of highly defensive prey likely develop cost-reducing adaptations. The ant Megaponera analis is a specialized termite predator, solely raiding termites of the subfamily Macrotermitinae (in this study, mostly colonies of Pseudocanthotermes sp.) at their foraging sites. The evolutionary arms race between termites and ants led to various defensive mechanisms in termites (for example, a caste specialized in fighting predators). Because M. analis incurs high injury/mortality risks when preying on termites, some risk-mitigating adaptations seem likely to have evolved. We show that a unique rescue behavior in M. analis, consisting of injured nestmates being carried back to the nest, reduces combat mortality. After a fight, injured ants are carried back by their nestmates; these ants have usually lost an extremity or have termites clinging to them and are able to recover within the nest. Injured ants that are forced experimentally to return without help, die in 32% of the cases. Behavioral experiments show that two compounds, dimethyl disulfide and dimethyl trisulfide, present in the mandibular gland reservoirs, trigger the rescue behavior. A model accounting for this rescue behavior identifies the drivers favoring its evolution and estimates that rescuing enables maintenance of a 28.7% larger colony size. Our results are the first to explore experimentally the adaptive value of this form of rescue behavior focused on injured nestmates in social insects and help us to identify evolutionary drivers responsible for this type of behavior to evolve in animals.
• Altered sex-specific mortality and female mating success: ecological effects and evolutionary responses. Degen, Tobias; Hovestadt, Thomas; Mitesser, Oliver; Hölker, Franz. In Ecosphere, 8(5), p. e01820-n/a. 2017.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{ECS2:ECS21820, author = {Degen, Tobias and Hovestadt, Thomas and Mitesser, Oliver and Hölker, Franz}, journal = {Ecosphere}, keywords = {asynchrony}, note = {e01820}, number = 5, pages = {e01820–n/a}, title = {Altered sex-specific mortality and female mating success: ecological effects and evolutionary responses}, volume = 8, year = 2017 }

  %0 Journal Article %1 ECS2:ECS21820 %A Degen, Tobias %A Hovestadt, Thomas %A Mitesser, Oliver %A Hölker, Franz %D 2017 %J Ecosphere %N 5 %P e01820--n/a %R 10.1002/ecs2.1820 %T Altered sex-specific mortality and female mating success: ecological effects and evolutionary responses %U http://dx.doi.org/10.1002/ecs2.1820 %V 8
• Consequences of the genetic threshold model for observing partial migration under climate change scenarios. Cobben, Marleen M. P.; van Noordwijk, Arie J. In Ecology and Evolution, p. n/a-n/a. 2017.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{ECE3:ECE33357, abstract = {Migration is a widespread phenomenon across the animal kingdom as a response to seasonality in environmental conditions. Partially migratory populations are populations that consist of both migratory and residential individuals. Such populations are very common, yet their stability has long been debated. The inheritance of migratory activity is currently best described by the threshold model of quantitative genetics. The inclusion of such a genetic threshold model for migratory behavior leads to a stable zone in time and space of partially migratory populations under a wide range of demographic parameter values, when assuming stable environmental conditions and unlimited genetic diversity. Migratory species are expected to be particularly sensitive to global warming, as arrival at the breeding grounds might be increasingly mistimed as a result of the uncoupling of long-used cues and actual environmental conditions, with decreasing reproduction as a consequence. Here, we investigate the consequences for migratory behavior and the stability of partially migratory populations under five climate change scenarios and the assumption of a genetic threshold value for migratory behavior in an individual-based model. The results show a spatially and temporally stable zone of partially migratory populations after different lengths of time in all scenarios. In the scenarios in which the species expands its range from a particular set of starting populations, the genetic diversity and location at initialization determine the species’ colonization speed across the zone of partial migration and therefore across the entire landscape. Abruptly changing environmental conditions after model initialization never caused a qualitative change in phenotype distributions, or complete extinction. This suggests that climate change-induced shifts in species’ ranges as well as changes in survival probabilities and reproductive success can be met with flexibility in migratory behavior at the species level, which will reduce the risk of extinction.}, author = {Cobben, Marleen M. P. and van Noordwijk, Arie J.}, journal = {Ecology and Evolution}, keywords = {teegroup}, pages = {n/a–n/a}, title = {Consequences of the genetic threshold model for observing partial migration under climate change scenarios}, year = 2017 }

  %0 Journal Article %1 ECE3:ECE33357 %A Cobben, Marleen M. P. %A van Noordwijk, Arie J. %D 2017 %J Ecology and Evolution %P n/a--n/a %R 10.1002/ece3.3357 %T Consequences of the genetic threshold model for observing partial migration under climate change scenarios %U http://dx.doi.org/10.1002/ece3.3357 %X Migration is a widespread phenomenon across the animal kingdom as a response to seasonality in environmental conditions. Partially migratory populations are populations that consist of both migratory and residential individuals. Such populations are very common, yet their stability has long been debated. The inheritance of migratory activity is currently best described by the threshold model of quantitative genetics. The inclusion of such a genetic threshold model for migratory behavior leads to a stable zone in time and space of partially migratory populations under a wide range of demographic parameter values, when assuming stable environmental conditions and unlimited genetic diversity. Migratory species are expected to be particularly sensitive to global warming, as arrival at the breeding grounds might be increasingly mistimed as a result of the uncoupling of long-used cues and actual environmental conditions, with decreasing reproduction as a consequence. Here, we investigate the consequences for migratory behavior and the stability of partially migratory populations under five climate change scenarios and the assumption of a genetic threshold value for migratory behavior in an individual-based model. The results show a spatially and temporally stable zone of partially migratory populations after different lengths of time in all scenarios. In the scenarios in which the species expands its range from a particular set of starting populations, the genetic diversity and location at initialization determine the species’ colonization speed across the zone of partial migration and therefore across the entire landscape. Abruptly changing environmental conditions after model initialization never caused a qualitative change in phenotype distributions, or complete extinction. This suggests that climate change-induced shifts in species’ ranges as well as changes in survival probabilities and reproductive success can be met with flexibility in migratory behavior at the species level, which will reduce the risk of extinction.
• Evolving mutation rate advances the invasion speed of a sexual species. Cobben, Marleen M. P.; Mitesser, Oliver; Kubisch, Alexander. In BMC Evolutionary Biology, 17(150), pp. 1–10. 2017.
  • [ BibTeX ]
  • [ EndNote ]
  @article{cobben2017evolving, abstract = {Background: Many species are shifting their ranges in response to global climate change. Range expansions are known to have profound effects on the genetic composition of populations. The evolution of dispersal during range expansion increases invasion speed, provided that a species can adapt sufficiently fast to novel local conditions. Genetic diversity at the expanding range border is however depleted due to iterated founder effects. The surprising ability of colonizing species to adapt to novel conditions while being subjected to genetic bottlenecks is termed ‘the genetic paradox of invasive species’. Mutational processes have been argued to provide an explanation for this paradox. Mutation rates can evolve, under conditions that favor an increased rate of adaptation, by hitchhiking on beneficial mutations through induced linkage disequilibrium. Here we argue that spatial sorting, iterated founder events, and population structure benefit the build-up and maintenance of such linkage disequilibrium. We investigate if the evolution of mutation rates could play a role in explaining the ‘genetic paradox of invasive species’ for a sexually reproducing species colonizing a landscape of gradually changing conditions. Results: We use an individual-based model to show the evolutionary increase of mutation rates in sexual populations during range expansion, in coevolution with the dispersal probability. The observed evolution of mutation rate is adaptive and clearly advances invasion speed both through its effect on the evolution of dispersal probability, and the evolution of local adaptation. This also occurs under a variable temperature gradient, and under the assumption of 90% lethal mutations. Conclusions: In this study we show novel consequences of the particular genetic properties of populations under spatial disequilibrium, i.e. the coevolution of dispersal probability and mutation rate, even in a sexual species and under realistic spatial gradients, resulting in faster invasions. The evolution of mutation rates can therefore be added to the list of possible explanations for the ‘genetic paradox of invasive species’. We conclude that range expansions and the evolution of mutation rates are in a positive feedback loop, with possibly far-reaching ecological consequences concerning invasiveness and the adaptability of species to novel environmental conditions.}, author = {Cobben, Marleen M. P. and Mitesser, Oliver and Kubisch, Alexander}, journal = {BMC Evolutionary Biology}, keywords = {olivervinzenzmitesser}, month = {06}, number = 150, pages = {1-10}, title = {Evolving mutation rate advances the invasion speed of a sexual species}, volume = 17, year = 2017 }

  %0 Journal Article %1 cobben2017evolving %A Cobben, Marleen M. P. %A Mitesser, Oliver %A Kubisch, Alexander %D 2017 %J BMC Evolutionary Biology %N 150 %P 1-10 %R 10.1186/s12862-017-0998-8 %T Evolving mutation rate advances the invasion speed of a sexual species %V 17 %X Background: Many species are shifting their ranges in response to global climate change. Range expansions are known to have profound effects on the genetic composition of populations. The evolution of dispersal during range expansion increases invasion speed, provided that a species can adapt sufficiently fast to novel local conditions. Genetic diversity at the expanding range border is however depleted due to iterated founder effects. The surprising ability of colonizing species to adapt to novel conditions while being subjected to genetic bottlenecks is termed ‘the genetic paradox of invasive species’. Mutational processes have been argued to provide an explanation for this paradox. Mutation rates can evolve, under conditions that favor an increased rate of adaptation, by hitchhiking on beneficial mutations through induced linkage disequilibrium. Here we argue that spatial sorting, iterated founder events, and population structure benefit the build-up and maintenance of such linkage disequilibrium. We investigate if the evolution of mutation rates could play a role in explaining the ‘genetic paradox of invasive species’ for a sexually reproducing species colonizing a landscape of gradually changing conditions. Results: We use an individual-based model to show the evolutionary increase of mutation rates in sexual populations during range expansion, in coevolution with the dispersal probability. The observed evolution of mutation rate is adaptive and clearly advances invasion speed both through its effect on the evolution of dispersal probability, and the evolution of local adaptation. This also occurs under a variable temperature gradient, and under the assumption of 90% lethal mutations. Conclusions: In this study we show novel consequences of the particular genetic properties of populations under spatial disequilibrium, i.e. the coevolution of dispersal probability and mutation rate, even in a sexual species and under realistic spatial gradients, resulting in faster invasions. The evolution of mutation rates can therefore be added to the list of possible explanations for the ‘genetic paradox of invasive species’. We conclude that range expansions and the evolution of mutation rates are in a positive feedback loop, with possibly far-reaching ecological consequences concerning invasiveness and the adaptability of species to novel environmental conditions.
• Mating timing, dispersal and local adaptation in patchy environments. Lakovic, Milica; Mitesser, Oliver; Hovestadt, Thomas. In Oikos. Blackwell Publishing Ltd, 2017.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{OIK:OIK4369, author = {Lakovic, Milica and Mitesser, Oliver and Hovestadt, Thomas}, journal = {Oikos}, keywords = {olivervinzenzmitesser}, publisher = {Blackwell Publishing Ltd}, title = {Mating timing, dispersal and local adaptation in patchy environments}, year = 2017 }

  %0 Journal Article %1 OIK:OIK4369 %A Lakovic, Milica %A Mitesser, Oliver %A Hovestadt, Thomas %D 2017 %I Blackwell Publishing Ltd %J Oikos %R 10.1111/oik.04369 %T Mating timing, dispersal and local adaptation in patchy environments %U http://dx.doi.org/10.1111/oik.04369

• The downward spiral: eco-evolutionary feedback loops lead to the emergence of ‘elastic’ ranges. Kubisch, Alexander; Winter, Anna-Marie; Fronhofer, Emanuel A. In Ecography, 39(3), pp. 261–269. 2016.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{kubisch_downward_2016, abstract = {In times of severe environmental changes and resulting shifts in the geographical distribution of animal and plant species it is crucial to unravel the mechanisms responsible for the dynamics of species’ ranges. Without such a mechanistic understanding, reliable projections of future species distributions are difficult to derive. Species’ ranges may be highly dynamic. One particularly interesting phenomenon is range contraction following a period of expansion, referred to as ‘elastic’ behaviour. It has been proposed that this phenomenon occurs in habitat gradients, which are characterized by a negative cline in selection for dispersal from the range core towards the margin, as one may find, for example, with increasing patch isolation. Using individual-based simulations and numerical analyses we show that Allee effects are an important determinant of range border elasticity. If only intra-specific processes are considered, Allee effects are even a necessary condition for ranges to exhibit elastic behavior. The eco-evolutionary interplay between dispersal evolution, Allee effects and habitat isolation leads to lower colonization probability and higher local extinction risk after range expansions, which result in an increasing amount of marginal sink patches and consequently, range contraction. We also demonstrate that the nature of the gradient is crucial for range elasticity. Gradients which do not select for lower dispersal at the margin than in the core (especially gradients in patch size, demographic stochasticity and extinction rate) do not lead to elastic range behavior. Thus, we predict that range contractions are likely to occur after periods of expansion for species living in gradients of increasing patch isolation, which suffer from Allee effects.}, author = {Kubisch, Alexander and Winter, Anna-Marie and Fronhofer, Emanuel A.}, journal = {Ecography}, keywords = {imported}, month = {03}, number = 3, pages = {261–269}, title = {The downward spiral: eco-evolutionary feedback loops lead to the emergence of ‘elastic’ ranges}, volume = 39, year = 2016 }

  %0 Journal Article %1 kubisch_downward_2016 %A Kubisch, Alexander %A Winter, Anna-Marie %A Fronhofer, Emanuel A. %D 2016 %J Ecography %N 3 %P 261--269 %R 10.1111/ecog.01701 %T The downward spiral: eco-evolutionary feedback loops lead to the emergence of ‘elastic’ ranges %U http://onlinelibrary.wiley.com/doi/10.1111/ecog.01701/abstract %V 39 %X In times of severe environmental changes and resulting shifts in the geographical distribution of animal and plant species it is crucial to unravel the mechanisms responsible for the dynamics of species’ ranges. Without such a mechanistic understanding, reliable projections of future species distributions are difficult to derive. Species’ ranges may be highly dynamic. One particularly interesting phenomenon is range contraction following a period of expansion, referred to as ‘elastic’ behaviour. It has been proposed that this phenomenon occurs in habitat gradients, which are characterized by a negative cline in selection for dispersal from the range core towards the margin, as one may find, for example, with increasing patch isolation. Using individual-based simulations and numerical analyses we show that Allee effects are an important determinant of range border elasticity. If only intra-specific processes are considered, Allee effects are even a necessary condition for ranges to exhibit elastic behavior. The eco-evolutionary interplay between dispersal evolution, Allee effects and habitat isolation leads to lower colonization probability and higher local extinction risk after range expansions, which result in an increasing amount of marginal sink patches and consequently, range contraction. We also demonstrate that the nature of the gradient is crucial for range elasticity. Gradients which do not select for lower dispersal at the margin than in the core (especially gradients in patch size, demographic stochasticity and extinction rate) do not lead to elastic range behavior. Thus, we predict that range contractions are likely to occur after periods of expansion for species living in gradients of increasing patch isolation, which suffer from Allee effects.
• Street lighting: sex-independent impacts on moth movement. Degen, Tobias; Mitesser, Oliver; Perkin, Elizabeth K.; Weiß, Nina-Sophie; Oehlert, Martin; Mattig, Emily; Hölker, Franz. In Journal of Animal Ecology, 85, pp. 1352–1360. 2016.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{degen_street_2016, abstract = {* Artificial lights have become an integral and welcome part of our urban and peri-urban environments. However, recent research has highlighted the potentially negative ecological consequences of ubiquitous artificial light. In particular, insects, especially moths, are expected to be negatively impacted by the presence of artificial lights. Previous research with light traps has shown a male-biased attraction to light in moths. * In this study, we sought to determine whether street lights could limit moth dispersal and whether there was any sex bias in attraction to light. More specifically, we aimed to determine sex-specific attraction radii for moths to street lights. * We tested these hypotheses by collecting moths for 2 years at an experimental set-up. To estimate the attraction radii, we developed a Markov model and related it to the acquired data. * Utilizing multinomial statistics, we found that attraction rates to lights in the middle of the matrix were substantially lower than predicted by the null hypothesis of equal attraction level (0·44 times). With the Markov model, we estimated that a corner light was 2·77 times more attractive than a wing light with an equivalentre attraction radius of c. 23 m around each light. We found neither sexual differences in the attraction rate nor in the attraction radius of males and females. Since we captured three times more males than females, we conclude that sex ratios are representative of operational sex ratios or of different flight activities. * These results provide evidence for street lights to limit moth dispersal, and that they seem to act equally on male and female moths. Consequently, public lighting might divide a suitable landscape into many small habitats. Therefore, it is reasonable to assume (i) that public lighting near hedges and bushes or field margins reduces the quality of these important habitat structures and (ii) that public lighting may affect moth movement between patches.}, author = {Degen, Tobias and Mitesser, Oliver and Perkin, Elizabeth K. and Weiß, Nina-Sophie and Oehlert, Martin and Mattig, Emily and Hölker, Franz}, journal = {Journal of Animal Ecology}, keywords = {landscape}, month = {06}, pages = {1352–1360}, title = {Street lighting: sex-independent impacts on moth movement}, volume = 85, year = 2016 }

  %0 Journal Article %1 degen_street_2016 %A Degen, Tobias %A Mitesser, Oliver %A Perkin, Elizabeth K. %A Weiß, Nina-Sophie %A Oehlert, Martin %A Mattig, Emily %A Hölker, Franz %D 2016 %J Journal of Animal Ecology %P 1352--1360 %R 10.1111/1365-2656.12540 %T Street lighting: sex-independent impacts on moth movement %U http://onlinelibrary.wiley.com/doi/10.1111/1365-2656.12540/abstract %V 85 %X * Artificial lights have become an integral and welcome part of our urban and peri-urban environments. However, recent research has highlighted the potentially negative ecological consequences of ubiquitous artificial light. In particular, insects, especially moths, are expected to be negatively impacted by the presence of artificial lights. Previous research with light traps has shown a male-biased attraction to light in moths. * In this study, we sought to determine whether street lights could limit moth dispersal and whether there was any sex bias in attraction to light. More specifically, we aimed to determine sex-specific attraction radii for moths to street lights. * We tested these hypotheses by collecting moths for 2 years at an experimental set-up. To estimate the attraction radii, we developed a Markov model and related it to the acquired data. * Utilizing multinomial statistics, we found that attraction rates to lights in the middle of the matrix were substantially lower than predicted by the null hypothesis of equal attraction level (0·44 times). With the Markov model, we estimated that a corner light was 2·77 times more attractive than a wing light with an equivalentre attraction radius of c. 23 m around each light. We found neither sexual differences in the attraction rate nor in the attraction radius of males and females. Since we captured three times more males than females, we conclude that sex ratios are representative of operational sex ratios or of different flight activities. * These results provide evidence for street lights to limit moth dispersal, and that they seem to act equally on male and female moths. Consequently, public lighting might divide a suitable landscape into many small habitats. Therefore, it is reasonable to assume (i) that public lighting near hedges and bushes or field margins reduces the quality of these important habitat structures and (ii) that public lighting may affect moth movement between patches.

• Evolution of dispersal distance: Maternal investment leads to bimodal dispersal kernels. Fronhofer, Emanuel A.; Joachim Poethke, Hans; Dieckmann, Ulf. In Journal of Theoretical Biology, 365, pp. 270–279. 2015.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{fronhofer_evolution_2015, abstract = {Since dispersal research has mainly focused on the evolutionary dynamics of dispersal rates, it remains unclear what shape evolutionarily stable dispersal kernels have. Yet, detailed knowledge about dispersal kernels, quantifying the statistical distribution of dispersal distances, is of pivotal importance for understanding biogeographic diversity, predicting species invasions, and explaining range shifts. We therefore examine the evolution of dispersal kernels in an individual-based model of a population of sessile organisms, such as trees or corals. Specifically, we analyze the influence of three potentially important factors on the shape of dispersal kernels: distance-dependent competition, distance-dependent dispersal costs, and maternal investment reducing an offspring׳s dispersal costs through a trade-off with maternal fecundity. We find that without maternal investment, competition and dispersal costs lead to unimodal kernels, with increasing dispersal costs reducing the kernel׳s width and tail weight. Unexpectedly, maternal investment inverts this effect: kernels become bimodal at high dispersal costs. This increases a kernel׳s width and tail weight, and thus the fraction of long-distance dispersers, at the expense of simultaneously increasing the fraction of non-dispersers. We demonstrate the qualitative robustness of our results against variations in the tested parameter combinations.}, author = {Fronhofer, Emanuel A. and Joachim Poethke, Hans and Dieckmann, Ulf}, journal = {Journal of Theoretical Biology}, keywords = {individual-based}, month = {01}, pages = {270–279}, title = {Evolution of dispersal distance: {Maternal} investment leads to bimodal dispersal kernels}, volume = 365, year = 2015 }

  %0 Journal Article %1 fronhofer_evolution_2015 %A Fronhofer, Emanuel A. %A Joachim Poethke, Hans %A Dieckmann, Ulf %D 2015 %J Journal of Theoretical Biology %P 270--279 %R 10.1016/j.jtbi.2014.10.024 %T Evolution of dispersal distance: Maternal investment leads to bimodal dispersal kernels %U http://www.sciencedirect.com/science/article/pii/S0022519314006146 %V 365 %X Since dispersal research has mainly focused on the evolutionary dynamics of dispersal rates, it remains unclear what shape evolutionarily stable dispersal kernels have. Yet, detailed knowledge about dispersal kernels, quantifying the statistical distribution of dispersal distances, is of pivotal importance for understanding biogeographic diversity, predicting species invasions, and explaining range shifts. We therefore examine the evolution of dispersal kernels in an individual-based model of a population of sessile organisms, such as trees or corals. Specifically, we analyze the influence of three potentially important factors on the shape of dispersal kernels: distance-dependent competition, distance-dependent dispersal costs, and maternal investment reducing an offspring׳s dispersal costs through a trade-off with maternal fecundity. We find that without maternal investment, competition and dispersal costs lead to unimodal kernels, with increasing dispersal costs reducing the kernel׳s width and tail weight. Unexpectedly, maternal investment inverts this effect: kernels become bimodal at high dispersal costs. This increases a kernel׳s width and tail weight, and thus the fraction of long-distance dispersers, at the expense of simultaneously increasing the fraction of non-dispersers. We demonstrate the qualitative robustness of our results against variations in the tested parameter combinations.
• Evolutionary responses to climate change in parasitic systems. Chaianunporn, Thotsapol; Hovestadt, Thomas. In Global Change Biology, 21(8), pp. 2905–2916. 2015.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{chaianunporn_evolutionary_2015, author = {Chaianunporn, Thotsapol and Hovestadt, Thomas}, journal = {Global Change Biology}, keywords = {commensalism,}, month = {08}, number = 8, pages = {2905–2916}, title = {Evolutionary responses to climate change in parasitic systems}, volume = 21, year = 2015 }

  %0 Journal Article %1 chaianunporn_evolutionary_2015 %A Chaianunporn, Thotsapol %A Hovestadt, Thomas %D 2015 %J Global Change Biology %N 8 %P 2905--2916 %R 10.1111/gcb.12944 %T Evolutionary responses to climate change in parasitic systems %U http://doi.wiley.com/10.1111/gcb.12944 %V 21
• Relationships between wild bees, hoverflies and pollination success in apple orchards with different landscape contexts: Importance of wild pollinators in apple orchards. Földesi, Rita; Kovács-Hostyánszki, Anikó; Kőrösi, Ádám; Somay, László; Elek, Zoltán; Markó, Viktor; Sárospataki, Miklós; Bakos, Réka; Varga, Ákos; Nyisztor, Katinka; Báldi, András. In Agricultural and Forest Entomology, 18, pp. 68–75. 2015.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{noauthororeditor2015relationships, author = {Földesi, Rita and Kovács-Hostyánszki, Anikó and Kőrösi, Ádám and Somay, László and Elek, Zoltán and Markó, Viktor and Sárospataki, Miklós and Bakos, Réka and Varga, Ákos and Nyisztor, Katinka and Báldi, András}, journal = {Agricultural and Forest Entomology}, keywords = {bees}, pages = {68-75}, title = {Relationships between wild bees, hoverflies and pollination success in apple orchards with different landscape contexts: Importance of wild pollinators in apple orchards}, volume = 18, year = 2015 }

  %0 Journal Article %1 noauthororeditor2015relationships %A Földesi, Rita %A Kovács-Hostyánszki, Anikó %A Kőrösi, Ádám %A Somay, László %A Elek, Zoltán %A Markó, Viktor %A Sárospataki, Miklós %A Bakos, Réka %A Varga, Ákos %A Nyisztor, Katinka %A Báldi, András %D 2015 %J Agricultural and Forest Entomology %P 68-75 %T Relationships between wild bees, hoverflies and pollination success in apple orchards with different landscape contexts: Importance of wild pollinators in apple orchards %U http://doi.wiley.com/10.1111/afe.12135 %V 18
• Coping with shorter days: Do phenology shifts constrain aphid fitness?. Joschinski, Jens; Krauss, Jochen; Hovestadt, Thomas. In PeerJ, 3, p. e1103. 2015.
  • [ BibTeX ]
  • [ EndNote ]
  @article{joschinski_coping_2015, abstract = {Climate change has the potential to alter seasonal timing and thus lead organisms to live under different day lengths than in the past. To examine possible fitness consequences of shifts in seasonal timing, we recorded life-history traits of asexual morphs of the aphid Acyrthosiphon pisum under short and long days and under two realistically fluctuating temperature regimes with means differing by 2°C. In addition we measured the population growth of aphids on their host plant Pisum sativum. We show that short days reduce fecundity and the length of the reproductive period of aphids. Nevertheless this does not translate to differences at the population level, because fitness costs only become apparent late in the individual’s life. Warm temperature shortens the development time of aphids by 0.7 days/°C, leading to faster generation times, while life span is reduced by 1.4 days/°C in high compared to low temperature regimes. However, warm temperature does not reduce the fecundity of aphids. We conclude that day length changes cause only relatively mild costs, which may not decelerate the increase in pest status due to climate change.}, author = {Joschinski, Jens and Krauss, Jochen and Hovestadt, Thomas}, journal = {PeerJ}, keywords = {Gent,}, pages = {e1103}, title = {Coping with shorter days: {Do} phenology shifts constrain aphid fitness?}, volume = 3, year = 2015 }

  %0 Journal Article %1 joschinski_coping_2015 %A Joschinski, Jens %A Krauss, Jochen %A Hovestadt, Thomas %D 2015 %J PeerJ %P e1103 %R https://dx.doi.org/10.7717/peerj.1103 %T Coping with shorter days: Do phenology shifts constrain aphid fitness? %V 3 %X Climate change has the potential to alter seasonal timing and thus lead organisms to live under different day lengths than in the past. To examine possible fitness consequences of shifts in seasonal timing, we recorded life-history traits of asexual morphs of the aphid Acyrthosiphon pisum under short and long days and under two realistically fluctuating temperature regimes with means differing by 2°C. In addition we measured the population growth of aphids on their host plant Pisum sativum. We show that short days reduce fecundity and the length of the reproductive period of aphids. Nevertheless this does not translate to differences at the population level, because fitness costs only become apparent late in the individual’s life. Warm temperature shortens the development time of aphids by 0.7 days/°C, leading to faster generation times, while life span is reduced by 1.4 days/°C in high compared to low temperature regimes. However, warm temperature does not reduce the fecundity of aphids. We conclude that day length changes cause only relatively mild costs, which may not decelerate the increase in pest status due to climate change.
• High female survival promotes evolution of protogyny and sexual conflict. Degen, Tobias; Hovestadt, Thomas; Mitesser, Oliver; Hölker, Franz. In PLoS ONE, 10(3), p. e0118354. 2015.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{degen_high_2015, abstract = {Existing models explaining the evolution of sexual dimorphism in the timing of emergence (SDT) in Lepidoptera assume equal mortality rates for males and females. The limiting assumption of equal mortality rates has the consequence that these models are only able to explain the evolution of emergence of males before females, i.e. protandry—the more common temporal sequence of emergence in Lepidoptera. The models fail, however, in providing adaptive explanations for the evolution of protogyny, where females emerge before males, but protogyny is not rare in insects. The assumption of equal mortality rates seems too restrictive for many insects, such as butterflies. To investigate the influence of unequal mortality rates on the evolution of SDT, we present a generalised version of a previously published model where we relax this assumption. We find that longer life-expectancy of females compared to males can indeed favour the evolution of protogyny as a fitness enhancing strategy. Moreover, the encounter rate between females and males and the sex-ratio are two important factors that also influence the evolution of optimal SDT. If considered independently for females and males the predicted strategies can be shown to be evolutionarily stable (ESS). Under the assumption of equal mortality rates the difference between the females’ and males’ ESS remains typically very small. However, female and male ESS may be quite dissimilar if mortality rates are different. This creates the potential for an ‘evolutionary conflict’ between females and males. Bagworm moths (Lepidoptera: Psychidae) provide an exemplary case where life-history attributes are such that protogyny should indeed be the optimal emergence strategy from the males’ and females’ perspectives: (i) Female longevity is considerably larger than that of males, (ii) encounter rates between females and males are presumably low, and (iii) females mate only once. Protogyny is indeed the general mating strategy found in the bagworm family.}, author = {Degen, Tobias and Hovestadt, Thomas and Mitesser, Oliver and Hölker, Franz}, journal = {PLoS ONE}, keywords = {Gent,}, number = 3, pages = {e0118354}, title = {High female survival promotes evolution of protogyny and sexual conflict}, volume = 10, year = 2015 }

  %0 Journal Article %1 degen_high_2015 %A Degen, Tobias %A Hovestadt, Thomas %A Mitesser, Oliver %A Hölker, Franz %D 2015 %J PLoS ONE %N 3 %P e0118354 %R 10.1371/journal.pone.0118354 %T High female survival promotes evolution of protogyny and sexual conflict %U http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4361667/ %V 10 %X Existing models explaining the evolution of sexual dimorphism in the timing of emergence (SDT) in Lepidoptera assume equal mortality rates for males and females. The limiting assumption of equal mortality rates has the consequence that these models are only able to explain the evolution of emergence of males before females, i.e. protandry—the more common temporal sequence of emergence in Lepidoptera. The models fail, however, in providing adaptive explanations for the evolution of protogyny, where females emerge before males, but protogyny is not rare in insects. The assumption of equal mortality rates seems too restrictive for many insects, such as butterflies. To investigate the influence of unequal mortality rates on the evolution of SDT, we present a generalised version of a previously published model where we relax this assumption. We find that longer life-expectancy of females compared to males can indeed favour the evolution of protogyny as a fitness enhancing strategy. Moreover, the encounter rate between females and males and the sex-ratio are two important factors that also influence the evolution of optimal SDT. If considered independently for females and males the predicted strategies can be shown to be evolutionarily stable (ESS). Under the assumption of equal mortality rates the difference between the females’ and males’ ESS remains typically very small. However, female and male ESS may be quite dissimilar if mortality rates are different. This creates the potential for an ‘evolutionary conflict’ between females and males. Bagworm moths (Lepidoptera: Psychidae) provide an exemplary case where life-history attributes are such that protogyny should indeed be the optimal emergence strategy from the males’ and females’ perspectives: (i) Female longevity is considerably larger than that of males, (ii) encounter rates between females and males are presumably low, and (iii) females mate only once. Protogyny is indeed the general mating strategy found in the bagworm family.

• Dispersal, evolution and range dynamics – a synthesis. Kubisch, Alexander; Fronhofer, Emanuel A. In Oikos, 123(1), pp. 3–4. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{kubisch_dispersal_2014, author = {Kubisch, Alexander and Fronhofer, Emanuel A.}, journal = {Oikos}, keywords = {imported}, month = {01}, number = 1, pages = {3–4}, title = {Dispersal, evolution and range dynamics – a synthesis}, volume = 123, year = 2014 }

  %0 Journal Article %1 kubisch_dispersal_2014 %A Kubisch, Alexander %A Fronhofer, Emanuel A. %D 2014 %J Oikos %N 1 %P 3--4 %R 10.1111/j.1600-0706.2013.01242.x %T Dispersal, evolution and range dynamics – a synthesis %U http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0706.2013.01242.x/abstract %V 123
• Gender-Specific Emigration Decisions Sensitive to Local Male and Female Density. Hovestadt, Thomas; Mitesser, Oliver; Poethke, Hans-Joachim. In The American Naturalist, 184(1), pp. 38–51. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{hovestadt_gender-specific_2014, author = {Hovestadt, Thomas and Mitesser, Oliver and Poethke, Hans-Joachim}, journal = {The American Naturalist}, keywords = {olivervinzenzmitesser}, month = {07}, number = 1, pages = {38–51}, title = {Gender-{Specific} {Emigration} {Decisions} {Sensitive} to {Local} {Male} and {Female} {Density}}, volume = 184, year = 2014 }

  %0 Journal Article %1 hovestadt_gender-specific_2014 %A Hovestadt, Thomas %A Mitesser, Oliver %A Poethke, Hans-Joachim %D 2014 %J The American Naturalist %N 1 %P 38--51 %R 10.1086/676524 %T Gender-Specific Emigration Decisions Sensitive to Local Male and Female Density %U http://www.jstor.org/stable/info/10.1086/676524 %V 184
• Habitat structure mediates spatial segregation and therefore coexistence. Boeye, Jeroen; Kubisch, Alexander; Bonte, Dries. In Landscape Ecology, 29(4), pp. 593–604. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{boeye_habitat_2014, abstract = {Understanding the mechanisms driving diversity in nature is an important and ongoing challenge in our changing world. To efficiently protect ecosystem diversity it is crucial to explain why and how species coexist. Over the last decades models explaining species coexistence have increased in complexity but usually don’t incorporate a detailed spatial context. However, spatial structure has been shown to affect species coexistence and habitat deterioration is one of the biggest threats to biodiversity. We therefore explore a spatially explicit two-species model and assess the effects of habitat structure on species coexistence using a wide diversity of fractal landscapes. Each species is specialized in a particular habitat type. We find that landscape structure has a major influence on the stability and constitution of a two species system and may be sufficient to explain the coexistence of two species. Well connected and highly structured habitat configurations allow spatial segregation of both species and this decreases local interspecific competition; in our model this is the most important process stabilizing coexistence.}, author = {Boeye, Jeroen and Kubisch, Alexander and Bonte, Dries}, journal = {Landscape Ecology}, keywords = {imported}, month = {03}, number = 4, pages = {593–604}, title = {Habitat structure mediates spatial segregation and therefore coexistence}, volume = 29, year = 2014 }

  %0 Journal Article %1 boeye_habitat_2014 %A Boeye, Jeroen %A Kubisch, Alexander %A Bonte, Dries %D 2014 %J Landscape Ecology %N 4 %P 593--604 %R 10.1007/s10980-014-0010-6 %T Habitat structure mediates spatial segregation and therefore coexistence %U http://link.springer.com/article/10.1007/s10980-014-0010-6 %V 29 %X Understanding the mechanisms driving diversity in nature is an important and ongoing challenge in our changing world. To efficiently protect ecosystem diversity it is crucial to explain why and how species coexist. Over the last decades models explaining species coexistence have increased in complexity but usually don’t incorporate a detailed spatial context. However, spatial structure has been shown to affect species coexistence and habitat deterioration is one of the biggest threats to biodiversity. We therefore explore a spatially explicit two-species model and assess the effects of habitat structure on species coexistence using a wide diversity of fractal landscapes. Each species is specialized in a particular habitat type. We find that landscape structure has a major influence on the stability and constitution of a two species system and may be sufficient to explain the coexistence of two species. Well connected and highly structured habitat configurations allow spatial segregation of both species and this decreases local interspecific competition; in our model this is the most important process stabilizing coexistence.
• Photographic survey of the prey-choice of European Bee-eaters (Merops apiaster Linnaeus, 1758) in Hungary at three colonies. Fuisz, Tibor István; Vas, Zoltán; Túri, Katalin; Kőrösi, Ádám. In Ornis Hungarica, 21(2), pp. 38–46. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{fuisz_photographic_2014, abstract = {Prey choice of European Bee-eaters was monitored via taking pictures of parent birds carrying prey items to their perches in front of the nests between 2011 and 2013 at three colonies in Hungary: at Pócsmegyer, Nagykarácsony and Albertirsa. All the colonies were studied in the breeding season, and prey items were identified from the digital images taken of adults carrying food for their chicks. During the three years 25 days were spent with collecting photographic data, and from the thousands of pictures taken 805 were suitable for analysis. On 775 photographs the prey item was identified at least to order level. Combining data from all the colonies hymenopterans were by far the most often consumed insects (50\%), followed by dragonflies (17\%), while beetles, orthopterans, lepidopterans and dipterans each contributed approximately 7-9\% of the consumed prey. Prey composition showed marked differences between the individual colonies, although the ratio of hymenopterans was everywhere high. Bee-eaters at Pócsmegyer, probably due to the abundance of aquatic habitats nearby on the Danube shore, consumed almost as much dragonflies as hymenopterans, and ate very few orthopterans. While at the Albertirsa colony, surrounded by agricultural fields and meadows in a more arid environment, hymenopterans dominated the prey, and orthopterans were almost as often consumed as dragonflies. Lepidopterans constituted approximately 8\% of Bee-eaters’ diet in all colonies. From an insect ecological viewpoint, our study provides valuable data on the species pool that might be at risk of predation by Bee-eaters, and enables us to roughly estimate the predation pressure on some taxa, and in certain cases even on species by these birds.}, author = {Fuisz, Tibor István and Vas, Zoltán and Túri, Katalin and Kőrösi, Ádám}, journal = {Ornis Hungarica}, keywords = {imported}, number = 2, pages = {38–46}, title = {Photographic survey of the prey-choice of {European} {Bee}-eaters ({Merops} apiaster {Linnaeus}, 1758) in {Hungary} at three colonies}, volume = 21, year = 2014 }

  %0 Journal Article %1 fuisz_photographic_2014 %A Fuisz, Tibor István %A Vas, Zoltán %A Túri, Katalin %A Kőrösi, Ádám %D 2014 %J Ornis Hungarica %N 2 %P 38--46 %R 10.2478/orhu-2014-0004 %T Photographic survey of the prey-choice of European Bee-eaters (Merops apiaster Linnaeus, 1758) in Hungary at three colonies %U http://www.degruyter.com/view/j/orhu.2013.21.issue-2/orhu-2014-0004/orhu-2014-0004.xml %V 21 %X Prey choice of European Bee-eaters was monitored via taking pictures of parent birds carrying prey items to their perches in front of the nests between 2011 and 2013 at three colonies in Hungary: at Pócsmegyer, Nagykarácsony and Albertirsa. All the colonies were studied in the breeding season, and prey items were identified from the digital images taken of adults carrying food for their chicks. During the three years 25 days were spent with collecting photographic data, and from the thousands of pictures taken 805 were suitable for analysis. On 775 photographs the prey item was identified at least to order level. Combining data from all the colonies hymenopterans were by far the most often consumed insects (50\%), followed by dragonflies (17\%), while beetles, orthopterans, lepidopterans and dipterans each contributed approximately 7-9% of the consumed prey. Prey composition showed marked differences between the individual colonies, although the ratio of hymenopterans was everywhere high. Bee-eaters at Pócsmegyer, probably due to the abundance of aquatic habitats nearby on the Danube shore, consumed almost as much dragonflies as hymenopterans, and ate very few orthopterans. While at the Albertirsa colony, surrounded by agricultural fields and meadows in a more arid environment, hymenopterans dominated the prey, and orthopterans were almost as often consumed as dragonflies. Lepidopterans constituted approximately 8% of Bee-eaters’ diet in all colonies. From an insect ecological viewpoint, our study provides valuable data on the species pool that might be at risk of predation by Bee-eaters, and enables us to roughly estimate the predation pressure on some taxa, and in certain cases even on species by these birds.
• Spatially correlated extinctions select for less emigration but larger dispersal distances in the Spider Mite Tetranychus Urticae. Fronhofer, Emanuel A.; Stelz, Jonas M.; Lutz, Eva; Poethke, Hans Joachim; Bonte, Dries. In Evolution, 68(6), pp. 1838–1844. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{fronhofer_spatially_2014, abstract = {Dispersal is a central process to almost all species on earth, as it connects spatially structured populations and thereby increases population persistence. Dispersal is subject to (rapid) evolution and local patch extinctions are an important selective force in this context. In contrast to the randomly distributed local extinctions considered in most theoretical studies, habitat fragmentation or other anthropogenic interventions will lead to spatially correlated extinction patterns. Under such conditions natural selection is thought to lead to more long-distance dispersal, but this theoretical prediction has not yet been verified empirically. We test this prediction in experimental spatially structured populations of the spider mite Tetranychus urticae and supplement these empirical results with insights from an individual-based evolutionary model. We demonstrate that the spatial correlation of local extinctions changes the entire distribution of dispersal distances (dispersal kernel) and selects for overall less emigration but more long-distance dispersal.}, author = {Fronhofer, Emanuel A. and Stelz, Jonas M. and Lutz, Eva and Poethke, Hans Joachim and Bonte, Dries}, journal = {Evolution}, keywords = {local}, month = {06}, number = 6, pages = {1838–1844}, title = {Spatially correlated extinctions select for less emigration but larger dispersal distances in the {Spider} {Mite} {Tetranychus} {Urticae}}, volume = 68, year = 2014 }

  %0 Journal Article %1 fronhofer_spatially_2014 %A Fronhofer, Emanuel A. %A Stelz, Jonas M. %A Lutz, Eva %A Poethke, Hans Joachim %A Bonte, Dries %D 2014 %J Evolution %N 6 %P 1838--1844 %R 10.1111/evo.12339 %T Spatially correlated extinctions select for less emigration but larger dispersal distances in the Spider Mite Tetranychus Urticae %U http://onlinelibrary.wiley.com/doi/10.1111/evo.12339/abstract %V 68 %X Dispersal is a central process to almost all species on earth, as it connects spatially structured populations and thereby increases population persistence. Dispersal is subject to (rapid) evolution and local patch extinctions are an important selective force in this context. In contrast to the randomly distributed local extinctions considered in most theoretical studies, habitat fragmentation or other anthropogenic interventions will lead to spatially correlated extinction patterns. Under such conditions natural selection is thought to lead to more long-distance dispersal, but this theoretical prediction has not yet been verified empirically. We test this prediction in experimental spatially structured populations of the spider mite Tetranychus urticae and supplement these empirical results with insights from an individual-based evolutionary model. We demonstrate that the spatial correlation of local extinctions changes the entire distribution of dispersal distances (dispersal kernel) and selects for overall less emigration but more long-distance dispersal.
• Specialization and phenological synchrony of plant-pollinator interactions along an altitudinal gradient. Benadi, Gita; Hovestadt, Thomas; Poethke, Hans-Joachim; Blüthgen, Nico. In Journal of Animal Ecology, 83(3), pp. 639–650. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{benadi_specialization_2014, author = {Benadi, Gita and Hovestadt, Thomas and Poethke, Hans-Joachim and Blüthgen, Nico}, journal = {Journal of Animal Ecology}, keywords = {Gent,}, month = {05}, number = 3, pages = {639–650}, title = {Specialization and phenological synchrony of plant-pollinator interactions along an altitudinal gradient}, volume = 83, year = 2014 }

  %0 Journal Article %1 benadi_specialization_2014 %A Benadi, Gita %A Hovestadt, Thomas %A Poethke, Hans-Joachim %A Blüthgen, Nico %D 2014 %J Journal of Animal Ecology %N 3 %P 639--650 %R 10.1111/1365-2656.12158 %T Specialization and phenological synchrony of plant-pollinator interactions along an altitudinal gradient %U http://doi.wiley.com/10.1111/1365-2656.12158 %V 83
• Optimal life-history strategy differs between philopatric and dispersing individuals in a metapopulation. Cotto, Olivier; Kubisch, Alexander; Ronce, Ophélie; Gardner, Associate Editor: Andy; Day, Editor: Troy. In The American Naturalist, 183(3), pp. 384–393. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{cotto_optimal_2014, abstract = {AbstractAbundant empirical evidence for dispersal syndromes contrasts with the rarity of theoretical predictions about the evolution of life-history divergence between dispersing and philopatric individuals. We use an evolutionary model to predict optimal differences in age-specific reproductive effort between dispersing and philopatric individuals inhabiting the same metapopulation. In our model, only young individuals disperse, and their lifelong reproductive decisions are potentially affected by this initial event. Juvenile survival declines as density of adults and other juveniles increases. We assume a trade-off between reproduction and survival, so that different patterns of age-specific reproductive effort lead to different patterns of aging. We find that young immigrant mothers should allocate more resources to reproduction than young philopatric mothers, but these life-history differences vanish as immigrant and philopatric individuals get older. However, whether the higher early reproductive effort of immigrants results in higher fecundity depends on the postimmigration cost on fecundity. Dispersing individuals have consequently a shorter life span. Ultimately, these life-history differences are due to the fact that young dispersing individuals most often live in recently founded populations, where competition is relaxed and juvenile survival higher, favoring larger investment in offspring production at the expense of survival.}, author = {Cotto, Olivier and Kubisch, Alexander and Ronce, Ophélie and Gardner, Associate Editor: Andy and Day, Editor: Troy}, journal = {The American Naturalist}, keywords = {imported}, number = 3, pages = {384–393}, title = {Optimal life-history strategy differs between philopatric and dispersing individuals in a metapopulation}, volume = 183, year = 2014 }

  %0 Journal Article %1 cotto_optimal_2014 %A Cotto, Olivier %A Kubisch, Alexander %A Ronce, Ophélie %A Gardner, Associate Editor: Andy %A Day, Editor: Troy %D 2014 %J The American Naturalist %N 3 %P 384--393 %R 10.1086/675064 %T Optimal life-history strategy differs between philopatric and dispersing individuals in a metapopulation %U http://www.jstor.org/stable/10.1086/675064 %V 183 %X AbstractAbundant empirical evidence for dispersal syndromes contrasts with the rarity of theoretical predictions about the evolution of life-history divergence between dispersing and philopatric individuals. We use an evolutionary model to predict optimal differences in age-specific reproductive effort between dispersing and philopatric individuals inhabiting the same metapopulation. In our model, only young individuals disperse, and their lifelong reproductive decisions are potentially affected by this initial event. Juvenile survival declines as density of adults and other juveniles increases. We assume a trade-off between reproduction and survival, so that different patterns of age-specific reproductive effort lead to different patterns of aging. We find that young immigrant mothers should allocate more resources to reproduction than young philopatric mothers, but these life-history differences vanish as immigrant and philopatric individuals get older. However, whether the higher early reproductive effort of immigrants results in higher fecundity depends on the postimmigration cost on fecundity. Dispersing individuals have consequently a shorter life span. Ultimately, these life-history differences are due to the fact that young dispersing individuals most often live in recently founded populations, where competition is relaxed and juvenile survival higher, favoring larger investment in offspring production at the expense of survival.
• Where am I and why? Synthesizing range biology and the eco-evolutionary dynamics of dispersal. Kubisch, Alexander; Holt, Robert D.; Poethke, Hans-Joachim; Fronhofer, Emanuel A. In Oikos, 123(1), pp. 5–22. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{kubisch_where_2014, abstract = {Although generations of researchers have studied the factors that limit the distributions of species, we still do not seem to understand this phenomenon comprehensively. Traditionally, species’ ranges have been seen as the consequence of abiotic conditions and local adaptation to the environment. However, during the last years it has become more and more evident that biotic factors – such as intra- and interspecific interactions or the dispersal capacity of species – and even rapidly occurring evolutionary processes can strongly influence the range of a species and its potential to spread to new habitats. Relevant eco-evolutionary forces can be found at all hierarchical levels: from landscapes to communities via populations, individuals and genes. We here use the metapopulation concept to develop a framework that allows us to synthesize this broad spectrum of different factors. Since species’ ranges are the result of a dynamic equilibrium of colonization and local extinction events, the importance of dispersal is immediately clear. We highlight the complex interrelations and feedbacks between ecological and evolutionary forces that shape dispersal and result in non-trivial and partially counter-intuitive range dynamics. Our concept synthesizes current knowledge on range biology and the eco-evolutionary dynamics of dispersal. Synthesis What factors are responsible for the dynamics of species' ranges? Answering this question has never been more important than today, in the light of rapid environmental changes. Surprisingly, the ecological and evolutionary dynamics of dispersal – which represent the driving forces behind range formation – have rarely been considered in this context. We here present a framework that closes this gap. Dispersal evolution may be responsible for highly complex and non-trivial range dynamics. In order to understand these, and possibly provide projections of future range positions, it is crucial to take the ecological and evolutionary dynamics of dispersal into account.}, author = {Kubisch, Alexander and Holt, Robert D. and Poethke, Hans-Joachim and Fronhofer, Emanuel A.}, journal = {Oikos}, keywords = {imported}, month = {01}, number = 1, pages = {5–22}, title = {Where am {I} and why? {Synthesizing} range biology and the eco-evolutionary dynamics of dispersal}, volume = 123, year = 2014 }

  %0 Journal Article %1 kubisch_where_2014 %A Kubisch, Alexander %A Holt, Robert D. %A Poethke, Hans-Joachim %A Fronhofer, Emanuel A. %D 2014 %J Oikos %N 1 %P 5--22 %R 10.1111/j.1600-0706.2013.00706.x %T Where am I and why? Synthesizing range biology and the eco-evolutionary dynamics of dispersal %U http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0706.2013.00706.x/abstract %V 123 %X Although generations of researchers have studied the factors that limit the distributions of species, we still do not seem to understand this phenomenon comprehensively. Traditionally, species’ ranges have been seen as the consequence of abiotic conditions and local adaptation to the environment. However, during the last years it has become more and more evident that biotic factors – such as intra- and interspecific interactions or the dispersal capacity of species – and even rapidly occurring evolutionary processes can strongly influence the range of a species and its potential to spread to new habitats. Relevant eco-evolutionary forces can be found at all hierarchical levels: from landscapes to communities via populations, individuals and genes. We here use the metapopulation concept to develop a framework that allows us to synthesize this broad spectrum of different factors. Since species’ ranges are the result of a dynamic equilibrium of colonization and local extinction events, the importance of dispersal is immediately clear. We highlight the complex interrelations and feedbacks between ecological and evolutionary forces that shape dispersal and result in non-trivial and partially counter-intuitive range dynamics. Our concept synthesizes current knowledge on range biology and the eco-evolutionary dynamics of dispersal. Synthesis What factors are responsible for the dynamics of species' ranges? Answering this question has never been more important than today, in the light of rapid environmental changes. Surprisingly, the ecological and evolutionary dynamics of dispersal – which represent the driving forces behind range formation – have rarely been considered in this context. We here present a framework that closes this gap. Dispersal evolution may be responsible for highly complex and non-trivial range dynamics. In order to understand these, and possibly provide projections of future range positions, it is crucial to take the ecological and evolutionary dynamics of dispersal into account.
• Effects of timing and frequency of mowing on the threatened scarce large blue butterfly – A fine-scale experiment. Kőrösi, Ádám; Szentirmai, István; Batáry, Péter; Kövér, Szilvia; Örvössy, Noémi; Peregovits, László. In Agriculture, Ecosystems & Environment, 196, pp. 24–33. 2014.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{korosi_effects_2014, abstract = {As part of a major transformation of the EU agriculture in the last few decades, traditional land-use types disappeared due to either intensification or abandonment. Grasslands are highly affected in this process and are consequently among the most threatened semi-natural habitats in Europe. However, experimental evidence is scarce on the effects of management types on biodiversity. Moreover, management types need to be feasible within the recently changed socio-economic circumstances in Hungary. We investigated the effects of timing and frequency of mowing on the abundance of the scarce large blue butterfly (Phengaris teleius), on the abundance of its host plant and on the frequency of its host ant species. In each of four study meadows, we applied four types of management: one cut per year in May, one cut per year in September, two cuts per year (May and September) and cessation of management. After three years of experimental management, we found that adult butterflies preferred plots cut once in September over plots cut twice per year and abandoned ones, while plots cut once in May were also preferred over abandoned plots. Relative host plant abundance remarkably increased in plots cut once in September. Management did not affect the occupancy pattern of Myrmica host ants. Invasive goldenrod was successfully retained by two cuts per year. To our knowledge, this is the first attempt to test management effects on the whole community module of a socially parasitic butterfly, its host plant and host ants. Based on the results, we provide recommendations on regional management of the scarce large blue's habitats.}, author = {Kőrösi, Ádám and Szentirmai, István and Batáry, Péter and Kövér, Szilvia and Örvössy, Noémi and Peregovits, László}, journal = {Agriculture, Ecosystems \& Environment}, keywords = {Habitat}, month = 10, pages = {24–33}, title = {Effects of timing and frequency of mowing on the threatened scarce large blue butterfly – {A} fine-scale experiment}, volume = 196, year = 2014 }

  %0 Journal Article %1 korosi_effects_2014 %A Kőrösi, Ádám %A Szentirmai, István %A Batáry, Péter %A Kövér, Szilvia %A Örvössy, Noémi %A Peregovits, László %D 2014 %J Agriculture, Ecosystems & Environment %P 24--33 %R 10.1016/j.agee.2014.06.019 %T Effects of timing and frequency of mowing on the threatened scarce large blue butterfly – A fine-scale experiment %U http://www.sciencedirect.com/science/article/pii/S0167880914003491 %V 196 %X As part of a major transformation of the EU agriculture in the last few decades, traditional land-use types disappeared due to either intensification or abandonment. Grasslands are highly affected in this process and are consequently among the most threatened semi-natural habitats in Europe. However, experimental evidence is scarce on the effects of management types on biodiversity. Moreover, management types need to be feasible within the recently changed socio-economic circumstances in Hungary. We investigated the effects of timing and frequency of mowing on the abundance of the scarce large blue butterfly (Phengaris teleius), on the abundance of its host plant and on the frequency of its host ant species. In each of four study meadows, we applied four types of management: one cut per year in May, one cut per year in September, two cuts per year (May and September) and cessation of management. After three years of experimental management, we found that adult butterflies preferred plots cut once in September over plots cut twice per year and abandoned ones, while plots cut once in May were also preferred over abandoned plots. Relative host plant abundance remarkably increased in plots cut once in September. Management did not affect the occupancy pattern of Myrmica host ants. Invasive goldenrod was successfully retained by two cuts per year. To our knowledge, this is the first attempt to test management effects on the whole community module of a socially parasitic butterfly, its host plant and host ants. Based on the results, we provide recommendations on regional management of the scarce large blue's habitats.

• Group tolerance, dispersal evolution, and the maintenance of polymorphism in recognition cues. Chaianunporn, T.; Hovestadt, T. In Behavioral Ecology, 25(1), pp. 191–199. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{chaianunporn_group_2013, author = {Chaianunporn, T. and Hovestadt, T.}, journal = {Behavioral Ecology}, keywords = {CLIMIT,}, month = 12, number = 1, pages = {191–199}, title = {Group tolerance, dispersal evolution, and the maintenance of polymorphism in recognition cues}, volume = 25, year = 2013 }

  %0 Journal Article %1 chaianunporn_group_2013 %A Chaianunporn, T. %A Hovestadt, T. %D 2013 %J Behavioral Ecology %N 1 %P 191--199 %R 10.1093/beheco/art104 %T Group tolerance, dispersal evolution, and the maintenance of polymorphism in recognition cues %U http://www.beheco.oxfordjournals.org/cgi/doi/10.1093/beheco/art104 %V 25
• The genetic structure of populations of Metrioptera bicolor in a spatially structured landscape: effects of dispersal barriers and geographic distance. Heidinger, Ina Monika Margret; Hein, Silke; Feldhaar, Heike; Poethke, Hans-Joachim. In Conservation Genetics, 14(2), pp. 299–311. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{heidinger_genetic_2013, abstract = {The stability and long-term survival of animal populations in fragmented landscapes largely depends on the colonisation of habitat patches and the exchange of individuals between patches. The degree of inter-patch dispersal, in turn, depends on the dispersal abilities of species and the landscape structure (i.e. the nature of the landscape matrix and habitat distribution). Here, we investigated the genetic structure of populations of Metrioptera bicolor, a wing-dimorphic bush cricket, in a spatially structured landscape with patches of suitable habitat distributed within a diverse matrix of different habitat types. Using six microsatellite markers, we assessed the effects of geographic distance and different matrix types on the extent of genetic differentiation among 24 sampling sites. We found that forest and a river running through the study area both impede inter-patch dispersal. The presence of these two matrix types was positively correlated with the extent of genetic differentiation between sites. In addition, we found a significant positive correlation between pairwise genetic and geographic distances for a subsample of sites which were separated only by arable land or settlements. For the complete data set, this correlation could not be found. This is most probably because the adverse effect of forest and river on gene flow dominates the effect of geographic distance in our limited set of patches. Our analyses clearly emphasize the differential resistance of different habitat types on dispersal and the importance of a more detailed view on matrix “quality” in metapopulation studies.}, author = {Heidinger, Ina Monika Margret and Hein, Silke and Feldhaar, Heike and Poethke, Hans-Joachim}, journal = {Conservation Genetics}, keywords = {imported}, month = {01}, number = 2, pages = {299–311}, title = {The genetic structure of populations of {Metrioptera} bicolor in a spatially structured landscape: effects of dispersal barriers and geographic distance}, volume = 14, year = 2013 }

  %0 Journal Article %1 heidinger_genetic_2013 %A Heidinger, Ina Monika Margret %A Hein, Silke %A Feldhaar, Heike %A Poethke, Hans-Joachim %D 2013 %J Conservation Genetics %N 2 %P 299--311 %R 10.1007/s10592-013-0449-z %T The genetic structure of populations of Metrioptera bicolor in a spatially structured landscape: effects of dispersal barriers and geographic distance %U http://link.springer.com/article/10.1007/s10592-013-0449-z %V 14 %X The stability and long-term survival of animal populations in fragmented landscapes largely depends on the colonisation of habitat patches and the exchange of individuals between patches. The degree of inter-patch dispersal, in turn, depends on the dispersal abilities of species and the landscape structure (i.e. the nature of the landscape matrix and habitat distribution). Here, we investigated the genetic structure of populations of Metrioptera bicolor, a wing-dimorphic bush cricket, in a spatially structured landscape with patches of suitable habitat distributed within a diverse matrix of different habitat types. Using six microsatellite markers, we assessed the effects of geographic distance and different matrix types on the extent of genetic differentiation among 24 sampling sites. We found that forest and a river running through the study area both impede inter-patch dispersal. The presence of these two matrix types was positively correlated with the extent of genetic differentiation between sites. In addition, we found a significant positive correlation between pairwise genetic and geographic distances for a subsample of sites which were separated only by arable land or settlements. For the complete data set, this correlation could not be found. This is most probably because the adverse effect of forest and river on gene flow dominates the effect of geographic distance in our limited set of patches. Our analyses clearly emphasize the differential resistance of different habitat types on dispersal and the importance of a more detailed view on matrix “quality” in metapopulation studies.
• Contrasting specialization–stability relationships in plant–animal mutualistic systems. Benadi, Gita; Blüthgen, Nico; Hovestadt, Thomas; Poethke, Hans-Joachim. In Ecological Modelling, 258, pp. 65–73. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{benadi_contrasting_2013, author = {Benadi, Gita and Blüthgen, Nico and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {Ecological Modelling}, keywords = {pollination}, month = {06}, pages = {65–73}, title = {Contrasting specialization–stability relationships in plant–animal mutualistic systems}, volume = 258, year = 2013 }

  %0 Journal Article %1 benadi_contrasting_2013 %A Benadi, Gita %A Blüthgen, Nico %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2013 %J Ecological Modelling %P 65--73 %R 10.1016/j.ecolmodel.2013.03.002 %T Contrasting specialization–stability relationships in plant–animal mutualistic systems %U http://linkinghub.elsevier.com/retrieve/pii/S0304380013001518 %V 258
• When can plant-pollinator interactions promote plant diversity?. Benadi, Gita; Blüthgen, Nico; Hovestadt, Thomas; Poethke, Hans-Joachim. In The American Naturalist, 182(2), pp. 131–146. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{benadi_when_2013, author = {Benadi, Gita and Blüthgen, Nico and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {The American Naturalist}, keywords = {pollination}, month = {08}, number = 2, pages = {131–146}, title = {When can plant-pollinator interactions promote plant diversity?}, volume = 182, year = 2013 }

  %0 Journal Article %1 benadi_when_2013 %A Benadi, Gita %A Blüthgen, Nico %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2013 %J The American Naturalist %N 2 %P 131--146 %R 10.1086/670942 %T When can plant-pollinator interactions promote plant diversity? %U http://www.jstor.org/stable/info/10.1086/670942 %V 182
• Kin competition as a major driving force for invasions. Kubisch, Alexander; Fronhofer, Emanuel A.; Poethke, Hans Joachim; Hovestadt, Thomas. In The American Naturalist, 181(5), pp. 700–706. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{kubisch_kin_2013, author = {Kubisch, Alexander and Fronhofer, Emanuel A. and Poethke, Hans Joachim and Hovestadt, Thomas}, journal = {The American Naturalist}, keywords = {dispersal}, month = {05}, number = 5, pages = {700–706}, title = {Kin competition as a major driving force for invasions}, volume = 181, year = 2013 }

  %0 Journal Article %1 kubisch_kin_2013 %A Kubisch, Alexander %A Fronhofer, Emanuel A. %A Poethke, Hans Joachim %A Hovestadt, Thomas %D 2013 %J The American Naturalist %N 5 %P 700--706 %R 10.1086/670008 %T Kin competition as a major driving force for invasions %U http://www.jstor.org/stable/info/10.1086/670008 %V 181
• From random walks to informed movement. Fronhofer, Emanuel A.; Hovestadt, Thomas; Poethke, Hans-Joachim. In Oikos, 122(6), pp. 857–866. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{fronhofer_random_2013, author = {Fronhofer, Emanuel A. and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {Oikos}, keywords = {Movement}, month = {06}, number = 6, pages = {857–866}, title = {From random walks to informed movement}, volume = 122, year = 2013 }

  %0 Journal Article %1 fronhofer_random_2013 %A Fronhofer, Emanuel A. %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2013 %J Oikos %N 6 %P 857--866 %R 10.1111/j.1600-0706.2012.21021.x %T From random walks to informed movement %U http://doi.wiley.com/10.1111/j.1600-0706.2012.21021.x %V 122
• Picky hitch-hikers: vector choice leads to directed dispersal and fat-tailed kernels in a passively dispersing mite. Fronhofer, Emanuel A.; Sperr, Ellen B.; Kreis, Anna; Ayasse, Manfred; Poethke, Hans Joachim; Tschapka, Marco. In Oikos, 122(8), pp. 1254–1264. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{fronhofer_picky_2013, abstract = {Dispersal is a central life-history trait for most animals and plants: it allows to colonize new habitats, escape from competition or avoid inbreeding. Yet, not all species are mobile enough to perform sufficient dispersal. Such passive dispersers may use more mobile animals as dispersal vectors. If multiple potential vectors are available, an active choice can allow to optimize the dispersal process and to determine the distribution of dispersal distances, i.e. an optimal dispersal kernel. We explore dispersal and vector choice in the neotropical flower mite Spadiseius calyptrogynae using a dual approach which combines experiments with an individual-based simulation model. Spadiseius calyptrogynae is found in lowland rainforests in Costa Rica. It inhabits inflorescences of the understorey palm Calyptrogyne ghiesbreghtiana and is phoretic on a number of flower visitors including bats, beetles and stingless bees. We hypothesised that the mites should optimise their dispersal kernel by actively choosing a specific mix of potential phoretic vectors. In a simple olfactometer setup we showed that the flower mites do indeed discriminate between potential vectors. Subsequently we used an individual-based model to analyse the evolutionary forces responsible for the observed patterns of vector choice. The mites combine vectors exhibiting long-distance dispersal with those allowing for more localized dispersal. This results in a fat-tailed dispersal kernel that guarantees the occasional colonization of new host plant patches (long distance) while optimizing the exploitation of clumped resources (local dispersal). Additionally, kin competition results in a preference for small vectors that transport only few individuals at a time. At the same time, these vectors lead to directed dispersal towards suitable habitat, which increases the stability of this very specialized interaction. Our findings can be applied to other phoretic systems but also to vector-based seed dispersal, for example.}, author = {Fronhofer, Emanuel A. and Sperr, Ellen B. and Kreis, Anna and Ayasse, Manfred and Poethke, Hans Joachim and Tschapka, Marco}, journal = {Oikos}, keywords = {imported}, month = {08}, number = 8, pages = {1254–1264}, title = {Picky hitch-hikers: vector choice leads to directed dispersal and fat-tailed kernels in a passively dispersing mite}, volume = 122, year = 2013 }

  %0 Journal Article %1 fronhofer_picky_2013 %A Fronhofer, Emanuel A. %A Sperr, Ellen B. %A Kreis, Anna %A Ayasse, Manfred %A Poethke, Hans Joachim %A Tschapka, Marco %D 2013 %J Oikos %N 8 %P 1254--1264 %R 10.1111/j.1600-0706.2013.00503.x %T Picky hitch-hikers: vector choice leads to directed dispersal and fat-tailed kernels in a passively dispersing mite %U http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0706.2013.00503.x/abstract %V 122 %X Dispersal is a central life-history trait for most animals and plants: it allows to colonize new habitats, escape from competition or avoid inbreeding. Yet, not all species are mobile enough to perform sufficient dispersal. Such passive dispersers may use more mobile animals as dispersal vectors. If multiple potential vectors are available, an active choice can allow to optimize the dispersal process and to determine the distribution of dispersal distances, i.e. an optimal dispersal kernel. We explore dispersal and vector choice in the neotropical flower mite Spadiseius calyptrogynae using a dual approach which combines experiments with an individual-based simulation model. Spadiseius calyptrogynae is found in lowland rainforests in Costa Rica. It inhabits inflorescences of the understorey palm Calyptrogyne ghiesbreghtiana and is phoretic on a number of flower visitors including bats, beetles and stingless bees. We hypothesised that the mites should optimise their dispersal kernel by actively choosing a specific mix of potential phoretic vectors. In a simple olfactometer setup we showed that the flower mites do indeed discriminate between potential vectors. Subsequently we used an individual-based model to analyse the evolutionary forces responsible for the observed patterns of vector choice. The mites combine vectors exhibiting long-distance dispersal with those allowing for more localized dispersal. This results in a fat-tailed dispersal kernel that guarantees the occasional colonization of new host plant patches (long distance) while optimizing the exploitation of clumped resources (local dispersal). Additionally, kin competition results in a preference for small vectors that transport only few individuals at a time. At the same time, these vectors lead to directed dispersal towards suitable habitat, which increases the stability of this very specialized interaction. Our findings can be applied to other phoretic systems but also to vector-based seed dispersal, for example.
• Prey density, value, and spatial distribution affect the efficiency of area-concentrated search. Bartoń, Kamil A.; Hovestadt, Thomas. In Journal of Theoretical Biology, 316, pp. 61–69. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{barton_prey_2013, author = {Bartoń, Kamil A. and Hovestadt, Thomas}, journal = {Journal of Theoretical Biology}, keywords = {TenLamas}, month = {01}, pages = {61–69}, title = {Prey density, value, and spatial distribution affect the efficiency of area-concentrated search}, volume = 316, year = 2013 }

  %0 Journal Article %1 barton_prey_2013 %A Bartoń, Kamil A. %A Hovestadt, Thomas %D 2013 %J Journal of Theoretical Biology %P 61--69 %R 10.1016/j.jtbi.2012.09.002 %T Prey density, value, and spatial distribution affect the efficiency of area-concentrated search %U http://linkinghub.elsevier.com/retrieve/pii/S0022519312004705 %V 316
• Predicting range shifts under global change: the balance between local adaptation and dispersal. Kubisch, Alexander; Degen, Tobias; Hovestadt, Thomas; Poethke, Hans Joachim. In Ecography, 36(8), pp. 873–882. 2013.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{kubisch_predicting_2013, author = {Kubisch, Alexander and Degen, Tobias and Hovestadt, Thomas and Poethke, Hans Joachim}, journal = {Ecography}, keywords = {dispersal}, month = {08}, number = 8, pages = {873–882}, title = {Predicting range shifts under global change: the balance between local adaptation and dispersal}, volume = 36, year = 2013 }

  %0 Journal Article %1 kubisch_predicting_2013 %A Kubisch, Alexander %A Degen, Tobias %A Hovestadt, Thomas %A Poethke, Hans Joachim %D 2013 %J Ecography %N 8 %P 873--882 %R 10.1111/j.1600-0587.2012.00062.x %T Predicting range shifts under global change: the balance between local adaptation and dispersal %U http://doi.wiley.com/10.1111/j.1600-0587.2012.00062.x %V 36

• Effects of grazing, vegetation structure and landscape complexity on grassland leafhoppers (Hemiptera: {Auchenorrhyncha}) and true bugs (Hemiptera: {Heteroptera}) in Hungary. Kőrösi, Ádám; Batáry, Péter; Orosz, András; Rédei, Dávid; Báldi, András. In Insect Conservation and Diversity, 5(1), pp. 57–66. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{korosi_effects_2012, abstract = {Abstract.  1. Agricultural intensification is a major cause of biodiversity loss in European farmlands. Grasslands are particularly important habitats for the conservation of rich insect assemblages of Central and Eastern Europe. Although regular grazing or mowing of these grasslands is required to maintain diversity, there is no information about how such management and other factors influence Hemiptera assemblages. 2. We studied leafhopper and true bug assemblages in semi-natural grasslands in three regions of the Great Hungarian Plain. We investigated how local vegetation factors and landscape complexity influence assemblages and whether they interact with management effects. 3. Seven pairs of intensively ({\textgreater}1 cow/ha) versus extensively (∼0.5 cow/ha) grazed pastures were sampled in each region by sweep-netting. 4. Sward height was the most important explanatory factor for leafhoppers (84 species, 27264 individuals), as it increased both species number and abundance, and influenced assemblage composition. The extent of grassland surrounding the sample sites negatively affected leafhoppers, whereas extensive grazing decreased abundance and influenced composition. True bug assemblages (140 species, 6656 individuals) were positively affected only by mean sward height, whereas regional differences determined the community composition of both taxa. 5. We conclude that vegetation structure is the primary factor shaping Hemiptera communities and that the various types of grasslands studied are all important habitats for the taxon. Therefore, cattle grazing in its current form is beneficial for the rich Hemiptera fauna in lowland pastures of Hungary. However, in some cases, local and landscape factors and great regional differences may confound the effects of grazing, and this must be considered in conservation planning in the future.}, author = {Kőrösi, Ádám and Batáry, Péter and Orosz, András and Rédei, Dávid and Báldi, András}, journal = {Insect Conservation and Diversity}, keywords = {landscape}, month = {02}, number = 1, pages = {57–66}, title = {Effects of grazing, vegetation structure and landscape complexity on grassland leafhoppers ({Hemiptera}: {Auchenorrhyncha}) and true bugs ({Hemiptera}: {Heteroptera}) in {Hungary}}, volume = 5, year = 2012 }

  %0 Journal Article %1 korosi_effects_2012 %A Kőrösi, Ádám %A Batáry, Péter %A Orosz, András %A Rédei, Dávid %A Báldi, András %D 2012 %J Insect Conservation and Diversity %N 1 %P 57--66 %R 10.1111/j.1752-4598.2011.00153.x %T Effects of grazing, vegetation structure and landscape complexity on grassland leafhoppers (Hemiptera: {Auchenorrhyncha}) and true bugs (Hemiptera: {Heteroptera}) in Hungary %U http://onlinelibrary.wiley.com/doi/10.1111/j.1752-4598.2011.00153.x/abstract %V 5 %X Abstract.  1. Agricultural intensification is a major cause of biodiversity loss in European farmlands. Grasslands are particularly important habitats for the conservation of rich insect assemblages of Central and Eastern Europe. Although regular grazing or mowing of these grasslands is required to maintain diversity, there is no information about how such management and other factors influence Hemiptera assemblages. 2. We studied leafhopper and true bug assemblages in semi-natural grasslands in three regions of the Great Hungarian Plain. We investigated how local vegetation factors and landscape complexity influence assemblages and whether they interact with management effects. 3. Seven pairs of intensively (\textgreater1 cow/ha) versus extensively (∼0.5 cow/ha) grazed pastures were sampled in each region by sweep-netting. 4. Sward height was the most important explanatory factor for leafhoppers (84 species, 27264 individuals), as it increased both species number and abundance, and influenced assemblage composition. The extent of grassland surrounding the sample sites negatively affected leafhoppers, whereas extensive grazing decreased abundance and influenced composition. True bug assemblages (140 species, 6656 individuals) were positively affected only by mean sward height, whereas regional differences determined the community composition of both taxa. 5. We conclude that vegetation structure is the primary factor shaping Hemiptera communities and that the various types of grasslands studied are all important habitats for the taxon. Therefore, cattle grazing in its current form is beneficial for the rich Hemiptera fauna in lowland pastures of Hungary. However, in some cases, local and landscape factors and great regional differences may confound the effects of grazing, and this must be considered in conservation planning in the future.
• Different habitat selection by two sympatric Maculinea butterflies at small spatial scale. Kőrösi, Ádám; Örvössy, Noémi; Batáry, PéTer; Harnos, Andrea; Peregovits, LáSzló. In Insect Conservation and Diversity, 5(2), pp. 118–126. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{korosi_different_2012, author = {Kőrösi, Ádám and Örvössy, Noémi and Batáry, PéTer and Harnos, Andrea and Peregovits, LáSzló}, journal = {Insect Conservation and Diversity}, keywords = {nausithous,}, month = {03}, number = 2, pages = {118–126}, title = {Different habitat selection by two sympatric {Maculinea} butterflies at small spatial scale}, volume = 5, year = 2012 }

  %0 Journal Article %1 korosi_different_2012 %A Kőrösi, Ádám %A Örvössy, Noémi %A Batáry, PéTer %A Harnos, Andrea %A Peregovits, LáSzló %D 2012 %J Insect Conservation and Diversity %N 2 %P 118--126 %R 10.1111/j.1752-4598.2011.00138.x %T Different habitat selection by two sympatric Maculinea butterflies at small spatial scale %U http://doi.wiley.com/10.1111/j.1752-4598.2011.00138.x %V 5
• Unexpected benefit of a social parasite for a key fitness component of its ant host. Hovestadt, Thomas; Thomas, Jeremy A.; Mitesser, Oliver; Elmes, Graham W.; Schoenrogge, Karsten. In American Naturalist, 179(1), pp. 110–123. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_unexpected_2012, abstract = {Numerous invertebrates inhabit social insect colonies, including the hoverfly genus Microdon, whose larvae typically live as brood predators. Formica lemani ant colonies apparently endure Microdon mutabilis infections over several years, despite losing a considerable fraction of young, and may even produce more gynes. We present a model for resource allocation within polygynous ant colonies, which assumes that whether an ant larva switches development into a worker or a gyne depends on the quantity of food received randomly from workers. Accordingly, Microdon predation promotes gyne development by increasing resource availability for surviving broods. Several model predictions are supported by empirical data. (i) Uninfected colonies seldom produce gynes. (ii) Infected colonies experience a short-lived peak in gyne production leading to a bimodal distribution in gyne production. (iii) Low brood : worker ratio is the critical mechanism controlling gyne production. (iv) Brood : worker ratio reduction must be substantial for increased gyne production to become noticeable.}, author = {Hovestadt, Thomas and Thomas, Jeremy A. and Mitesser, Oliver and Elmes, Graham W. and Schoenrogge, Karsten}, journal = {American Naturalist}, keywords = {olivervinzenzmitesser}, month = {01}, note = {WOS:000298379200012}, number = 1, pages = {110–123}, title = {Unexpected benefit of a social parasite for a key fitness component of its ant host}, volume = 179, year = 2012 }

  %0 Journal Article %1 hovestadt_unexpected_2012 %A Hovestadt, Thomas %A Thomas, Jeremy A. %A Mitesser, Oliver %A Elmes, Graham W. %A Schoenrogge, Karsten %D 2012 %J American Naturalist %N 1 %P 110--123 %R 10.1086/663203 %T Unexpected benefit of a social parasite for a key fitness component of its ant host %V 179 %X Numerous invertebrates inhabit social insect colonies, including the hoverfly genus Microdon, whose larvae typically live as brood predators. Formica lemani ant colonies apparently endure Microdon mutabilis infections over several years, despite losing a considerable fraction of young, and may even produce more gynes. We present a model for resource allocation within polygynous ant colonies, which assumes that whether an ant larva switches development into a worker or a gyne depends on the quantity of food received randomly from workers. Accordingly, Microdon predation promotes gyne development by increasing resource availability for surviving broods. Several model predictions are supported by empirical data. (i) Uninfected colonies seldom produce gynes. (ii) Infected colonies experience a short-lived peak in gyne production leading to a bimodal distribution in gyne production. (iii) Low brood : worker ratio is the critical mechanism controlling gyne production. (iv) Brood : worker ratio reduction must be substantial for increased gyne production to become noticeable.
• Evolution of dispersal in metacommunities of interacting species. Chaianunporn, T.; Hovestadt, T. In Journal of Evolutionary Biology, 25(12), pp. 2511–2525. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  @article{chaianunporn_evolution_2012, abstract = {Theoretical studies on the evolution of dispersal in metacommunities are rare despite empirical evidence suggesting that interspecific interactions can modify dispersal behaviour of organisms. To understand the role of species interactions for dispersal evolution, we utilize an individual-based model of a metacommunity where local population dynamics follows a stochastic version of the NicholsonBailey model and dispersal probability is an evolving trait. Our results show that in comparison with a neutral system (commensalism), parasitism promotes dispersal of hosts and parasites, while mutualism tends to reduce dispersal in both partners. Search efficiency of guests (only in the case of parasitism), dispersal mortality and external extinction risk can influence the evolution of dispersal of all partners. In systems composed of two host and two guest species, lower dispersal probabilities evolve under parasitism as well as mutualism than in one host and one guest species systems. This is because of frequency-dependent modulations of dispersal benefits emerging in such systems for all partners.}, author = {Chaianunporn, T. and Hovestadt, T.}, journal = {Journal of Evolutionary Biology}, keywords = {CLIMIT,}, month = 12, note = {WOS:000311296500012}, number = 12, pages = {2511–2525}, title = {Evolution of dispersal in metacommunities of interacting species}, volume = 25, year = 2012 }

  %0 Journal Article %1 chaianunporn_evolution_2012 %A Chaianunporn, T. %A Hovestadt, T. %D 2012 %J Journal of Evolutionary Biology %N 12 %P 2511--2525 %R 10.1111/j.1420-9101.2012.02620.x %T Evolution of dispersal in metacommunities of interacting species %V 25 %X Theoretical studies on the evolution of dispersal in metacommunities are rare despite empirical evidence suggesting that interspecific interactions can modify dispersal behaviour of organisms. To understand the role of species interactions for dispersal evolution, we utilize an individual-based model of a metacommunity where local population dynamics follows a stochastic version of the NicholsonBailey model and dispersal probability is an evolving trait. Our results show that in comparison with a neutral system (commensalism), parasitism promotes dispersal of hosts and parasites, while mutualism tends to reduce dispersal in both partners. Search efficiency of guests (only in the case of parasitism), dispersal mortality and external extinction risk can influence the evolution of dispersal of all partners. In systems composed of two host and two guest species, lower dispersal probabilities evolve under parasitism as well as mutualism than in one host and one guest species systems. This is because of frequency-dependent modulations of dispersal benefits emerging in such systems for all partners.
• Population dynamics of plant and pollinator communities: Stability reconsidered. Benadi, Gita; Blüthgen, Nico; Hovestadt, Thomas; Poethke, Hans-Joachim. In American Naturalist, 179(2), pp. 157–168. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  @article{benadi_population_2012, abstract = {Plant-pollinator networks are systems of outstanding ecological and economic importance. A particularly intriguing aspect of these systems is their high diversity. However, earlier studies have concluded that the specific mechanisms of plant-pollinator interactions are destabilizing and should lead to a loss of diversity. Here we present a mechanistic model of plant and pollinator population dynamics with the ability to represent a broad spectrum of interaction structures. Using this model, we examined the influence of pollinators on the stability of a plant community and the relationship between pollinator specialization and stability. In accordance with earlier work, our results show that plant-pollinator interactions may severely destabilize plant coexistence, regardless of the degree of pollinator specialization. However, if plant niche differentiation, a classical stabilizing mechanism, is sufficiently strong to overcome the minority disadvantage with respect to pollination, interactions with pollinators may even increase the stability of a plant community. In addition to plant niche differentiation, the relationship between specialization and stability depends on a number of parameters that affect pollinator growth rates. Our results highlight the complex effects of this particular type of mutualism on community stability and call for further investigations of the mechanisms of diversity maintenance in plant-pollinator systems.}, author = {Benadi, Gita and Blüthgen, Nico and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {American Naturalist}, keywords = {imported}, month = {02}, note = {WOS:000299000400005}, number = 2, pages = {157–168}, title = {Population dynamics of plant and pollinator communities: {Stability} reconsidered}, volume = 179, year = 2012 }

  %0 Journal Article %1 benadi_population_2012 %A Benadi, Gita %A Blüthgen, Nico %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2012 %J American Naturalist %N 2 %P 157--168 %R 10.1086/663685 %T Population dynamics of plant and pollinator communities: Stability reconsidered %V 179 %X Plant-pollinator networks are systems of outstanding ecological and economic importance. A particularly intriguing aspect of these systems is their high diversity. However, earlier studies have concluded that the specific mechanisms of plant-pollinator interactions are destabilizing and should lead to a loss of diversity. Here we present a mechanistic model of plant and pollinator population dynamics with the ability to represent a broad spectrum of interaction structures. Using this model, we examined the influence of pollinators on the stability of a plant community and the relationship between pollinator specialization and stability. In accordance with earlier work, our results show that plant-pollinator interactions may severely destabilize plant coexistence, regardless of the degree of pollinator specialization. However, if plant niche differentiation, a classical stabilizing mechanism, is sufficiently strong to overcome the minority disadvantage with respect to pollination, interactions with pollinators may even increase the stability of a plant community. In addition to plant niche differentiation, the relationship between specialization and stability depends on a number of parameters that affect pollinator growth rates. Our results highlight the complex effects of this particular type of mutualism on community stability and call for further investigations of the mechanisms of diversity maintenance in plant-pollinator systems.
• Concurrent evolution of random dispersal and habitat niche width in host-parasitoid systems. Chaianunporn, Thotsapol; Hovestadt, Thomas. In Ecological Modelling, 247, pp. 241–250. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  @article{chaianunporn_concurrent_2012, abstract = {Antagonistic interactions like those between hosts and parasites or parasitoids or between predators and prey are important for many ecological and evolutionary processes. Here, we contrast the effect of commensalism and host-parasitoid interaction (complete fertility loss for infected host), on the concurrent evolution of host dispersal and habitat niche width. We assume that host habitat niche width is associated with a fertility trade-off; the wider the habitat niche, the lower the maximum fertility in optimal habitats. We implement a spatially explicit, individual-based one-host-one-guest metacommunity model (guest species are commensals or parasitoids) with landscape heterogeneity of a continuous habitat trait that affects the host's fertility only. The antagonistic interaction model follows the Nicholson-Bailey equation. Compared to commensalism, the host-parasitoid interaction promotes the evolution of higher dispersal probability in hosts and guests. In comparison to homogeneous landscapes, lower dispersal probabilities of both hosts and guests evolve in heterogeneous landscapes. Other than in homogeneous landscapes, parasitoids typically evolve higher dispersal probabilities than their hosts in heterogeneous landscapes. The effect of landscape heterogeneity on dispersal evolution depends on the magnitude of the habitat-fertility trade-off for hosts and the search efficiency of parasitoids. Moreover, depending on the habitat-fertility trade-off, antagonistic interactions may promote evolution of habitat niche width in hosts. Landscape structure affects the evolution of dispersal and habitat niche width in opposite ways: in clustered (autocorrelated) landscapes, dispersal probability evolves to higher, but habitat niche width to lower levels than in random landscapes. (C) 2012 Elsevier B.V. All rights reserved.}, author = {Chaianunporn, Thotsapol and Hovestadt, Thomas}, journal = {Ecological Modelling}, keywords = {CLIMIT,}, month = 12, note = {WOS:000313089600022}, pages = {241–250}, title = {Concurrent evolution of random dispersal and habitat niche width in host-parasitoid systems}, volume = 247, year = 2012 }

  %0 Journal Article %1 chaianunporn_concurrent_2012 %A Chaianunporn, Thotsapol %A Hovestadt, Thomas %D 2012 %J Ecological Modelling %P 241--250 %R 10.1016/j.ecolmodel.2012.09.005 %T Concurrent evolution of random dispersal and habitat niche width in host-parasitoid systems %V 247 %X Antagonistic interactions like those between hosts and parasites or parasitoids or between predators and prey are important for many ecological and evolutionary processes. Here, we contrast the effect of commensalism and host-parasitoid interaction (complete fertility loss for infected host), on the concurrent evolution of host dispersal and habitat niche width. We assume that host habitat niche width is associated with a fertility trade-off; the wider the habitat niche, the lower the maximum fertility in optimal habitats. We implement a spatially explicit, individual-based one-host-one-guest metacommunity model (guest species are commensals or parasitoids) with landscape heterogeneity of a continuous habitat trait that affects the host's fertility only. The antagonistic interaction model follows the Nicholson-Bailey equation. Compared to commensalism, the host-parasitoid interaction promotes the evolution of higher dispersal probability in hosts and guests. In comparison to homogeneous landscapes, lower dispersal probabilities of both hosts and guests evolve in heterogeneous landscapes. Other than in homogeneous landscapes, parasitoids typically evolve higher dispersal probabilities than their hosts in heterogeneous landscapes. The effect of landscape heterogeneity on dispersal evolution depends on the magnitude of the habitat-fertility trade-off for hosts and the search efficiency of parasitoids. Moreover, depending on the habitat-fertility trade-off, antagonistic interactions may promote evolution of habitat niche width in hosts. Landscape structure affects the evolution of dispersal and habitat niche width in opposite ways: in clustered (autocorrelated) landscapes, dispersal probability evolves to higher, but habitat niche width to lower levels than in random landscapes. (C) 2012 Elsevier B.V. All rights reserved.
• Risky movement increases the rate of range expansion. Bartoń, Kamil A.; Hovestadt, T.; Phillips, B. L.; Travis, J. M. J. In Proceedings of the Royal Society B-Biological Sciences, 279(1731), pp. 1194–1202. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  @article{barton_risky_2012, abstract = {The movement rules used by an individual determine both its survival and dispersal success. Here, we develop a simple model that links inter-patch movement behaviour with population dynamics in order to explore how individual dispersal behaviour influences not only its dispersal and survival, but also the population's rate of range expansion. Whereas dispersers are most likely to survive when they follow nearly straight lines and rapidly orient movement towards a non-natal patch, the most rapid rates of range expansion are obtained for trajectories in which individuals delay biasing their movement towards a non-natal patch. This result is robust to the spatial structure of the landscape. Importantly, in a set of evolutionary simulations, we also demonstrate that the movement strategy that evolves at an expanding front is much closer to that maximizing the rate of range expansion than that which maximizes the survival of dispersers. Our results suggest that if one of our conservation goals is the facilitation of range-shifting, then current indices of connectivity need to be complemented by the development and utilization of new indices providing a measure of the ease with which a species spreads across a landscape.}, author = {Bartoń, Kamil A. and Hovestadt, T. and Phillips, B. L. and Travis, J. M. J.}, journal = {Proceedings of the Royal Society B-Biological Sciences}, keywords = {TenLamas}, month = {03}, note = {WOS:000300417000020}, number = 1731, pages = {1194–1202}, title = {Risky movement increases the rate of range expansion}, volume = 279, year = 2012 }

  %0 Journal Article %1 barton_risky_2012 %A Bartoń, Kamil A. %A Hovestadt, T. %A Phillips, B. L. %A Travis, J. M. J. %D 2012 %J Proceedings of the Royal Society B-Biological Sciences %N 1731 %P 1194--1202 %R 10.1098/rspb.2011.1254 %T Risky movement increases the rate of range expansion %V 279 %X The movement rules used by an individual determine both its survival and dispersal success. Here, we develop a simple model that links inter-patch movement behaviour with population dynamics in order to explore how individual dispersal behaviour influences not only its dispersal and survival, but also the population's rate of range expansion. Whereas dispersers are most likely to survive when they follow nearly straight lines and rapidly orient movement towards a non-natal patch, the most rapid rates of range expansion are obtained for trajectories in which individuals delay biasing their movement towards a non-natal patch. This result is robust to the spatial structure of the landscape. Importantly, in a set of evolutionary simulations, we also demonstrate that the movement strategy that evolves at an expanding front is much closer to that maximizing the rate of range expansion than that which maximizes the survival of dispersers. Our results suggest that if one of our conservation goals is the facilitation of range-shifting, then current indices of connectivity need to be complemented by the development and utilization of new indices providing a measure of the ease with which a species spreads across a landscape.
• Costs of dispersal. Bonte, Dries; Van Dyck, Hans; Bullock, James M.; Coulon, Aurelie; Delgado, Maria; Gibbs, Melanie; Lehouck, Valerie; Matthysen, Erik; Mustin, Karin; Saastamoinen, Marjo; Schtickzelle, Nicolas; Stevens, Virginie M.; Vandewoestijne, Sofie; Baguette, Michel; Barton, Kamil; Benton, Tim G.; Chaput-Bardy, Audrey; Clobert, Jean; Dytham, Calvin; Hovestadt, Thomas; Meier, Christoph M.; Palmer, Steve C. F.; Turlure, Camille; Travis, Justin M. J. In Biological Reviews, 87(2), pp. 290–312. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  @article{bonte_costs_2012, abstract = {Dispersal costs can be classified into energetic, time, risk and opportunity costs and may be levied directly or deferred during departure, transfer and settlement. They may equally be incurred during life stages before the actual dispersal event through investments in special morphologies. Because costs will eventually determine the performance of dispersing individuals and the evolution of dispersal, we here provide an extensive review on the different cost types that occur during dispersal in a wide array of organisms, ranging from micro-organisms to plants, invertebrates and vertebrates. In general, costs of transfer have been more widely documented in actively dispersing organisms, in contrast to a greater focus on costs during departure and settlement in plants and animals with a passive transfer phase. Costs related to the development of specific dispersal attributes appear to be much more prominent than previously accepted. Because costs induce trade-offs, they give rise to covariation between dispersal and other life-history traits at different scales of organismal organisation. The consequences of (i) the presence and magnitude of different costs during different phases of the dispersal process, and (ii) their internal organisation through covariation with other life-history traits, are synthesised with respect to potential consequences for species conservation and the need for development of a new generation of spatial simulation models.}, author = {Bonte, Dries and Van Dyck, Hans and Bullock, James M. and Coulon, Aurelie and Delgado, Maria and Gibbs, Melanie and Lehouck, Valerie and Matthysen, Erik and Mustin, Karin and Saastamoinen, Marjo and Schtickzelle, Nicolas and Stevens, Virginie M. and Vandewoestijne, Sofie and Baguette, Michel and Barton, Kamil and Benton, Tim G. and Chaput-Bardy, Audrey and Clobert, Jean and Dytham, Calvin and Hovestadt, Thomas and Meier, Christoph M. and Palmer, Steve C. F. and Turlure, Camille and Travis, Justin M. J.}, journal = {Biological Reviews}, keywords = {imported}, month = {05}, note = {WOS:000302351300003}, number = 2, pages = {290–312}, title = {Costs of dispersal}, volume = 87, year = 2012 }

  %0 Journal Article %1 bonte_costs_2012 %A Bonte, Dries %A Van Dyck, Hans %A Bullock, James M. %A Coulon, Aurelie %A Delgado, Maria %A Gibbs, Melanie %A Lehouck, Valerie %A Matthysen, Erik %A Mustin, Karin %A Saastamoinen, Marjo %A Schtickzelle, Nicolas %A Stevens, Virginie M. %A Vandewoestijne, Sofie %A Baguette, Michel %A Barton, Kamil %A Benton, Tim G. %A Chaput-Bardy, Audrey %A Clobert, Jean %A Dytham, Calvin %A Hovestadt, Thomas %A Meier, Christoph M. %A Palmer, Steve C. F. %A Turlure, Camille %A Travis, Justin M. J. %D 2012 %J Biological Reviews %N 2 %P 290--312 %R 10.1111/j.1469-185X.2011.00201.x %T Costs of dispersal %V 87 %X Dispersal costs can be classified into energetic, time, risk and opportunity costs and may be levied directly or deferred during departure, transfer and settlement. They may equally be incurred during life stages before the actual dispersal event through investments in special morphologies. Because costs will eventually determine the performance of dispersing individuals and the evolution of dispersal, we here provide an extensive review on the different cost types that occur during dispersal in a wide array of organisms, ranging from micro-organisms to plants, invertebrates and vertebrates. In general, costs of transfer have been more widely documented in actively dispersing organisms, in contrast to a greater focus on costs during departure and settlement in plants and animals with a passive transfer phase. Costs related to the development of specific dispersal attributes appear to be much more prominent than previously accepted. Because costs induce trade-offs, they give rise to covariation between dispersal and other life-history traits at different scales of organismal organisation. The consequences of (i) the presence and magnitude of different costs during different phases of the dispersal process, and (ii) their internal organisation through covariation with other life-history traits, are synthesised with respect to potential consequences for species conservation and the need for development of a new generation of spatial simulation models.
• Why are metapopulations so rare?. Fronhofer, Emanuel A.; Kubisch, Alexander; Hilker, Frank M.; Hovestadt, Thomas; Poethke, Hans Joachim. In Ecology, 93(8), pp. 1967–1978. 2012.
  • [ BibTeX ]
  • [ EndNote ]
  @article{fronhofer_why_2012, abstract = {Roughly 40 years after its introduction, the metapopulation concept is central to population ecology. The notion that local populations and their dynamics may be coupled by dispersal is without any doubt of great importance for our understanding of population-level processes. A metapopulation describes a set of subpopulations linked by (rare) dispersal events in a dynamic equilibrium of extinctions and recolonizations. In the large body of literature that has accumulated, the term "metapopulation'' is often used in a very broad sense; most of the time it simply implies spatial heterogeneity. A number of reviews have recently addressed this problem and have pointed out that, despite the large and still growing popularity of the metapopulation concept, there are only very few empirical examples that conform with the strict classical metapopulation (CM) definition. In order to understand this discrepancy between theory and observation, we use an individual-based modeling approach that allows us to pinpoint the environmental conditions and the life-history attributes required for the emergence of a CM structure. We find that CM dynamics are restricted to a specific parameter range at the border between spatially structured but completely occupied and globally extinct populations. Considering general life-history attributes, our simulations suggest that CMs are more likely to occur in arthropod species than in (large) vertebrates. Since the specific type of spatial population structure determines conservation concepts, our findings have important implications for conservation biology. Our model suggests that most spatially structured populations are panmictic, patchy, or of mainland-island type, which makes efforts spent on increasing connectivity (e.g., corridors) questionable. If one does observe a true CM structure, this means that the focal metapopulation is on the brink of extinction and that drastic conservation measures are needed.}, author = {Fronhofer, Emanuel A. and Kubisch, Alexander and Hilker, Frank M. and Hovestadt, Thomas and Poethke, Hans Joachim}, journal = {Ecology}, keywords = {metapopulation}, month = {08}, note = {WOS:000307214000021}, number = 8, pages = {1967–1978}, title = {Why are metapopulations so rare?}, volume = 93, year = 2012 }

  %0 Journal Article %1 fronhofer_why_2012 %A Fronhofer, Emanuel A. %A Kubisch, Alexander %A Hilker, Frank M. %A Hovestadt, Thomas %A Poethke, Hans Joachim %D 2012 %J Ecology %N 8 %P 1967--1978 %T Why are metapopulations so rare? %V 93 %X Roughly 40 years after its introduction, the metapopulation concept is central to population ecology. The notion that local populations and their dynamics may be coupled by dispersal is without any doubt of great importance for our understanding of population-level processes. A metapopulation describes a set of subpopulations linked by (rare) dispersal events in a dynamic equilibrium of extinctions and recolonizations. In the large body of literature that has accumulated, the term "metapopulation'' is often used in a very broad sense; most of the time it simply implies spatial heterogeneity. A number of reviews have recently addressed this problem and have pointed out that, despite the large and still growing popularity of the metapopulation concept, there are only very few empirical examples that conform with the strict classical metapopulation (CM) definition. In order to understand this discrepancy between theory and observation, we use an individual-based modeling approach that allows us to pinpoint the environmental conditions and the life-history attributes required for the emergence of a CM structure. We find that CM dynamics are restricted to a specific parameter range at the border between spatially structured but completely occupied and globally extinct populations. Considering general life-history attributes, our simulations suggest that CMs are more likely to occur in arthropod species than in (large) vertebrates. Since the specific type of spatial population structure determines conservation concepts, our findings have important implications for conservation biology. Our model suggests that most spatially structured populations are panmictic, patchy, or of mainland-island type, which makes efforts spent on increasing connectivity (e.g., corridors) questionable. If one does observe a true CM structure, this means that the focal metapopulation is on the brink of extinction and that drastic conservation measures are needed.

• Do all inter-patch movements represent dispersal? A mixed kernel study of butterfly mobility in fragmented landscapes. Hovestadt, Thomas; Binzenhoefer, Birgit; Nowicki, Piotr; Settele, Josef. In Journal of Animal Ecology, 80(5), pp. 1070–1077. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_all_2011, abstract = {1. In times of ongoing habitat fragmentation, the persistence of many species is determined by their dispersal abilities. Consequently, understanding the rules underlying movement between habitat patches is a key issue in conservation ecology. 2. We have analysed mark-release-recapture (MRR) data on inter-patches movements of the Dusky Large Blue butterfly Maculinea nausithous in a fragmented landscape in northern Bavaria, Germany. The aim of the analysis was to quantify distance dependence of dispersal as well as to evaluate the effect of target patch area on immigration probability. For statistical evaluation, we apply a 'reduced version' of the virtual migration model (VM), only fitting parameters for dispersal distance and immigration. In contrast to other analyses, we fit a mixed dispersal kernel to the MRR data. 3. A large fraction of recaptures happened in other habitat patches than those where individuals were initially caught. Further, we found significant evidence for the presence of a mixed dispersal kernel. The results indicate that individuals follow different strategies in their movements. Most movements are performed over small distances, nonetheless involving travelling between nearby habitat patches (median distance c. 480 m). A small fraction (c. 0 025) of the population has a tendency to move over larger distances (median distance c. 3800 m). Further, immigration was positively affected by patch area (I similar to A(zeta)), with the scaling parameter zeta = 0.5. 4. Our findings should help to resolve the long-lasting dispute over the suitability of the negative exponential function vs. inverse-power one for modelling dispersal. Previous studies on various organisms found that the former typically gives better overall fit to empirical distance distributions, but that the latter better represents long-distance movement probabilities. As long-distance movements are more important for landscape-level effects and thus, e. g. for conservation-oriented analyses like PVAs, fitting inverse-power kernels has often been preferred. 5. We conclude that the above discrepancy may simply stem from the fact that recorded inter-patch movements are an outcome of two different processes: daily routine movements and genuine dispersal. Consequently, applying mixed dispersal kernels to disentangle the two processes is recommended.}, author = {Hovestadt, Thomas and Binzenhoefer, Birgit and Nowicki, Piotr and Settele, Josef}, journal = {Journal of Animal Ecology}, keywords = {CLIMIT}, month = {09}, note = {WOS:000293176400018}, number = 5, pages = {1070–1077}, title = {Do all inter-patch movements represent dispersal? {A} mixed kernel study of butterfly mobility in fragmented landscapes}, volume = 80, year = 2011 }

  %0 Journal Article %1 hovestadt_all_2011 %A Hovestadt, Thomas %A Binzenhoefer, Birgit %A Nowicki, Piotr %A Settele, Josef %D 2011 %J Journal of Animal Ecology %N 5 %P 1070--1077 %R 10.1111/j.1365-2656.2011.01848.x %T Do all inter-patch movements represent dispersal? A mixed kernel study of butterfly mobility in fragmented landscapes %V 80 %X 1. In times of ongoing habitat fragmentation, the persistence of many species is determined by their dispersal abilities. Consequently, understanding the rules underlying movement between habitat patches is a key issue in conservation ecology. 2. We have analysed mark-release-recapture (MRR) data on inter-patches movements of the Dusky Large Blue butterfly Maculinea nausithous in a fragmented landscape in northern Bavaria, Germany. The aim of the analysis was to quantify distance dependence of dispersal as well as to evaluate the effect of target patch area on immigration probability. For statistical evaluation, we apply a 'reduced version' of the virtual migration model (VM), only fitting parameters for dispersal distance and immigration. In contrast to other analyses, we fit a mixed dispersal kernel to the MRR data. 3. A large fraction of recaptures happened in other habitat patches than those where individuals were initially caught. Further, we found significant evidence for the presence of a mixed dispersal kernel. The results indicate that individuals follow different strategies in their movements. Most movements are performed over small distances, nonetheless involving travelling between nearby habitat patches (median distance c. 480 m). A small fraction (c. 0 025) of the population has a tendency to move over larger distances (median distance c. 3800 m). Further, immigration was positively affected by patch area (I similar to A(zeta)), with the scaling parameter zeta = 0.5. 4. Our findings should help to resolve the long-lasting dispute over the suitability of the negative exponential function vs. inverse-power one for modelling dispersal. Previous studies on various organisms found that the former typically gives better overall fit to empirical distance distributions, but that the latter better represents long-distance movement probabilities. As long-distance movements are more important for landscape-level effects and thus, e. g. for conservation-oriented analyses like PVAs, fitting inverse-power kernels has often been preferred. 5. We conclude that the above discrepancy may simply stem from the fact that recorded inter-patch movements are an outcome of two different processes: daily routine movements and genuine dispersal. Consequently, applying mixed dispersal kernels to disentangle the two processes is recommended.
• An updated algorithm for the generation of neutral landscapes by spectral synthesis. Chipperfield, Joseph D.; Dytham, Calvin; Hovestadt, Thomas. In Plos One, 6(2), p. e17040. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  @article{chipperfield_updated_2011, abstract = {Background: Patterns that arise from an ecological process can be driven as much from the landscape over which the process is run as it is by some intrinsic properties of the process itself. The disentanglement of these effects is aided if it possible to run models of the process over artificial landscapes with controllable spatial properties. A number of different methods for the generation of so-called 'neutral landscapes' have been developed to provide just such a tool. Of these methods, a particular class that simulate fractional Brownian motion have shown particular promise. The existing methods of simulating fractional Brownian motion suffer from a number of problems however: they are often not easily generalisable to an arbitrary number of dimensions and produce outputs that can exhibit some undesirable artefacts. Methodology: We describe here an updated algorithm for the generation of neutral landscapes by fractional Brownian motion that do not display such undesirable properties. Using Monte Carlo simulation we assess the anisotropic properties of landscapes generated using the new algorithm described in this paper and compare it against a popular benchmark algorithm. Conclusion/Significance: The results show that the existing algorithm creates landscapes with values strongly correlated in the diagonal direction and that the new algorithm presented here corrects this artefact. A number of extensions of the algorithm described here are also highlighted: we describe how the algorithm can be employed to generate landscapes that display different properties in different dimensions and how they can be combined with an environmental gradient to produce landscapes that combine environmental variation at the local and macro scales.}, author = {Chipperfield, Joseph D. and Dytham, Calvin and Hovestadt, Thomas}, journal = {Plos One}, keywords = {methods}, month = {02}, note = {WOS:000287369200015}, number = 2, pages = {e17040}, title = {An updated algorithm for the generation of neutral landscapes by spectral synthesis}, volume = 6, year = 2011 }

  %0 Journal Article %1 chipperfield_updated_2011 %A Chipperfield, Joseph D. %A Dytham, Calvin %A Hovestadt, Thomas %D 2011 %J Plos One %N 2 %P e17040 %R 10.1371/journal.pone.0017040 %T An updated algorithm for the generation of neutral landscapes by spectral synthesis %V 6 %X Background: Patterns that arise from an ecological process can be driven as much from the landscape over which the process is run as it is by some intrinsic properties of the process itself. The disentanglement of these effects is aided if it possible to run models of the process over artificial landscapes with controllable spatial properties. A number of different methods for the generation of so-called 'neutral landscapes' have been developed to provide just such a tool. Of these methods, a particular class that simulate fractional Brownian motion have shown particular promise. The existing methods of simulating fractional Brownian motion suffer from a number of problems however: they are often not easily generalisable to an arbitrary number of dimensions and produce outputs that can exhibit some undesirable artefacts. Methodology: We describe here an updated algorithm for the generation of neutral landscapes by fractional Brownian motion that do not display such undesirable properties. Using Monte Carlo simulation we assess the anisotropic properties of landscapes generated using the new algorithm described in this paper and compare it against a popular benchmark algorithm. Conclusion/Significance: The results show that the existing algorithm creates landscapes with values strongly correlated in the diagonal direction and that the new algorithm presented here corrects this artefact. A number of extensions of the algorithm described here are also highlighted: we describe how the algorithm can be employed to generate landscapes that display different properties in different dimensions and how they can be combined with an environmental gradient to produce landscapes that combine environmental variation at the local and macro scales.
• On the approximation of continuous dispersal kernels in discrete-space models: Approximating continuous dispersal on lattices. Chipperfield, Joseph D.; Holland, E. Penelope; Dytham, Calvin; Thomas, Chris D.; Hovestadt, Thomas. In Methods in Ecology and Evolution, 2(6), pp. 668–681. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{chipperfield_approximation_2011, author = {Chipperfield, Joseph D. and Holland, E. Penelope and Dytham, Calvin and Thomas, Chris D. and Hovestadt, Thomas}, journal = {Methods in Ecology and Evolution}, keywords = {dispersal}, month = 12, number = 6, pages = {668–681}, title = {On the approximation of continuous dispersal kernels in discrete-space models: {Approximating} continuous dispersal on lattices}, volume = 2, year = 2011 }

  %0 Journal Article %1 chipperfield_approximation_2011 %A Chipperfield, Joseph D. %A Holland, E. Penelope %A Dytham, Calvin %A Thomas, Chris D. %A Hovestadt, Thomas %D 2011 %J Methods in Ecology and Evolution %N 6 %P 668--681 %R 10.1111/j.2041-210X.2011.00117.x %T On the approximation of continuous dispersal kernels in discrete-space models: Approximating continuous dispersal on lattices %U http://doi.wiley.com/10.1111/j.2041-210X.2011.00117.x %V 2
• The role of mobility for the emergence of diversity in victim-exploiter systems. Chaianunporn, T.; Hovestadt, T. In Journal of Evolutionary Biology, 24(11), pp. 2473–2484. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  @article{chaianunporn_role_2011, abstract = {Theoretical and empirical studies indicate that exploitation is a possible driver of exploiter and victim diversification. However, there are many factors which could promote and limit this diversification process. Using a spatially explicit individual-based model, where an exploiters success depends on matching between its own and a victims continuous trait, we simulate local communities of victims and exploiters. We investigate how exploiter mobility (searching ability and movement strategies) can influence diversification of victims. We find that if victim traits are under intermediate intensity of stabilizing selection, disruptive selection exerted by exploiters can indeed lead to diversification in victim population and the victim trait distribution can split into two or more groups. Searching ability and movement strategy of exploiters (local vs. global movement) play a role in determining the number of victim trait groups emerging. Moreover, they affect the proportion of infected victims and the formation of spatial patterns in the victim trait distribution. In addition, with a high searching ability, exploiters with global movement drive victims to be more diverse than exploiters with local movement.}, author = {Chaianunporn, T. and Hovestadt, T.}, journal = {Journal of Evolutionary Biology}, keywords = {diversity}, month = 11, note = {WOS:000297325600016}, number = 11, pages = {2473–2484}, title = {The role of mobility for the emergence of diversity in victim-exploiter systems}, volume = 24, year = 2011 }

  %0 Journal Article %1 chaianunporn_role_2011 %A Chaianunporn, T. %A Hovestadt, T. %D 2011 %J Journal of Evolutionary Biology %N 11 %P 2473--2484 %R 10.1111/j.1420-9101.2011.02375.x %T The role of mobility for the emergence of diversity in victim-exploiter systems %V 24 %X Theoretical and empirical studies indicate that exploitation is a possible driver of exploiter and victim diversification. However, there are many factors which could promote and limit this diversification process. Using a spatially explicit individual-based model, where an exploiters success depends on matching between its own and a victims continuous trait, we simulate local communities of victims and exploiters. We investigate how exploiter mobility (searching ability and movement strategies) can influence diversification of victims. We find that if victim traits are under intermediate intensity of stabilizing selection, disruptive selection exerted by exploiters can indeed lead to diversification in victim population and the victim trait distribution can split into two or more groups. Searching ability and movement strategy of exploiters (local vs. global movement) play a role in determining the number of victim trait groups emerging. Moreover, they affect the proportion of infected victims and the formation of spatial patterns in the victim trait distribution. In addition, with a high searching ability, exploiters with global movement drive victims to be more diverse than exploiters with local movement.
• Density-dependent dispersal and the formation of range borders. Kubisch, Alexander; Poethke, Hans-Joachim; Hovestadt, Thomas. In Ecography, 34(6), pp. 1002–1008. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  @article{kubisch_density-dependent_2011, abstract = {Knowledge about the mechanisms of range formation is crucial for scientifically based species conservation strategies in the face of ongoing global climate change. In recent years an increasing amount of studies have focused on the influences of density-dependent dispersal on demographic and biogeographical patterns. However, it still remains unclear, to what extent and in what ways this strategy would affect the range formation of species. In order to fill this gap, we present a study using individual-based simulations of a species with discrete generations living along a dispersal mortality gradient. We compare the evolution of range sizes for species following density-dependent and density-independent emigration. Furthermore we assess the influence of environmental stochasticity and Allee effects on range formation, as both processes are known to play an important role for dispersal evolution. We find that density-dependent dispersal always results in much wider ranges than unconditional dispersal. Increasing environmental stochasticity, a predicted consequence of climate change, can remarkably expand the ranges of species living in such connectivity gradients if dispersal decisions are based on local population density. A strong Allee effect causes range contraction for both strategies, but the effect is considerably less dramatic under density-dependent compared to density-independent emigration. We strongly recommend accounting for these findings in future attempts to model species range shifts due to climate change.}, author = {Kubisch, Alexander and Poethke, Hans-Joachim and Hovestadt, Thomas}, journal = {Ecography}, keywords = {dispersal}, month = 12, note = {WOS:000297738200010}, number = 6, pages = {1002–1008}, title = {Density-dependent dispersal and the formation of range borders.}, volume = 34, year = 2011 }

  %0 Journal Article %1 kubisch_density-dependent_2011 %A Kubisch, Alexander %A Poethke, Hans-Joachim %A Hovestadt, Thomas %D 2011 %J Ecography %N 6 %P 1002--1008 %R 10.1111/j.1600-0587.2010.06744.x %T Density-dependent dispersal and the formation of range borders. %V 34 %X Knowledge about the mechanisms of range formation is crucial for scientifically based species conservation strategies in the face of ongoing global climate change. In recent years an increasing amount of studies have focused on the influences of density-dependent dispersal on demographic and biogeographical patterns. However, it still remains unclear, to what extent and in what ways this strategy would affect the range formation of species. In order to fill this gap, we present a study using individual-based simulations of a species with discrete generations living along a dispersal mortality gradient. We compare the evolution of range sizes for species following density-dependent and density-independent emigration. Furthermore we assess the influence of environmental stochasticity and Allee effects on range formation, as both processes are known to play an important role for dispersal evolution. We find that density-dependent dispersal always results in much wider ranges than unconditional dispersal. Increasing environmental stochasticity, a predicted consequence of climate change, can remarkably expand the ranges of species living in such connectivity gradients if dispersal decisions are based on local population density. A strong Allee effect causes range contraction for both strategies, but the effect is considerably less dramatic under density-dependent compared to density-independent emigration. We strongly recommend accounting for these findings in future attempts to model species range shifts due to climate change.
• Range border formation in a world with increasing climatic variance. Kubisch, Alexander; Poethke, Hans-Joachim. In Evolutionary Ecology Research, 13(2), pp. 159–169. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{kubisch_range_2011, author = {Kubisch, Alexander and Poethke, Hans-Joachim}, journal = {Evolutionary Ecology Research}, keywords = {imported}, number = 2, pages = {159–169}, title = {Range border formation in a world with increasing climatic variance}, volume = 13, year = 2011 }

  %0 Journal Article %1 kubisch_range_2011 %A Kubisch, Alexander %A Poethke, Hans-Joachim %D 2011 %J Evolutionary Ecology Research %N 2 %P 159--169 %T Range border formation in a world with increasing climatic variance %U http://www.evolutionary-ecology.com/abstracts/v13/2624.html %V 13
• Set-aside promotes insect and plant diversity in a Central European country. Kovács-Hostyánszki, Anikó; Kőrösi, Ádám; Orci, Kirill Márk; Batáry, Péter; Báldi, András. In Agriculture, Ecosystems & Environment, 141(3–4), pp. 296–301. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{kovacs-hostyanszki_set-aside_2011, abstract = {The area of non-cropped habitats has been decreasing in Europe largely due to land conversion into cropland and energy crops. In Hungary, special agri-environment schemes in Environmentally Sensitive Areas require the establishment of sown set-aside fields especially for endangered bird species. We tested if these set-aside fields are beneficial for plants and insects of agricultural landscapes. We compared the herbaceous flora, grasshopper (Orthoptera), bee (Apidae) and butterfly (Rhopalocera) fauna of five field types (1, 2 and 3 year-old set-aside, winter cereal fields and semi-natural grasslands). Species richness, abundance and species composition of insects were tested against field type and plant species richness. The wheat fields were the poorest habitats for all taxa. The species richness and abundance of the studied insects were usually higher in set-aside than in cereal fields with no significant difference between set-aside of different age. We found the highest number of orthopteran species and butterfly individuals in semi-natural grasslands. At community level, field type and plant species richness had a significant effect on orthopteran assemblages. Butterfly assemblages were significantly affected by field type. Bee assemblages were not significantly related to the above variables. We can conclude that set-aside fields provide important habitat patches for plants and insects, in some cases with similar value to semi-natural grasslands. Our results emphasise the importance of set-aside within the Hungarian agri-environment scheme. Establishment of set-aside management in other Central European countries will likely to be of a similar value as the Hungarian set-aside fields.}, author = {Kovács-Hostyánszki, Anikó and Kőrösi, Ádám and Orci, Kirill Márk and Batáry, Péter and Báldi, András}, journal = {Agriculture, Ecosystems \& Environment}, keywords = {Agri-environment}, month = {05}, number = {3–4}, pages = {296–301}, title = {Set-aside promotes insect and plant diversity in a {Central} {European} country}, volume = 141, year = 2011 }

  %0 Journal Article %1 kovacs-hostyanszki_set-aside_2011 %A Kovács-Hostyánszki, Anikó %A Kőrösi, Ádám %A Orci, Kirill Márk %A Batáry, Péter %A Báldi, András %D 2011 %J Agriculture, Ecosystems & Environment %N 3–4 %P 296--301 %R 10.1016/j.agee.2011.03.004 %T Set-aside promotes insect and plant diversity in a Central European country %U http://www.sciencedirect.com/science/article/pii/S0167880911000880 %V 141 %X The area of non-cropped habitats has been decreasing in Europe largely due to land conversion into cropland and energy crops. In Hungary, special agri-environment schemes in Environmentally Sensitive Areas require the establishment of sown set-aside fields especially for endangered bird species. We tested if these set-aside fields are beneficial for plants and insects of agricultural landscapes. We compared the herbaceous flora, grasshopper (Orthoptera), bee (Apidae) and butterfly (Rhopalocera) fauna of five field types (1, 2 and 3 year-old set-aside, winter cereal fields and semi-natural grasslands). Species richness, abundance and species composition of insects were tested against field type and plant species richness. The wheat fields were the poorest habitats for all taxa. The species richness and abundance of the studied insects were usually higher in set-aside than in cereal fields with no significant difference between set-aside of different age. We found the highest number of orthopteran species and butterfly individuals in semi-natural grasslands. At community level, field type and plant species richness had a significant effect on orthopteran assemblages. Butterfly assemblages were significantly affected by field type. Bee assemblages were not significantly related to the above variables. We can conclude that set-aside fields provide important habitat patches for plants and insects, in some cases with similar value to semi-natural grasslands. Our results emphasise the importance of set-aside within the Hungarian agri-environment scheme. Establishment of set-aside management in other Central European countries will likely to be of a similar value as the Hungarian set-aside fields.
• Assortative mating counteracts the evolution of dispersal polymorphisms. Fronhofer, Emanuel A.; Kubisch, Alexander; Hovestadt, Thomas; Poethke, Hans-Joachim. In Evolution, 65(9), pp. 2461–2469. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{fronhofer_assortative_2011, author = {Fronhofer, Emanuel A. and Kubisch, Alexander and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {Evolution}, keywords = {dispersal}, month = {09}, number = 9, pages = {2461–2469}, title = {Assortative mating counteracts the evolution of dispersal polymorphisms}, volume = 65, year = 2011 }

  %0 Journal Article %1 fronhofer_assortative_2011 %A Fronhofer, Emanuel A. %A Kubisch, Alexander %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2011 %J Evolution %N 9 %P 2461--2469 %R 10.1111/j.1558-5646.2011.01312.x %T Assortative mating counteracts the evolution of dispersal polymorphisms %U http://doi.wiley.com/10.1111/j.1558-5646.2011.01312.x %V 65
• Scarce resources, risk sensitivity, and egalitarian resource sharing. Fronhofer, Emanuel A.; Pasurka, Henrik; Mitesser, Oliver; Poethke, Hans Joachim. In Evolutionary Ecology Research, 13(3), pp. 253–267. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{fronhofer_scarce_2011, author = {Fronhofer, Emanuel A. and Pasurka, Henrik and Mitesser, Oliver and Poethke, Hans Joachim}, journal = {Evolutionary Ecology Research}, keywords = {olivervinzenzmitesser}, number = 3, pages = {253–267}, title = {Scarce resources, risk sensitivity, and egalitarian resource sharing}, volume = 13, year = 2011 }

  %0 Journal Article %1 fronhofer_scarce_2011 %A Fronhofer, Emanuel A. %A Pasurka, Henrik %A Mitesser, Oliver %A Poethke, Hans Joachim %D 2011 %J Evolutionary Ecology Research %N 3 %P 253--267 %T Scarce resources, risk sensitivity, and egalitarian resource sharing %U http://www.evolutionary-ecology.com/abstracts/v13/2661.html %V 13
• Risk sensitivity revisited: from individuals to populations. Fronhofer, Emanuel A.; Pasurka, Henrik; Poitrineau, Karine; Mitesser, Oliver; Poethke, Hans-Joachim. In Animal Behaviour, 82(4), pp. 875–883. 2011.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{fronhofer_risk_2011, abstract = {Risk-sensitive foraging theory is central to behavioural ecology. It relates individual fitness to variance in foraging success (risk) and predicts which foraging strategy maximizes fitness under applicable constraints. Fitness usually comprises survival and reproduction. Yet, most models of risk-sensitive foraging have focused on only one of these two factors. Consequently, such models cannot account for the interaction between resource availability and population size, i.e. density dependence. Here, we incorporate both mortality and reproduction as functions of an individual’s risk-sensitive foraging strategy. In our model the individual strategy thus determines the mean availability of resources per capita and consequently the equilibrium population size. From a continuum of possible strategies we are able to pinpoint the exact risk-sensitive strategies that are favoured by natural selection in saturated habitats and demonstrate that, in addition to risk proneness and risk aversion, a number of optimal intermediate variances can be selected for. In contrast to predictions based on models that ignore the interaction between behaviour, population density and resource availability, our results show that high baseline mortality (e.g. predation risk) does not necessarily lead to risk proneness. In addition to this novel finding, our model confirms the crucial importance of resource-independent (baseline) mortality for optimal risk-sensitive behaviour.}, author = {Fronhofer, Emanuel A. and Pasurka, Henrik and Poitrineau, Karine and Mitesser, Oliver and Poethke, Hans-Joachim}, journal = {Animal Behaviour}, keywords = {mortality,}, month = 10, number = 4, pages = {875–883}, title = {Risk sensitivity revisited: from individuals to populations}, volume = 82, year = 2011 }

  %0 Journal Article %1 fronhofer_risk_2011 %A Fronhofer, Emanuel A. %A Pasurka, Henrik %A Poitrineau, Karine %A Mitesser, Oliver %A Poethke, Hans-Joachim %D 2011 %J Animal Behaviour %N 4 %P 875--883 %R 10.1016/j.anbehav.2011.07.027 %T Risk sensitivity revisited: from individuals to populations %U http://www.sciencedirect.com/science/article/pii/S0003347211003071 %V 82 %X Risk-sensitive foraging theory is central to behavioural ecology. It relates individual fitness to variance in foraging success (risk) and predicts which foraging strategy maximizes fitness under applicable constraints. Fitness usually comprises survival and reproduction. Yet, most models of risk-sensitive foraging have focused on only one of these two factors. Consequently, such models cannot account for the interaction between resource availability and population size, i.e. density dependence. Here, we incorporate both mortality and reproduction as functions of an individual’s risk-sensitive foraging strategy. In our model the individual strategy thus determines the mean availability of resources per capita and consequently the equilibrium population size. From a continuum of possible strategies we are able to pinpoint the exact risk-sensitive strategies that are favoured by natural selection in saturated habitats and demonstrate that, in addition to risk proneness and risk aversion, a number of optimal intermediate variances can be selected for. In contrast to predictions based on models that ignore the interaction between behaviour, population density and resource availability, our results show that high baseline mortality (e.g. predation risk) does not necessarily lead to risk proneness. In addition to this novel finding, our model confirms the crucial importance of resource-independent (baseline) mortality for optimal risk-sensitive behaviour.

• On the elasticity of range limits during periods of expansion. Kubisch, Alexander; Hovestadt, Thomas; Poethke, Hans-Joachim. In Ecology, 91(10), pp. 3094–3099. 2010.
  • [ BibTeX ]
  • [ EndNote ]
  @article{kubisch_elasticity_2010, abstract = {Dispersal is known to play a crucial role in the formation of species' ranges. Recent studies demonstrate that dispersiveness increases rapidly during the range expansion of species due to a fitness increase for dispersers at the expanding front. R. D. Holt concluded, however, that emigration should decline after the period of invasion and hence predicted some range contraction following the initial expansion phase. In this study, we evaluate this hypothesis using a spatially explicit individual-based model of populations distributed along environmental gradients. In our experiments we allow the species to spread along a gradient of declining conditions. Results show that range contraction did emerge in a gradient of dispersal mortality, caused by the rapid increase in emigration probability during invasion and selection disfavoring dispersal, once a stable range is formed. However, gradients in growth rate, local extinction rate, and patch capacity did not lead to a noticeable contraction of the range. We conclude, that the phenomenon of range contraction may emerge, but only under conditions that select for a reduction in dispersal at the range edge in comparison to the core region once the expansion period is over.}, author = {Kubisch, Alexander and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {Ecology}, keywords = {dispersal}, month = 10, note = {WOS:000282654700027}, number = 10, pages = {3094–3099}, title = {On the elasticity of range limits during periods of expansion}, volume = 91, year = 2010 }

  %0 Journal Article %1 kubisch_elasticity_2010 %A Kubisch, Alexander %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2010 %J Ecology %N 10 %P 3094--3099 %R 10.1890/09-2022.1 %T On the elasticity of range limits during periods of expansion %V 91 %X Dispersal is known to play a crucial role in the formation of species' ranges. Recent studies demonstrate that dispersiveness increases rapidly during the range expansion of species due to a fitness increase for dispersers at the expanding front. R. D. Holt concluded, however, that emigration should decline after the period of invasion and hence predicted some range contraction following the initial expansion phase. In this study, we evaluate this hypothesis using a spatially explicit individual-based model of populations distributed along environmental gradients. In our experiments we allow the species to spread along a gradient of declining conditions. Results show that range contraction did emerge in a gradient of dispersal mortality, caused by the rapid increase in emigration probability during invasion and selection disfavoring dispersal, once a stable range is formed. However, gradients in growth rate, local extinction rate, and patch capacity did not lead to a noticeable contraction of the range. We conclude, that the phenomenon of range contraction may emerge, but only under conditions that select for a reduction in dispersal at the range edge in comparison to the core region once the expansion period is over.
• Evolution of dispersal polymorphism and local adaptation of dispersal distance in spatially structured landscapes. Bonte, Dries; Hovestadt, Thomas; Poethke, Hans-Joachim. In Oikos, 119(3), pp. 560–566. 2010.
  • [ BibTeX ]
  • [ EndNote ]
  @article{bonte_evolution_2010, abstract = {Many organisms show polymorphism in dispersal distance strategies. This variation is particularly ecological relevant if it encompasses a functional separation of short- (SDD) and long-distance dispersal (LDD). It remains, however, an open question whether both parts of the dispersal kernel are similarly affected by landscape related selection pressures. We implemented an individual-based model to analyze the evolution of dispersal traits in firactal landscapes that vary in the proportion of habitat and its spatial configuration. Individuals are parthenogenetic with dispersal distance determined by two alleles oil each individual's genome: one allele coding for the probability of global dispersal and one allele coding for the variance sigma of a Gaussian local dispersal with mean value zero. Simulations show that mean distances of local dispersal and the probability of global dispersal, increase with increasing habitat availability, but that changes in the habitats spatial autocorrelation impose opposing selective pressure: local dispersal distances decrease and global dispersal probabilities increase with decreasing spatial autocorrelation of the available habitat. Local adaptation of local dispersal distance emerges in landscapes with less than 70\% of clumped habitat. These results demonstrate that long and short distance dispersal evolve separately according to different properties of the landscape. The landscape structure may consequently largely affect the evolution of dispersal distance strategies and the level of dispersal polymorphism.}, author = {Bonte, Dries and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {Oikos}, keywords = {imported}, month = {03}, note = {WOS:000275826200018}, number = 3, pages = {560–566}, title = {Evolution of dispersal polymorphism and local adaptation of dispersal distance in spatially structured landscapes}, volume = 119, year = 2010 }

  %0 Journal Article %1 bonte_evolution_2010 %A Bonte, Dries %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2010 %J Oikos %N 3 %P 560--566 %R 10.1111/j.1600-0706.2009.17943.x %T Evolution of dispersal polymorphism and local adaptation of dispersal distance in spatially structured landscapes %V 119 %X Many organisms show polymorphism in dispersal distance strategies. This variation is particularly ecological relevant if it encompasses a functional separation of short- (SDD) and long-distance dispersal (LDD). It remains, however, an open question whether both parts of the dispersal kernel are similarly affected by landscape related selection pressures. We implemented an individual-based model to analyze the evolution of dispersal traits in firactal landscapes that vary in the proportion of habitat and its spatial configuration. Individuals are parthenogenetic with dispersal distance determined by two alleles oil each individual's genome: one allele coding for the probability of global dispersal and one allele coding for the variance sigma of a Gaussian local dispersal with mean value zero. Simulations show that mean distances of local dispersal and the probability of global dispersal, increase with increasing habitat availability, but that changes in the habitats spatial autocorrelation impose opposing selective pressure: local dispersal distances decrease and global dispersal probabilities increase with decreasing spatial autocorrelation of the available habitat. Local adaptation of local dispersal distance emerges in landscapes with less than 70% of clumped habitat. These results demonstrate that long and short distance dispersal evolve separately according to different properties of the landscape. The landscape structure may consequently largely affect the evolution of dispersal distance strategies and the level of dispersal polymorphism.
• Information processing in models for density-dependent emigration: A comparison. Hovestadt, Thomas; Kubisch, Alexander; Poethke, Hans-Joachim. In Ecological Modelling, 221(3), pp. 405–410. 2010.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_information_2010, abstract = {Density-dependent emigration has been recognized as a fitness enhancing strategy. Yet, especially in the modelling literature there is no consensus about how density-dependent emigration should quantitatively be incorporated into metapopulation models. In this paper we compare the performance of five different dispersal strategies (defined by the functional link between density and emigration probability). Four of these strategies are based on published functional relationships between local population density and emigration probability, one assumes density-independent dispersal. We use individual-based simulations of time-discrete metapopulation dynamics and conduct evolution experiments for a broad range of values for dispersal mortality and environmental stochasticity. For each set of these conditions we analyze the evolution of emigration rates in 'monoculture experiments' (with only one type of dispersal strategy used by all individuals in the metapopulation) as well as in selection experiments that allow a pair-wise comparison of the performance of each functional type. We find that a single-parameter 'asymptotic threshold' strategy - derived from the marginal value theorem - with a decelerating increase of emigration rate with increasing population density, out-competes any other strategy, i.e. density-independent emigration, a 'linear threshold' strategy and a flexible three-parameter strategy. Only when environmental conditions select for extremely high emigration probabilities (close to one), strategies may perform approximately equally. A simple threshold strategy derived for the case of continuous population growth performs even worse than the density-independent strategy. As the functional type of the dispersal function implemented in metapopulation models may severely affect predictions concerning the survival of populations, range expansion, or community changes we clearly recommend to carefully select adequate functions to model density-dependent dispersal. (C) 2009 Elsevier B.V. All rights reserved.}, author = {Hovestadt, Thomas and Kubisch, Alexander and Poethke, Hans-Joachim}, journal = {Ecological Modelling}, keywords = {pollination}, month = {02}, note = {WOS:000273866700004}, number = 3, pages = {405–410}, title = {Information processing in models for density-dependent emigration: {A} comparison}, volume = 221, year = 2010 }

  %0 Journal Article %1 hovestadt_information_2010 %A Hovestadt, Thomas %A Kubisch, Alexander %A Poethke, Hans-Joachim %D 2010 %J Ecological Modelling %N 3 %P 405--410 %R 10.1016/j.ecolmodel.2009.11.005 %T Information processing in models for density-dependent emigration: A comparison %V 221 %X Density-dependent emigration has been recognized as a fitness enhancing strategy. Yet, especially in the modelling literature there is no consensus about how density-dependent emigration should quantitatively be incorporated into metapopulation models. In this paper we compare the performance of five different dispersal strategies (defined by the functional link between density and emigration probability). Four of these strategies are based on published functional relationships between local population density and emigration probability, one assumes density-independent dispersal. We use individual-based simulations of time-discrete metapopulation dynamics and conduct evolution experiments for a broad range of values for dispersal mortality and environmental stochasticity. For each set of these conditions we analyze the evolution of emigration rates in 'monoculture experiments' (with only one type of dispersal strategy used by all individuals in the metapopulation) as well as in selection experiments that allow a pair-wise comparison of the performance of each functional type. We find that a single-parameter 'asymptotic threshold' strategy - derived from the marginal value theorem - with a decelerating increase of emigration rate with increasing population density, out-competes any other strategy, i.e. density-independent emigration, a 'linear threshold' strategy and a flexible three-parameter strategy. Only when environmental conditions select for extremely high emigration probabilities (close to one), strategies may perform approximately equally. A simple threshold strategy derived for the case of continuous population growth performs even worse than the density-independent strategy. As the functional type of the dispersal function implemented in metapopulation models may severely affect predictions concerning the survival of populations, range expansion, or community changes we clearly recommend to carefully select adequate functions to model density-dependent dispersal. (C) 2009 Elsevier B.V. All rights reserved.

• What stops the ‘diploid male vortex’?—A simulation study for species with single locus complementary sex determination. Hein, Silke; Poethke, Hans-Joachim; Dorn, Silvia. In Ecological Modelling, 220(13–14), pp. 1663–1669. 2009.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{hein_what_2009, abstract = {The survival of hymenopteran populations especially that of ecologically and economically important pollinators and parasitoids, has become a major topic for empirical and theoretical studies. Complementary sex determination (CSD) in Hymenoptera may impose a substantial genetic load through the production of inviable or sterile diploid males. Modelling and laboratory studies have indicated that this genetic load may trigger a ‘diploid male vortex’ leading to rapid extinction of populations. Here we take a broader theoretical approach to analyze why populations exhibiting CSD persist in nature, even if they contain large proportions of homozygous diploid individuals. Using an individual-based model of spatially structured hymenopteran populations, we show that (i) inviability or reduced fertility of homozygous individuals, (ii) female-biased sex ratio, and (iii) strong intra-specific competition can mitigate the negative influence of CSD on population persistence and that (iv) already extremely low dispersal rates will result in long term survival. These findings underline the importance of life history traits for population survival and demonstrate that rather specific conditions must be met to initiate the ‘diploid male vortex’.}, author = {Hein, Silke and Poethke, Hans-Joachim and Dorn, Silvia}, journal = {Ecological Modelling}, keywords = {male}, month = {07}, number = {13–14}, pages = {1663–1669}, title = {What stops the ‘diploid male vortex’?—{A} simulation study for species with single locus complementary sex determination}, volume = 220, year = 2009 }

  %0 Journal Article %1 hein_what_2009 %A Hein, Silke %A Poethke, Hans-Joachim %A Dorn, Silvia %D 2009 %J Ecological Modelling %N 13–14 %P 1663--1669 %R 10.1016/j.ecolmodel.2009.04.001 %T What stops the ‘diploid male vortex’?—A simulation study for species with single locus complementary sex determination %U http://www.sciencedirect.com/science/article/pii/S0304380009002312 %V 220 %X The survival of hymenopteran populations especially that of ecologically and economically important pollinators and parasitoids, has become a major topic for empirical and theoretical studies. Complementary sex determination (CSD) in Hymenoptera may impose a substantial genetic load through the production of inviable or sterile diploid males. Modelling and laboratory studies have indicated that this genetic load may trigger a ‘diploid male vortex’ leading to rapid extinction of populations. Here we take a broader theoretical approach to analyze why populations exhibiting CSD persist in nature, even if they contain large proportions of homozygous diploid individuals. Using an individual-based model of spatially structured hymenopteran populations, we show that (i) inviability or reduced fertility of homozygous individuals, (ii) female-biased sex ratio, and (iii) strong intra-specific competition can mitigate the negative influence of CSD on population persistence and that (iv) already extremely low dispersal rates will result in long term survival. These findings underline the importance of life history traits for population survival and demonstrate that rather specific conditions must be met to initiate the ‘diploid male vortex’.
• Sex-specific dispersal and evolutionary rescue in metapopulations infected by male killing endosymbionts. Bonte, Dries; Hovestadt, Thomas; Poethke, Hans-Joachim. In BMC Evolutionary Biology, 9, p. 16. 2009.
  • [ BibTeX ]
  • [ EndNote ]
  @article{bonte_sex-specific_2009, abstract = {Background: Male killing endosymbionts manipulate their arthropod host reproduction by only allowing female embryos to develop into infected females and killing all male offspring. Because the resulting change in sex ratio is expected to affect the evolution of sex-specific dispersal, we investigated under which environmental conditions strong sex-biased dispersal would emerge, and how this would affect host and endosymbiont metapopulation persistence. Results: We simulated host-endosymbiont metapopulation dynamics in an individual-based model, in which dispersal rates are allowed to evolve independently for the two sexes. Prominent male-biased dispersal emerges under conditions of low environmental stochasticity and high dispersal mortality. By applying a reshuffling algorithm, we show that kin-competition is a major driver of this evolutionary pattern because of the high within-population relatedness of males compared to those of females. Moreover, the evolution of sex-specific dispersal rescues metapopulations from extinction by (i) reducing endosymbiont fixation rates and (ii) by enhancing the extinction of endosymbionts within metapopulations that are characterized by low environmental stochasticity. Conclusion: Male killing endosymbionts induce the evolution of sex-specific dispersal, with prominent male-biased dispersal under conditions of low environmental stochasticity and high dispersal mortality. This male-biased dispersal emerges from stronger kin-competition in males compared to females and induces an evolutionary rescue mechanism.}, author = {Bonte, Dries and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {BMC Evolutionary Biology}, keywords = {imported}, month = {01}, note = {WOS:000263055400002}, pages = 16, title = {Sex-specific dispersal and evolutionary rescue in metapopulations infected by male killing endosymbionts}, volume = 9, year = 2009 }

  %0 Journal Article %1 bonte_sex-specific_2009 %A Bonte, Dries %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2009 %J BMC Evolutionary Biology %P 16 %R 10.1186/1471-2148-9-16 %T Sex-specific dispersal and evolutionary rescue in metapopulations infected by male killing endosymbionts %V 9 %X Background: Male killing endosymbionts manipulate their arthropod host reproduction by only allowing female embryos to develop into infected females and killing all male offspring. Because the resulting change in sex ratio is expected to affect the evolution of sex-specific dispersal, we investigated under which environmental conditions strong sex-biased dispersal would emerge, and how this would affect host and endosymbiont metapopulation persistence. Results: We simulated host-endosymbiont metapopulation dynamics in an individual-based model, in which dispersal rates are allowed to evolve independently for the two sexes. Prominent male-biased dispersal emerges under conditions of low environmental stochasticity and high dispersal mortality. By applying a reshuffling algorithm, we show that kin-competition is a major driver of this evolutionary pattern because of the high within-population relatedness of males compared to those of females. Moreover, the evolution of sex-specific dispersal rescues metapopulations from extinction by (i) reducing endosymbiont fixation rates and (ii) by enhancing the extinction of endosymbionts within metapopulations that are characterized by low environmental stochasticity. Conclusion: Male killing endosymbionts induce the evolution of sex-specific dispersal, with prominent male-biased dispersal under conditions of low environmental stochasticity and high dispersal mortality. This male-biased dispersal emerges from stronger kin-competition in males compared to females and induces an evolutionary rescue mechanism.
• Sex-specific spatio-temporal variability in reproductive success promotes the evolution of sex-biased dispersal. Gros, Andreas; Poethke, Hans Joachim; Hovestadt, Thomas. In Theoretical Population Biology, 76(1), pp. 13–18. 2009.
  • [ BibTeX ]
  • [ EndNote ]
  @article{gros_sex-specific_2009, abstract = {Inbreeding depression, asymmetries in costs or benefits of dispersal, and the mating system have been identified as potential factors underlying the evolution of sex-biased dispersal. We use individual-based simulations to explore how the mating system and demographic stochasticity influence the evolution of sex-specific dispersal in a metapopulation with females competing over breeding sites, and males over mating opportunities. Comparison of simulation results for random mating with those for a harem system (locally, a single male sires all offspring) reveal that even extreme variance in local male reproductive success (extreme male competition) does not induce male-biased dispersal. The latter evolves if the between-parch variance in reproductive success is larger for males than females. This can emerge due to demographic stochasticity if the habitat patches are small. More generally, members of a group of individuals experiencing higher spatio-temporal variance in fitness expectations may evolve to disperse with greater probability than others. (C) 2009 Elsevier Inc. All rights reserved.}, author = {Gros, Andreas and Poethke, Hans Joachim and Hovestadt, Thomas}, journal = {Theoretical Population Biology}, keywords = {imported}, month = {08}, note = {WOS:000266944200002}, number = 1, pages = {13–18}, title = {Sex-specific spatio-temporal variability in reproductive success promotes the evolution of sex-biased dispersal}, volume = 76, year = 2009 }

  %0 Journal Article %1 gros_sex-specific_2009 %A Gros, Andreas %A Poethke, Hans Joachim %A Hovestadt, Thomas %D 2009 %J Theoretical Population Biology %N 1 %P 13--18 %R 10.1016/j.tpb.2009.03.002 %T Sex-specific spatio-temporal variability in reproductive success promotes the evolution of sex-biased dispersal %V 76 %X Inbreeding depression, asymmetries in costs or benefits of dispersal, and the mating system have been identified as potential factors underlying the evolution of sex-biased dispersal. We use individual-based simulations to explore how the mating system and demographic stochasticity influence the evolution of sex-specific dispersal in a metapopulation with females competing over breeding sites, and males over mating opportunities. Comparison of simulation results for random mating with those for a harem system (locally, a single male sires all offspring) reveal that even extreme variance in local male reproductive success (extreme male competition) does not induce male-biased dispersal. The latter evolves if the between-parch variance in reproductive success is larger for males than females. This can emerge due to demographic stochasticity if the habitat patches are small. More generally, members of a group of individuals experiencing higher spatio-temporal variance in fitness expectations may evolve to disperse with greater probability than others. (C) 2009 Elsevier Inc. All rights reserved.

• Evolution of sex-biased dispersal: The role of sex-specific dispersal costs, demographic stochasticity, and inbreeding. Gros, Andreas; Hovestadt, Thomas; Poethke, Hans Joachim. In Ecological Modelling, 219(1-2), pp. 226–233. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  @article{gros_evolution_2008, abstract = {Inbreeding avoidance and asymmetric competition over resources have both been identified as factors favoring the evolution of sex-biased dispersal. It has also been recognized that sex-specific costs of dispersal would select for sex-biased dispersal, but there is little quantitative information on this aspect. In this paper we explore (i) the quantitative relationship between cost-asymmetry and a bias in dispersal, (ii) the influence of demographic stochasticity on this effect, and (iii) how inbreeding and cost-asymmetry interact in their effect on sex-specific dispersal. We adjust an existing analytical model to account for sex-specific costs of dispersal. Based on numerical calculations we predict a severe bias in dispersal already for small differences in dispersal costs. We corroborate these predictions in individual-based simulations, but show that demographic stochasticity generally leads to more balanced dispersal. In combination with inbreeding, cost asymmetries will usually determine which of the two sexes becomes the more dispersive. (C) 2008 Elsevier B.V. All rights reserved.}, author = {Gros, Andreas and Hovestadt, Thomas and Poethke, Hans Joachim}, journal = {Ecological Modelling}, keywords = {imported}, month = 11, note = {WOS:000261291900019}, number = {1-2}, pages = {226–233}, title = {Evolution of sex-biased dispersal: {The} role of sex-specific dispersal costs, demographic stochasticity, and inbreeding}, volume = 219, year = 2008 }

  %0 Journal Article %1 gros_evolution_2008 %A Gros, Andreas %A Hovestadt, Thomas %A Poethke, Hans Joachim %D 2008 %J Ecological Modelling %N 1-2 %P 226--233 %R 10.1016/j.ecolmodel.2008.08.014 %T Evolution of sex-biased dispersal: The role of sex-specific dispersal costs, demographic stochasticity, and inbreeding %V 219 %X Inbreeding avoidance and asymmetric competition over resources have both been identified as factors favoring the evolution of sex-biased dispersal. It has also been recognized that sex-specific costs of dispersal would select for sex-biased dispersal, but there is little quantitative information on this aspect. In this paper we explore (i) the quantitative relationship between cost-asymmetry and a bias in dispersal, (ii) the influence of demographic stochasticity on this effect, and (iii) how inbreeding and cost-asymmetry interact in their effect on sex-specific dispersal. We adjust an existing analytical model to account for sex-specific costs of dispersal. Based on numerical calculations we predict a severe bias in dispersal already for small differences in dispersal costs. We corroborate these predictions in individual-based simulations, but show that demographic stochasticity generally leads to more balanced dispersal. In combination with inbreeding, cost asymmetries will usually determine which of the two sexes becomes the more dispersive. (C) 2008 Elsevier B.V. All rights reserved.
• Process and measurement errors of population size: their mutual effects on precision and bias of estimates for demographic parameters. Hovestadt, Thomas; Nowicki, Piotr. In Biodiversity and Conservation, 17(14), pp. 3417–3429. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_process_2008, abstract = {Knowing the parameters of population growth and regulation is fundamental for answering many ecological questions and the successful implementation of conservation strategies. Moreover, detecting a population trend is often a legal obligation. Yet, inherent process and measurement errors aggravate the ability to estimate these parameters from population time-series. We use numerical simulations to explore how the lengths of the time-series, process and measurement error influence estimates of demographic parameters. We first generate time-series of population sizes with given demographic parameters for density-dependent stochastic population growth, but assume that these population sizes are estimated with measurement errors. We then fit parameters for population growth, habitat capacity, total error and long-term trends to the 'measured' time-series data using non-linear regression. The length of the time-series and measurement error introduce a substantial bias in the estimates for population growth rate and to a lesser degree on estimates for habitat capacity, while process error has little effect on parameter bias. The total error term of the statistical model is dominated by process error as long as the latter is larger than the measurement error. A decline in population size is difficult to document as soon as either error becomes moderate, trends are not very pronounced, and time-series are short ({\textless} 10-15 seasons). Detecting an annual decline of 1\% within 6-year reporting periods, as required for the European Union for the species of Community Interest, appears unachievable.}, author = {Hovestadt, Thomas and Nowicki, Piotr}, journal = {Biodiversity and Conservation}, keywords = {imported}, month = 12, note = {WOS:000260938000007}, number = 14, pages = {3417–3429}, title = {Process and measurement errors of population size: their mutual effects on precision and bias of estimates for demographic parameters}, volume = 17, year = 2008 }

  %0 Journal Article %1 hovestadt_process_2008 %A Hovestadt, Thomas %A Nowicki, Piotr %D 2008 %J Biodiversity and Conservation %N 14 %P 3417--3429 %R 10.1007/s10531-008-9426-0 %T Process and measurement errors of population size: their mutual effects on precision and bias of estimates for demographic parameters %V 17 %X Knowing the parameters of population growth and regulation is fundamental for answering many ecological questions and the successful implementation of conservation strategies. Moreover, detecting a population trend is often a legal obligation. Yet, inherent process and measurement errors aggravate the ability to estimate these parameters from population time-series. We use numerical simulations to explore how the lengths of the time-series, process and measurement error influence estimates of demographic parameters. We first generate time-series of population sizes with given demographic parameters for density-dependent stochastic population growth, but assume that these population sizes are estimated with measurement errors. We then fit parameters for population growth, habitat capacity, total error and long-term trends to the 'measured' time-series data using non-linear regression. The length of the time-series and measurement error introduce a substantial bias in the estimates for population growth rate and to a lesser degree on estimates for habitat capacity, while process error has little effect on parameter bias. The total error term of the statistical model is dominated by process error as long as the latter is larger than the measurement error. A decline in population size is difficult to document as soon as either error becomes moderate, trends are not very pronounced, and time-series are short (\textless 10-15 seasons). Detecting an annual decline of 1% within 6-year reporting periods, as required for the European Union for the species of Community Interest, appears unachievable.
• Habitat quality matters for the distribution of an endangered leaf beetle and its egg parasitoid in a fragmented landscape. Heisswolf, Annette; Reichmann, Stefanie; Poethke, Hans Joachim; Schröder, Boris; Obermaier, Elisabeth. In Journal of Insect Conservation, 13(2), pp. 165–175. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{heisswolf_habitat_2008, abstract = {Fragmentation, deterioration, and loss of habitat patches threaten the survival of many insect species. Depending on their trophic level, species may be differently affected by these factors. However, studies investigating more than one trophic level on a landscape scale are still rare. In the present study we analyzed the effects of habitat size, isolation, and quality for the occurrence and population density of the endangered leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) and its egg parasitoid, the hymenopteran wasp Foersterella reptans Nees (Hymenoptera: Tetracampidae). C. canaliculata is strictly monophagous on meadow sage (Salvia pratensis), while F. reptans can also parasitize other hosts. Both size and isolation of habitat patches strongly determined the occurrence of the beetle. However, population density increased to a much greater extent with increasing host plant density ( = habitat quality) than with habitat size. The occurrence probability of the egg parasitoid increased with increasing population density of C. canaliculata. In conclusion, although maintaining large, well-connected patches with high host plant density is surely the major conservation goal for the specialized herbivore C. canaliculata, also small patches with high host plant densities can support viable populations and should thus be conserved. The less specialized parasitoid F. reptans is more likely to be found on patches with high beetle density, while patch size and isolation seem to be less important.}, author = {Heisswolf, Annette and Reichmann, Stefanie and Poethke, Hans Joachim and Schröder, Boris and Obermaier, Elisabeth}, journal = {Journal of Insect Conservation}, keywords = {imported}, month = {01}, number = 2, pages = {165–175}, title = {Habitat quality matters for the distribution of an endangered leaf beetle and its egg parasitoid in a fragmented landscape}, volume = 13, year = 2008 }

  %0 Journal Article %1 heisswolf_habitat_2008 %A Heisswolf, Annette %A Reichmann, Stefanie %A Poethke, Hans Joachim %A Schröder, Boris %A Obermaier, Elisabeth %D 2008 %J Journal of Insect Conservation %N 2 %P 165--175 %R 10.1007/s10841-008-9139-4 %T Habitat quality matters for the distribution of an endangered leaf beetle and its egg parasitoid in a fragmented landscape %U http://link.springer.com/article/10.1007/s10841-008-9139-4 %V 13 %X Fragmentation, deterioration, and loss of habitat patches threaten the survival of many insect species. Depending on their trophic level, species may be differently affected by these factors. However, studies investigating more than one trophic level on a landscape scale are still rare. In the present study we analyzed the effects of habitat size, isolation, and quality for the occurrence and population density of the endangered leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) and its egg parasitoid, the hymenopteran wasp Foersterella reptans Nees (Hymenoptera: Tetracampidae). C. canaliculata is strictly monophagous on meadow sage (Salvia pratensis), while F. reptans can also parasitize other hosts. Both size and isolation of habitat patches strongly determined the occurrence of the beetle. However, population density increased to a much greater extent with increasing host plant density ( = habitat quality) than with habitat size. The occurrence probability of the egg parasitoid increased with increasing population density of C. canaliculata. In conclusion, although maintaining large, well-connected patches with high host plant density is surely the major conservation goal for the specialized herbivore C. canaliculata, also small patches with high host plant densities can support viable populations and should thus be conserved. The less specialized parasitoid F. reptans is more likely to be found on patches with high beetle density, while patch size and isolation seem to be less important.
• Restricted within-habitat movement and time-constrained egg laying of female Maculinea rebeli butterflies. Kőrösi, Ádám; Örvössy, Noémi; Batáry, Péter; Kövér, Szilvia; Peregovits, László. In Oecologia, 156(2), pp. 455–464. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{korosi_restricted_2008, author = {Kőrösi, Ádám and Örvössy, Noémi and Batáry, Péter and Kövér, Szilvia and Peregovits, László}, journal = {Oecologia}, keywords = {imported}, month = {05}, number = 2, pages = {455–464}, title = {Restricted within-habitat movement and time-constrained egg laying of female {Maculinea} rebeli butterflies}, volume = 156, year = 2008 }

  %0 Journal Article %1 korosi_restricted_2008 %A Kőrösi, Ádám %A Örvössy, Noémi %A Batáry, Péter %A Kövér, Szilvia %A Peregovits, László %D 2008 %J Oecologia %N 2 %P 455--464 %R 10.1007/s00442-008-0986-1 %T Restricted within-habitat movement and time-constrained egg laying of female Maculinea rebeli butterflies %U http://link.springer.com/10.1007/s00442-008-0986-1 %V 156
• Male-killing endosymbionts: influence of environmental conditions on persistence of host metapopulation. Bonte, Dries; Hovestadt, Thomas; Poethke, Hans-Joachim. In Bmc Evolutionary Biology, 8, p. 243. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  @article{bonte_male-killing_2008, abstract = {Background: Male killing endosymbionts manipulate their arthropod host reproduction by only allowing female embryos to develop into infected females and killing all male offspring. Because of the reproductive manipulation, we expect them to have an effect on the evolution of host dispersal rates. In addition, male killing endosymbionts are expected to approach fixation when fitness of infected individuals is larger than that of uninfected ones and when transmission from mother to offspring is nearly perfect. They then vanish as the host population crashes. High observed infection rates and among-population variation in natural systems can consequently not be explained if defense mechanisms are absent and when transmission efficiency is perfect. Results: By simulating the host-endosymbiont dynamics in an individual-based metapopulation model we show that male killing endosymbionts increase host dispersal rates. No fitness compensations were built into the model for male killing endosymbionts, but they spread as a group beneficial trait. Host and parasite populations face extinction under panmictic conditions, i.e. conditions that favor the evolution of high dispersal in hosts. On the other hand, deterministic ' curing' (only parasite goes extinct) can occur under conditions of low dispersal, e. g. under low environmental stochasticity and high dispersal mortality. However, high and stable infection rates can be maintained in metapopulations over a considerable spectrum of conditions favoring intermediate levels of dispersal in the host. Conclusion: Male killing endosymbionts without explicit fitness compensation spread as a group selected trait into a metapopulation. Emergent feedbacks through increased evolutionary stable dispersal rates provide an alternative explanation for both, the high male-killing endosymbiont infection rates reported for some natural systems.}, author = {Bonte, Dries and Hovestadt, Thomas and Poethke, Hans-Joachim}, journal = {Bmc Evolutionary Biology}, keywords = {imported}, month = {09}, note = {WOS:000259777900001}, pages = 243, title = {Male-killing endosymbionts: influence of environmental conditions on persistence of host metapopulation}, volume = 8, year = 2008 }

  %0 Journal Article %1 bonte_male-killing_2008 %A Bonte, Dries %A Hovestadt, Thomas %A Poethke, Hans-Joachim %D 2008 %J Bmc Evolutionary Biology %P 243 %R 10.1186/1471-2148-8-243 %T Male-killing endosymbionts: influence of environmental conditions on persistence of host metapopulation %V 8 %X Background: Male killing endosymbionts manipulate their arthropod host reproduction by only allowing female embryos to develop into infected females and killing all male offspring. Because of the reproductive manipulation, we expect them to have an effect on the evolution of host dispersal rates. In addition, male killing endosymbionts are expected to approach fixation when fitness of infected individuals is larger than that of uninfected ones and when transmission from mother to offspring is nearly perfect. They then vanish as the host population crashes. High observed infection rates and among-population variation in natural systems can consequently not be explained if defense mechanisms are absent and when transmission efficiency is perfect. Results: By simulating the host-endosymbiont dynamics in an individual-based metapopulation model we show that male killing endosymbionts increase host dispersal rates. No fitness compensations were built into the model for male killing endosymbionts, but they spread as a group beneficial trait. Host and parasite populations face extinction under panmictic conditions, i.e. conditions that favor the evolution of high dispersal in hosts. On the other hand, deterministic ' curing' (only parasite goes extinct) can occur under conditions of low dispersal, e. g. under low environmental stochasticity and high dispersal mortality. However, high and stable infection rates can be maintained in metapopulations over a considerable spectrum of conditions favoring intermediate levels of dispersal in the host. Conclusion: Male killing endosymbionts without explicit fitness compensation spread as a group selected trait into a metapopulation. Emergent feedbacks through increased evolutionary stable dispersal rates provide an alternative explanation for both, the high male-killing endosymbiont infection rates reported for some natural systems.
• Variation of dispersal agents? Frugivore assemblages and fruit handling in a typical ’bird-dispersed’ tree (Lannea acida, {Anacardiaceae}). Kunz, Britta K.; Hovestadt, Thomas; Linsenmair, K. Eduard. In Ecotropica-Bonn, 14(2), pp. 101–112. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  @article{kunz_variation_2008, abstract = {Particular combinations of traits related to the consumption of fruits and dispersal of seeds by specific groups Of frugivores have led to the postulation of 'dispersal syndromes'. Lannea acida (Anacardiaceae) is a West African tree with small purple drupes characteristic of the bird-dispersal syndrome. Given fruit type and size, however, the fruits should be attractive to a wider range of arboreal frugivores. To test this, we monitored frugivore assemblages, feeding activity during crop maturation, and fruit handling by frugivores. Fruits were harvested by}, author = {Kunz, Britta K. and Hovestadt, Thomas and Linsenmair, K. Eduard}, journal = {Ecotropica-Bonn}, keywords = {imported}, note = {BIOSIS:PREV200900201168}, number = 2, pages = {101–112}, title = {Variation of dispersal agents? {Frugivore} assemblages and fruit handling in a typical 'bird-dispersed' tree ({Lannea} acida, {Anacardiaceae})}, volume = 14, year = 2008 }

  %0 Journal Article %1 kunz_variation_2008 %A Kunz, Britta K. %A Hovestadt, Thomas %A Linsenmair, K. Eduard %D 2008 %J Ecotropica-Bonn %N 2 %P 101--112 %T Variation of dispersal agents? Frugivore assemblages and fruit handling in a typical 'bird-dispersed' tree (Lannea acida, {Anacardiaceae}) %V 14 %X Particular combinations of traits related to the consumption of fruits and dispersal of seeds by specific groups Of frugivores have led to the postulation of 'dispersal syndromes'. Lannea acida (Anacardiaceae) is a West African tree with small purple drupes characteristic of the bird-dispersal syndrome. Given fruit type and size, however, the fruits should be attractive to a wider range of arboreal frugivores. To test this, we monitored frugivore assemblages, feeding activity during crop maturation, and fruit handling by frugivores. Fruits were harvested by
• Species-specific distribution of two sympatric Maculinea butterflies across different meadow edges. Batáry, Péter; Kőrösi, Ádám; Örvössy, Noémi; Kövér, Szilvia; Peregovits, László. In Journal of Insect Conservation, 13(2), pp. 223–230. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{batary_species-specific_2008, abstract = {An important consequence of habitat fragmentation is the increase of edge habitats. Environmental factors in the edges are different from those in the interiors, which causes changes in the distribution of plant and animal species. We aimed to study how edges affect the distribution of two butterfly species within meadow fragments. We therefore investigated the effect of distance from edge and edge type (road edge versus tree edge) on two sympatric large blue species (Maculinea teleius and M. nausithous). Our results showed that edge type had contrasting effects on the two species. M. teleius favoured both interiors and road edges, while M. nausithous preferred the tree edges. In the case of the latter species a strong positive edge effect was also found. This kind of within-habitat niche segregation is probably related to the different microenvironmental conditions at the edges. Foodplant density did not seem to limit the distribution of these species. Our results suggest that interiors of meadows are important for M. teleius, while tree edges maintain the habitats of the regionally rarer butterfly, M. nausithous.}, author = {Batáry, Péter and Kőrösi, Ádám and Örvössy, Noémi and Kövér, Szilvia and Peregovits, László}, journal = {Journal of Insect Conservation}, keywords = {imported}, month = {03}, number = 2, pages = {223–230}, title = {Species-specific distribution of two sympatric {Maculinea} butterflies across different meadow edges}, volume = 13, year = 2008 }

  %0 Journal Article %1 batary_species-specific_2008 %A Batáry, Péter %A Kőrösi, Ádám %A Örvössy, Noémi %A Kövér, Szilvia %A Peregovits, László %D 2008 %J Journal of Insect Conservation %N 2 %P 223--230 %R 10.1007/s10841-008-9158-1 %T Species-specific distribution of two sympatric Maculinea butterflies across different meadow edges %U http://link.springer.com/article/10.1007/s10841-008-9158-1 %V 13 %X An important consequence of habitat fragmentation is the increase of edge habitats. Environmental factors in the edges are different from those in the interiors, which causes changes in the distribution of plant and animal species. We aimed to study how edges affect the distribution of two butterfly species within meadow fragments. We therefore investigated the effect of distance from edge and edge type (road edge versus tree edge) on two sympatric large blue species (Maculinea teleius and M. nausithous). Our results showed that edge type had contrasting effects on the two species. M. teleius favoured both interiors and road edges, while M. nausithous preferred the tree edges. In the case of the latter species a strong positive edge effect was also found. This kind of within-habitat niche segregation is probably related to the different microenvironmental conditions at the edges. Foodplant density did not seem to limit the distribution of these species. Our results suggest that interiors of meadows are important for M. teleius, while tree edges maintain the habitats of the regionally rarer butterfly, M. nausithous.
• Egg distribution of the southern festoon (Zerynthia polyxena)(Lepidoptera, {Papilionidae}). Batáry, P.; Örvössy, N.; Kőrösi, Á; Peregovits, L. In Acta Zoologica Academiae Scientarum Hungaricae, 54, pp. 401–410. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{batary_egg_2008, author = {Batáry, P. and Örvössy, N. and Kőrösi, Á and Peregovits, L.}, journal = {Acta Zoologica Academiae Scientarum Hungaricae}, keywords = {imported}, pages = {401–410}, title = {Egg distribution of the southern festoon ({Zerynthia} polyxena)({Lepidoptera}, {Papilionidae})}, volume = 54, year = 2008 }

  %0 Journal Article %1 batary_egg_2008 %A Batáry, P. %A Örvössy, N. %A Kőrösi, Á %A Peregovits, L. %D 2008 %J Acta Zoologica Academiae Scientarum Hungaricae %P 401--410 %T Egg distribution of the southern festoon (Zerynthia polyxena)(Lepidoptera, {Papilionidae}) %U http://134.76.21.39/goescholar/handle/1/7786 %V 54
• Investigating movement within irregularly shaped patches: Analysis of mark-release-recapture data using randomization procedures. Hovestadt, Thomas; Nowicki, Piotr. In Israel Journal of Ecology & Evolution, 54(1), pp. 137–154. 2008.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_investigating_2008, abstract = {The analysis of net-displacement data extracted from mark-release-recapture (MRR) Studies is usually based on the assumption that movement follows a random walk in homogeneous space. Yet given sufficient time, within-patch movement cannot conform to this assumption, as maximum net-displacement must be limited by the patch's dimension. We thus suggest a pragmatic protocol for analyzing such MRR data: (1) Test for correlation between the time intervals between captures and displacement distance; if such a correlation is weak, displacement does not follow the rules of a random walk. (2) Test whether net-displacement observed approaches an even density distribution (null-model). (3) Estimate whether net-displacement is limited by the individual's tendency to restrict movement to sub-regions of a patch. For this purpose we developed two randomization algorithms that generate patch-specific distance distributions given that (i) displacement distances converge to an even distribution and habitat use is homogeneous within patches, or that (ii) the spatial distribution of capture points is heterogeneous. Both methods are expanded to account for the influence of potential movement restrictions beyond those imposed by the patch's dimension. The sequential comparison of empirical distributions with distributions generated by these algorithms allows drawing conclusions about the rules underlying withinpatch movement. We exemplarily apply our protocol to an empirical MRR data set on the butterfly Maculinea teleius. The analysis indicates that habitat use within patches is heterogeneous and that Maculinea possibly establishes home ranges. Such analyses may convey important information about the biology of species and help to develop appropriate conservation strategies.}, author = {Hovestadt, Thomas and Nowicki, Piotr}, journal = {Israel Journal of Ecology \& Evolution}, keywords = {MaMan}, note = {WOS:000257257300010}, number = 1, pages = {137–154}, title = {Investigating movement within irregularly shaped patches: {Analysis} of mark-release-recapture data using randomization procedures}, volume = 54, year = 2008 }

  %0 Journal Article %1 hovestadt_investigating_2008 %A Hovestadt, Thomas %A Nowicki, Piotr %D 2008 %J Israel Journal of Ecology & Evolution %N 1 %P 137--154 %R 10.1560/IJEE.54.1.137 %T Investigating movement within irregularly shaped patches: Analysis of mark-release-recapture data using randomization procedures %V 54 %X The analysis of net-displacement data extracted from mark-release-recapture (MRR) Studies is usually based on the assumption that movement follows a random walk in homogeneous space. Yet given sufficient time, within-patch movement cannot conform to this assumption, as maximum net-displacement must be limited by the patch's dimension. We thus suggest a pragmatic protocol for analyzing such MRR data: (1) Test for correlation between the time intervals between captures and displacement distance; if such a correlation is weak, displacement does not follow the rules of a random walk. (2) Test whether net-displacement observed approaches an even density distribution (null-model). (3) Estimate whether net-displacement is limited by the individual's tendency to restrict movement to sub-regions of a patch. For this purpose we developed two randomization algorithms that generate patch-specific distance distributions given that (i) displacement distances converge to an even distribution and habitat use is homogeneous within patches, or that (ii) the spatial distribution of capture points is heterogeneous. Both methods are expanded to account for the influence of potential movement restrictions beyond those imposed by the patch's dimension. The sequential comparison of empirical distributions with distributions generated by these algorithms allows drawing conclusions about the rules underlying withinpatch movement. We exemplarily apply our protocol to an empirical MRR data set on the butterfly Maculinea teleius. The analysis indicates that habitat use within patches is heterogeneous and that Maculinea possibly establishes home ranges. Such analyses may convey important information about the biology of species and help to develop appropriate conservation strategies.

• Mosaic cycles in agricultural landscapes of Northwest Europe. Kleyer, Michael; Biedermann, Robert; Henle, Klaus; Obermaier, Elisabeth; Poethke, Hans-Joachim; Poschlod, Peter; Schröder, Boris; Settele, Josef; Vetterlein, Doris. In Basic and Applied Ecology, 8(4), pp. 295–309. 2007.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{kleyer_mosaic_2007, abstract = {Mosaic cycles were originally understood as cyclical regeneration phases in forests. In this review, we shall examine how far the concept can be extended towards cyclical mosaics of habitat quality in patterned landscapes as a special case of ‘dynamic landscapes’. We will concentrate on habitats and plants in European temperate agricultural landscapes and grasslands in particular. Mosaic cycles of habitat quality are characterised by spatiotemporal shifts between disturbance and secondary succession. We found evidence for mosaic cycles in traditional agricultural systems, modern crop farming, and in recent conservation management. The relevant disturbance parameters to describe land-use drivers of mosaic cycles are spatial extent, frequency, and magnitude (biomass loss). Land-use-related drivers are usually regular and deterministic in space and time, with the exception of year-round grazing by free-ranging large herbivores. Fluctuating soil resources such as water and nutrients in interaction with climate variability add a stochastic component to these (land-use-related) drivers. The proportion of deterministic and stochastic components and their autocorrelation in time and space divides purely deterministic mosaic cycles from purely stochastic dynamic landscapes. In a second part, we briefly review plant life-history traits that may facilitate survival of plants in mosaic cycles of habitat quality. Theoretical studies emphasise (i) dispersal functions for extinction and recolonisation processes of metapopulations, (ii) storage effects as a component of buffered population growth in response to temporal fluctuations of habitat quality, and (iii) competitive ability in metacommunities. We propose a simple scheme relating these functions to the temporal and spatial correlation of patterned landscapes. There are only a very limited number of field studies available that give some support for the proposed scheme. We provide perspectives for further research in this field.}, author = {Kleyer, Michael and Biedermann, Robert and Henle, Klaus and Obermaier, Elisabeth and Poethke, Hans-Joachim and Poschlod, Peter and Schröder, Boris and Settele, Josef and Vetterlein, Doris}, journal = {Basic and Applied Ecology}, keywords = {quality,}, month = {07}, number = 4, pages = {295–309}, title = {Mosaic cycles in agricultural landscapes of {Northwest} {Europe}}, volume = 8, year = 2007 }

  %0 Journal Article %1 kleyer_mosaic_2007 %A Kleyer, Michael %A Biedermann, Robert %A Henle, Klaus %A Obermaier, Elisabeth %A Poethke, Hans-Joachim %A Poschlod, Peter %A Schröder, Boris %A Settele, Josef %A Vetterlein, Doris %D 2007 %J Basic and Applied Ecology %N 4 %P 295--309 %R 10.1016/j.baae.2007.02.002 %T Mosaic cycles in agricultural landscapes of Northwest Europe %U http://www.sciencedirect.com/science/article/pii/S1439179107000163 %V 8 %X Mosaic cycles were originally understood as cyclical regeneration phases in forests. In this review, we shall examine how far the concept can be extended towards cyclical mosaics of habitat quality in patterned landscapes as a special case of ‘dynamic landscapes’. We will concentrate on habitats and plants in European temperate agricultural landscapes and grasslands in particular. Mosaic cycles of habitat quality are characterised by spatiotemporal shifts between disturbance and secondary succession. We found evidence for mosaic cycles in traditional agricultural systems, modern crop farming, and in recent conservation management. The relevant disturbance parameters to describe land-use drivers of mosaic cycles are spatial extent, frequency, and magnitude (biomass loss). Land-use-related drivers are usually regular and deterministic in space and time, with the exception of year-round grazing by free-ranging large herbivores. Fluctuating soil resources such as water and nutrients in interaction with climate variability add a stochastic component to these (land-use-related) drivers. The proportion of deterministic and stochastic components and their autocorrelation in time and space divides purely deterministic mosaic cycles from purely stochastic dynamic landscapes. In a second part, we briefly review plant life-history traits that may facilitate survival of plants in mosaic cycles of habitat quality. Theoretical studies emphasise (i) dispersal functions for extinction and recolonisation processes of metapopulations, (ii) storage effects as a component of buffered population growth in response to temporal fluctuations of habitat quality, and (iii) competitive ability in metacommunities. We propose a simple scheme relating these functions to the temporal and spatial correlation of patterned landscapes. There are only a very limited number of field studies available that give some support for the proposed scheme. We provide perspectives for further research in this field.
• Microhabitat preferences of Maculinea teleius (Lepidoptera: {Lycaenidae}) in a mosaic landscape. Batáry, Péter; Örvössy, Noémi; Kőrösi, Ádám; Nagy, Marianna Vályi; Peregovits, László. In European Journal of Entomology, 104(4), p. 731. 2007.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{batary_microhabitat_2007, author = {Batáry, Péter and Örvössy, Noémi and Kőrösi, Ádám and Nagy, Marianna Vályi and Peregovits, László}, journal = {European Journal of Entomology}, keywords = {imported}, number = 4, pages = 731, title = {Microhabitat preferences of {Maculinea} teleius ({Lepidoptera}: {Lycaenidae}) in a mosaic landscape}, volume = 104, year = 2007 }

  %0 Journal Article %1 batary_microhabitat_2007 %A Batáry, Péter %A Örvössy, Noémi %A Kőrösi, Ádám %A Nagy, Marianna Vályi %A Peregovits, László %D 2007 %J European Journal of Entomology %N 4 %P 731 %T Microhabitat preferences of Maculinea teleius (Lepidoptera: {Lycaenidae}) in a mosaic landscape %U http://search.proquest.com/openview/ec966137122513995aeb1879600dcbed/1?pq-origsite=gscholar %V 104
• Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small-scale movement behaviour. Heisswolf, Annette; Ulmann, Sandra; Obermaier, Elisabeth; Mitesser, Oliver; Poethke, Hans Joachim. In Ecological Entomology, 32, pp. 194–200. 2007.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{HEISSWOLF:April2007:0307-6946:194, abstract = {. 1.Host plant finding in walking herbivorous beetles is still poorly understood. Analysis of small-scale movement patterns under semi-natural conditions can be a useful tool to detect behavioural responses towards host plant cues.2.In this study, the small-scale movement behaviour of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) was studied in a semi-natural arena (r 1 m). In three different settings, a host (Salvia pratensis L., Lamiales: Lamiaceae), a non-host (Rumex conglomeratus Murr., Caryophyllales: Polygonaceae), or no plant was presented in the centre of the arena. 3.The beetles showed no differences in the absolute movement variables, straightness and mean walking speed, between the three settings. However, the relative movement variables, mean distance to the centre and mean angular deviation from walking straight to the centre, were significantly smaller when a host plant was offered. Likewise, the angular deviation from walking straight to the centre tended to decline with decreasing distance from the centre. Finally, significantly more beetles were found on the host than on the non-host at the end of all the trials.4.It is concluded that C. canaliculata is able to recognise its host plant from a distance. Whether olfactory or visual cues (or a combination of both) are used to find the host plant remains to be elucidated by further studies.}, author = {Heisswolf, Annette and Ulmann, Sandra and Obermaier, Elisabeth and Mitesser, Oliver and Poethke, Hans Joachim}, journal = {Ecological Entomology}, keywords = {olivervinzenzmitesser}, pages = {194-200}, title = {Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small-scale movement behaviour}, volume = 32, year = 2007 }

  %0 Journal Article %1 HEISSWOLF:April2007:0307-6946:194 %A Heisswolf, Annette %A Ulmann, Sandra %A Obermaier, Elisabeth %A Mitesser, Oliver %A Poethke, Hans Joachim %D 2007 %J Ecological Entomology %P 194-200 %R doi:10.1111/j.1365-2311.2006.00858.x %T Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small-scale movement behaviour %U http://www.ingentaconnect.com/content/bsc/eent/2007/00000032/00000002/art00008 %V 32 %X . 1.Host plant finding in walking herbivorous beetles is still poorly understood. Analysis of small-scale movement patterns under semi-natural conditions can be a useful tool to detect behavioural responses towards host plant cues.2.In this study, the small-scale movement behaviour of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) was studied in a semi-natural arena (r 1 m). In three different settings, a host (Salvia pratensis L., Lamiales: Lamiaceae), a non-host (Rumex conglomeratus Murr., Caryophyllales: Polygonaceae), or no plant was presented in the centre of the arena. 3.The beetles showed no differences in the absolute movement variables, straightness and mean walking speed, between the three settings. However, the relative movement variables, mean distance to the centre and mean angular deviation from walking straight to the centre, were significantly smaller when a host plant was offered. Likewise, the angular deviation from walking straight to the centre tended to decline with decreasing distance from the centre. Finally, significantly more beetles were found on the host than on the non-host at the end of all the trials.4.It is concluded that C. canaliculata is able to recognise its host plant from a distance. Whether olfactory or visual cues (or a combination of both) are used to find the host plant remains to be elucidated by further studies.
• An evolutionarily stable strategy model for the evolution of dimorphic development in the butterfly Maculinea rebeli, a social parasite of Myrmica ant colonies. Hovestadt, Thomas; Mitesser, Oliver; Elmes, Graham W.; Thomas, Jeremy A.; Hochberg, Michael E. In American Naturalist, 169(4), pp. 466–480. 2007.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_evolutionarily_2007, abstract = {Caterpillars of the butterfly Maculinea rebeli develop as parasites inside ant colonies. In intensively studied French populations, about 25\% of caterpillars mature within 1 year (fast-developing larvae [FDL]) and the others after 2 years (slow-developing larvae [SDL]); all available evidence indicates that this ratio is under the control of egg-laying females. We present an analytical model to predict the evolutionarily stable fraction of FDL (P-ess). The model accounts for added winter mortality of SDL, general and kin competition among caterpillars, a competitive advantage of SDL over newly entering FDL (priority effect), and the avoidance of renewed infection of ant nests by butterflies in the coming season (segregation). We come to the following conclusions: (1) all factors listed above can promote the evolution of delayed development; (2) kin competition and segregation stabilize P-ess near 0.5; and (3) a priority effect is the only mechanism potentially selecting for P-ess {\textless} 0.5. However, given the empirical data, p ESS is predicted to fall closer to 0.5 than to the 0.25 that has been observed. In this particular system, bet hedging cannot explain why more than 50\% of larvae postpone growth. Presumably, other fitness benefits for SDL, for example, higher fertility or longevity, also contribute to the evolution of delayed development. The model presented here may be of general applicability for systems where maturing individuals compete in small subgroups.}, author = {Hovestadt, Thomas and Mitesser, Oliver and Elmes, Graham W. and Thomas, Jeremy A. and Hochberg, Michael E.}, journal = {American Naturalist}, keywords = {olivervinzenzmitesser}, month = {04}, note = {WOS:000245028000007}, number = 4, pages = {466–480}, title = {An evolutionarily stable strategy model for the evolution of dimorphic development in the butterfly {Maculinea} rebeli, a social parasite of {Myrmica} ant colonies}, volume = 169, year = 2007 }

  %0 Journal Article %1 hovestadt_evolutionarily_2007 %A Hovestadt, Thomas %A Mitesser, Oliver %A Elmes, Graham W. %A Thomas, Jeremy A. %A Hochberg, Michael E. %D 2007 %J American Naturalist %N 4 %P 466--480 %R 10.1086/512134 %T An evolutionarily stable strategy model for the evolution of dimorphic development in the butterfly Maculinea rebeli, a social parasite of Myrmica ant colonies %V 169 %X Caterpillars of the butterfly Maculinea rebeli develop as parasites inside ant colonies. In intensively studied French populations, about 25% of caterpillars mature within 1 year (fast-developing larvae [FDL]) and the others after 2 years (slow-developing larvae [SDL]); all available evidence indicates that this ratio is under the control of egg-laying females. We present an analytical model to predict the evolutionarily stable fraction of FDL (P-ess). The model accounts for added winter mortality of SDL, general and kin competition among caterpillars, a competitive advantage of SDL over newly entering FDL (priority effect), and the avoidance of renewed infection of ant nests by butterflies in the coming season (segregation). We come to the following conclusions: (1) all factors listed above can promote the evolution of delayed development; (2) kin competition and segregation stabilize P-ess near 0.5; and (3) a priority effect is the only mechanism potentially selecting for P-ess textless 0.5. However, given the empirical data, p ESS is predicted to fall closer to 0.5 than to the 0.25 that has been observed. In this particular system, bet hedging cannot explain why more than 50% of larvae postpone growth. Presumably, other fitness benefits for SDL, for example, higher fertility or longevity, also contribute to the evolution of delayed development. The model presented here may be of general applicability for systems where maturing individuals compete in small subgroups.
• The generality of habitat suitability models: A practical test with two insect groups. Hein, Silke; Binzenhöfer, Birgit; Poethke, Hans-Joachim; Biedermann, Robert; Settele, Josef; Schröder, Boris. In Basic and Applied Ecology, 8(4), pp. 310–320. 2007.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{hein_generality_2007, abstract = {Summary For the design and declaration of conservation areas as well as for planning habitat management it is important to quantitatively know the habitat preferences of the focal species. To take into account the requirements of as many species as possible, it would be of great advantage if one would either (i) find one or several species whose habitat requirements cover those of a large number of other species or if one could (ii) identify a common set of habitat parameters that is important for the occurrence of many species. Ideally such common habitat parameters should be easy to measure. Only then they may be of practical value in applied conservation biology. In this study, we compared the habitat preferences of different insect species (grasshoppers, bush crickets, butterflies, moths) in the same region by applying identical methods. To identify common explanatory variables that predict the occurrence probability of these species, we first tested the transferability of the specific ‘species models’ to other species within the same insect group. We tested how well the incidence of one species can be predicted by the occurrence probability of another species. The ‘best’ models within each group were then tested for transferability between the different groups. Additionally, we tested the predictive power of the predictor variable ‘habitat type’ as an easy and often available measure for conservation practice. Although in the different ‘species models’ different key factors determine habitat suitability, some models were successfully transferred and were able to reasonably predict the distribution of other species. The habitat preferences of the burnet moth Zygaena carniolica were particularly well suited for the prediction of suitable habitats for all other species. In addition, the predictor variable ‘habitat type’ played a dominant role in all models. Models using this aggregated predictor variable may well predict suitable habitat for all species.}, author = {Hein, Silke and Binzenhöfer, Birgit and Poethke, Hans-Joachim and Biedermann, Robert and Settele, Josef and Schröder, Boris}, journal = {Basic and Applied Ecology}, keywords = {Umbrella}, month = {07}, number = 4, pages = {310–320}, title = {The generality of habitat suitability models: {A} practical test with two insect groups}, volume = 8, year = 2007 }

  %0 Journal Article %1 hein_generality_2007 %A Hein, Silke %A Binzenhöfer, Birgit %A Poethke, Hans-Joachim %A Biedermann, Robert %A Settele, Josef %A Schröder, Boris %D 2007 %J Basic and Applied Ecology %N 4 %P 310--320 %R 10.1016/j.baae.2006.09.012 %T The generality of habitat suitability models: A practical test with two insect groups %U http://www.sciencedirect.com/science/article/pii/S1439179106000995 %V 8 %X Summary For the design and declaration of conservation areas as well as for planning habitat management it is important to quantitatively know the habitat preferences of the focal species. To take into account the requirements of as many species as possible, it would be of great advantage if one would either (i) find one or several species whose habitat requirements cover those of a large number of other species or if one could (ii) identify a common set of habitat parameters that is important for the occurrence of many species. Ideally such common habitat parameters should be easy to measure. Only then they may be of practical value in applied conservation biology. In this study, we compared the habitat preferences of different insect species (grasshoppers, bush crickets, butterflies, moths) in the same region by applying identical methods. To identify common explanatory variables that predict the occurrence probability of these species, we first tested the transferability of the specific ‘species models’ to other species within the same insect group. We tested how well the incidence of one species can be predicted by the occurrence probability of another species. The ‘best’ models within each group were then tested for transferability between the different groups. Additionally, we tested the predictive power of the predictor variable ‘habitat type’ as an easy and often available measure for conservation practice. Although in the different ‘species models’ different key factors determine habitat suitability, some models were successfully transferred and were able to reasonably predict the distribution of other species. The habitat preferences of the burnet moth Zygaena carniolica were particularly well suited for the prediction of suitable habitats for all other species. In addition, the predictor variable ‘habitat type’ played a dominant role in all models. Models using this aggregated predictor variable may well predict suitable habitat for all species.
• Consequences of cyclic vegetation management for arthropod survival: Simulation experiments. Hinsch, Martin; Poethke, Hans-Joachim. In Basic and Applied Ecology, 8(4), pp. 321–331. 2007.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{hinsch_consequences_2007, abstract = {Summary Many rare arthropod species occupy open grasslands. Mowing or grazing is needed to preserve the habitat for these species. Alternatively the vegetation cover in parts of the managed area can be periodically destroyed by ploughing or rototilling. Such treatment results in a dynamic mosaic of habitat patches in different stages of succession. This mosaic may serve as a habitat for many species. However, the interplay between the frequency of rototilling, the spatial structure of the landscape and life history attributes of the animal species will determine the success of such cyclic management strategies. We used a spatially implicit individual-based metapopulation model to examine optimal spatio-temporal management strategies. The model explicitly incorporates succession, population dynamics and dispersal between habitat patches. Optimal management patterns strongly depend on the species’ properties. Our simulation experiments show that in general the more fertile species with strong intraspecific competition are most robust against the large fluctuations of habitat quality resulting from cyclic management. However, the best management strategies found in our experiments cover the requirements of up to 70\% of the species tested. Frequent management of relatively small sub-areas minimizes local fluctiations of patch capacity. Though reducing effective patch capacity by more than 50\% these strategies may support the survival of the majority of species.}, author = {Hinsch, Martin and Poethke, Hans-Joachim}, journal = {Basic and Applied Ecology}, keywords = {Life}, month = {07}, number = 4, pages = {321–331}, title = {Consequences of cyclic vegetation management for arthropod survival: {Simulation} experiments}, volume = 8, year = 2007 }

  %0 Journal Article %1 hinsch_consequences_2007 %A Hinsch, Martin %A Poethke, Hans-Joachim %D 2007 %J Basic and Applied Ecology %N 4 %P 321--331 %R 10.1016/j.baae.2006.09.011 %T Consequences of cyclic vegetation management for arthropod survival: Simulation experiments %U http://www.sciencedirect.com/science/article/pii/S1439179106000983 %V 8 %X Summary Many rare arthropod species occupy open grasslands. Mowing or grazing is needed to preserve the habitat for these species. Alternatively the vegetation cover in parts of the managed area can be periodically destroyed by ploughing or rototilling. Such treatment results in a dynamic mosaic of habitat patches in different stages of succession. This mosaic may serve as a habitat for many species. However, the interplay between the frequency of rototilling, the spatial structure of the landscape and life history attributes of the animal species will determine the success of such cyclic management strategies. We used a spatially implicit individual-based metapopulation model to examine optimal spatio-temporal management strategies. The model explicitly incorporates succession, population dynamics and dispersal between habitat patches. Optimal management patterns strongly depend on the species’ properties. Our simulation experiments show that in general the more fertile species with strong intraspecific competition are most robust against the large fluctuations of habitat quality resulting from cyclic management. However, the best management strategies found in our experiments cover the requirements of up to 70% of the species tested. Frequent management of relatively small sub-areas minimizes local fluctiations of patch capacity. Though reducing effective patch capacity by more than 50% these strategies may support the survival of the majority of species.
• Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small-scale movement behaviour. Heisswolf, Annette; Ulmann, Sandra; Obermaier, Elisabeth; Mitesser, Oliver; Poethke, Hans Joachim. In Ecological Entomology, 32(2), pp. 194–200. 2007.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{heisswolf_host_2007, abstract = {Abstract 1. Host plant finding in walking herbivorous beetles is still poorly understood. Analysis of small-scale movement patterns under semi-natural conditions can be a useful tool to detect behavioural responses towards host plant cues. 2. In this study, the small-scale movement behaviour of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) was studied in a semi-natural arena (r = 1 m). In three different settings, a host (Salvia pratensis L., Lamiales: Lamiaceae), a non-host (Rumex conglomeratus Murr., Caryophyllales: Polygonaceae), or no plant was presented in the centre of the arena. 3. The beetles showed no differences in the absolute movement variables, straightness and mean walking speed, between the three settings. However, the relative movement variables, mean distance to the centre and mean angular deviation from walking straight to the centre, were significantly smaller when a host plant was offered. Likewise, the angular deviation from walking straight to the centre tended to decline with decreasing distance from the centre. Finally, significantly more beetles were found on the host than on the non-host at the end of all the trials. 4. It is concluded that C. canaliculata is able to recognise its host plant from a distance. Whether olfactory or visual cues (or a combination of both) are used to find the host plant remains to be elucidated by further studies.}, author = {Heisswolf, Annette and Ulmann, Sandra and Obermaier, Elisabeth and Mitesser, Oliver and Poethke, Hans Joachim}, journal = {Ecological Entomology}, keywords = {experiment,}, number = 2, pages = {194–200}, title = {Host plant finding in the specialised leaf beetle {Cassida} canaliculata: an analysis of small-scale movement behaviour}, volume = 32, year = 2007 }

  %0 Journal Article %1 heisswolf_host_2007 %A Heisswolf, Annette %A Ulmann, Sandra %A Obermaier, Elisabeth %A Mitesser, Oliver %A Poethke, Hans Joachim %D 2007 %J Ecological Entomology %N 2 %P 194--200 %R 10.1111/j.1365-2311.2006.00858.x %T Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small-scale movement behaviour %U http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2311.2006.00858.x/abstract %V 32 %X Abstract 1. Host plant finding in walking herbivorous beetles is still poorly understood. Analysis of small-scale movement patterns under semi-natural conditions can be a useful tool to detect behavioural responses towards host plant cues. 2. In this study, the small-scale movement behaviour of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) was studied in a semi-natural arena (r = 1 m). In three different settings, a host (Salvia pratensis L., Lamiales: Lamiaceae), a non-host (Rumex conglomeratus Murr., Caryophyllales: Polygonaceae), or no plant was presented in the centre of the arena. 3. The beetles showed no differences in the absolute movement variables, straightness and mean walking speed, between the three settings. However, the relative movement variables, mean distance to the centre and mean angular deviation from walking straight to the centre, were significantly smaller when a host plant was offered. Likewise, the angular deviation from walking straight to the centre tended to decline with decreasing distance from the centre. Finally, significantly more beetles were found on the host than on the non-host at the end of all the trials. 4. It is concluded that C. canaliculata is able to recognise its host plant from a distance. Whether olfactory or visual cues (or a combination of both) are used to find the host plant remains to be elucidated by further studies.

• Evolution of local adaptations in dispersal strategies. Gros, Andreas; Poethke, Hans Joachim; Hovestadt, Thomas. In Oikos, 114(3), pp. 544–552. 2006.
  • [ BibTeX ]
  • [ EndNote ]
  @article{gros_evolution_2006, abstract = {The optimal probability and distance of dispersal largely depend on the risk to end up in unsuitable habitat. This risk is highest close to the habitat's edge and consequently, optimal dispersal probability and distance should decline towards the habitat's border. This selection should lead to the emergence of spatial gradients in dispersal strategies. However, gene flow caused by dispersal itself is counteracting local adaptation. Using an individual based model we investigate the evolution of local adaptations of dispersal probability and distance within a single, circular, habitat patch. We compare evolved dispersal probabilities and distances for six different dispersal kernels (two negative exponential kernels, two skewed kernels, nearest neighbour dispersal and global dispersal) in patches of different size. For all kernels a positive correlation between patch size and dispersal probability emerges. However, a minimum patch size is necessary to allow for local adaptation of dispersal strategies within patches. Beyond this minimum patch area the difference in mean dispersal distance between center and edge increases linearly with patch radius, but the intensity of local adaptation depends on the dispersal kernel. Except for global and nearest neighbour dispersal, the evolved spatial pattern are qualitatively similar for both, mean dispersal probability and distance. We conclude, that inspite of the gene-flow originating from dispersal local adaptation of dispersal strategies is possible if a habitat is of sufficient size. This presumably holds for any realistic type of dispersal kernel.}, author = {Gros, Andreas and Poethke, Hans Joachim and Hovestadt, Thomas}, journal = {Oikos}, keywords = {imported}, month = {09}, note = {WOS:000239988300015}, number = 3, pages = {544–552}, title = {Evolution of local adaptations in dispersal strategies}, volume = 114, year = 2006 }

  %0 Journal Article %1 gros_evolution_2006 %A Gros, Andreas %A Poethke, Hans Joachim %A Hovestadt, Thomas %D 2006 %J Oikos %N 3 %P 544--552 %R 10.1111/j.2006.0030-1299.14909.x %T Evolution of local adaptations in dispersal strategies %V 114 %X The optimal probability and distance of dispersal largely depend on the risk to end up in unsuitable habitat. This risk is highest close to the habitat's edge and consequently, optimal dispersal probability and distance should decline towards the habitat's border. This selection should lead to the emergence of spatial gradients in dispersal strategies. However, gene flow caused by dispersal itself is counteracting local adaptation. Using an individual based model we investigate the evolution of local adaptations of dispersal probability and distance within a single, circular, habitat patch. We compare evolved dispersal probabilities and distances for six different dispersal kernels (two negative exponential kernels, two skewed kernels, nearest neighbour dispersal and global dispersal) in patches of different size. For all kernels a positive correlation between patch size and dispersal probability emerges. However, a minimum patch size is necessary to allow for local adaptation of dispersal strategies within patches. Beyond this minimum patch area the difference in mean dispersal distance between center and edge increases linearly with patch radius, but the intensity of local adaptation depends on the dispersal kernel. Except for global and nearest neighbour dispersal, the evolved spatial pattern are qualitatively similar for both, mean dispersal probability and distance. We conclude, that inspite of the gene-flow originating from dispersal local adaptation of dispersal strategies is possible if a habitat is of sufficient size. This presumably holds for any realistic type of dispersal kernel.
• Parameterizing, evaluating and comparing metapopulation models with data from individual-based simulations. Hilker, Frank M.; Hinsch, Martin; Poethke, Hans Joachim. In Ecological Modelling, 199(4), pp. 476–485. 2006.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{hilker_parameterizing_2006, abstract = {Due to the lack of sufficient data and appropriate ecological information parameterizing predictive population dynamical models usually is a difficult task. The approach proposed in this study is meant to overcome this problem by using detailed individual-based simulations to generate artificial data. With short-term data samples, the models to be investigated can be parameterized and their predictions be compared. The flexibility of individual-based simulations as experimental tools also facilitates the evaluation and comparison of different (aggregated) model types. The presented approach is a step towards unifying models of different complexity. As an example we applied it to two metapopulation models of insect species in a highly fragmented landscape: the well-known incidence function model with a patch-based representation of space and a grid-based analogue. The models are tested with respect to their data requirement and recommendations for a better data sampling are derived.}, author = {Hilker, Frank M. and Hinsch, Martin and Poethke, Hans Joachim}, journal = {Ecological Modelling}, keywords = {metapopulation,}, month = 12, number = 4, pages = {476–485}, series = {Pattern and {Processes} of {Dynamic} {Mosaic} {Landscapes} – {Modelling}, {Simulation}, and {Implications}}, title = {Parameterizing, evaluating and comparing metapopulation models with data from individual-based simulations}, volume = 199, year = 2006 }

  %0 Journal Article %1 hilker_parameterizing_2006 %A Hilker, Frank M. %A Hinsch, Martin %A Poethke, Hans Joachim %B Pattern and Processes of Dynamic Mosaic Landscapes -- Modelling, Simulation, and Implications %D 2006 %J Ecological Modelling %N 4 %P 476--485 %R 10.1016/j.ecolmodel.2005.06.011 %T Parameterizing, evaluating and comparing metapopulation models with data from individual-based simulations %U http://www.sciencedirect.com/science/article/pii/S0304380006002912 %V 199 %X Due to the lack of sufficient data and appropriate ecological information parameterizing predictive population dynamical models usually is a difficult task. The approach proposed in this study is meant to overcome this problem by using detailed individual-based simulations to generate artificial data. With short-term data samples, the models to be investigated can be parameterized and their predictions be compared. The flexibility of individual-based simulations as experimental tools also facilitates the evaluation and comparison of different (aggregated) model types. The presented approach is a step towards unifying models of different complexity. As an example we applied it to two metapopulation models of insect species in a highly fragmented landscape: the well-known incidence function model with a patch-based representation of space and a grid-based analogue. The models are tested with respect to their data requirement and recommendations for a better data sampling are derived.
• Multitrophic influences on egg distribution in a specialized leaf beetle at multiple spatial scales. Heisswolf, Annette; Poethke, Hans Joachim; Obermaier, Elisabeth. In Basic and Applied Ecology, 7(6), pp. 565–576. 2006.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{heisswolf_multitrophic_2006, abstract = {Summary Egg distribution in herbivorous beetles can be affected by bottom-up (host plant), and by top-down factors (parasitoids and predators), as well as by other habitat parameters. The importance of bottom-up and top-down effects may change with spatial scale. In this study, we investigated the influence of host plant factors and habitat structure on egg distribution in the leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae), a monophagous herbivore on Salvia pratensis L. (Lamiales: Lamiaceae), on four spatial scales: individual host plant, microhabitat, macrohabitat, and landscape. At the individual host plant scale we studied the correlation between egg clutch incidence and plant size and quality. On all other scales we analyzed the relationship between the egg clutch incidence of C. canaliculata and host plant percentage cover, host plant density, and the surrounding vegetation structure. Vegetation structure was examined as herbivores might escape egg parasitism by depositing their eggs on sites with vegetation factors unfavorable for host searching parasitoids. The probability that egg clutches of C. canaliculata were present increased with an increasing size, percentage cover, and density of the host plant on three of the four spatial scales: individual host plant, microhabitat, and macrohabitat. There was no correlation between vegetation structure and egg clutch occurrence or parasitism on any spatial scale. A high percentage of egg clutches (38–56\%) was parasitized by Foersterella reptans Nees (Hymenoptera: Tetracampidae), the only egg parasitoid, but there was no relationship between egg parasitism and the spatial distribution of egg clutches of C. canaliculata on any of the spatial scales investigated. However, we also discuss results from a further study, which revealed top-down effects on the larval stage.}, author = {Heisswolf, Annette and Poethke, Hans Joachim and Obermaier, Elisabeth}, journal = {Basic and Applied Ecology}, keywords = {parasitism,}, month = 11, number = 6, pages = {565–576}, title = {Multitrophic influences on egg distribution in a specialized leaf beetle at multiple spatial scales}, volume = 7, year = 2006 }

  %0 Journal Article %1 heisswolf_multitrophic_2006 %A Heisswolf, Annette %A Poethke, Hans Joachim %A Obermaier, Elisabeth %D 2006 %J Basic and Applied Ecology %N 6 %P 565--576 %R 10.1016/j.baae.2005.12.004 %T Multitrophic influences on egg distribution in a specialized leaf beetle at multiple spatial scales %U http://www.sciencedirect.com/science/article/pii/S1439179106000089 %V 7 %X Summary Egg distribution in herbivorous beetles can be affected by bottom-up (host plant), and by top-down factors (parasitoids and predators), as well as by other habitat parameters. The importance of bottom-up and top-down effects may change with spatial scale. In this study, we investigated the influence of host plant factors and habitat structure on egg distribution in the leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae), a monophagous herbivore on Salvia pratensis L. (Lamiales: Lamiaceae), on four spatial scales: individual host plant, microhabitat, macrohabitat, and landscape. At the individual host plant scale we studied the correlation between egg clutch incidence and plant size and quality. On all other scales we analyzed the relationship between the egg clutch incidence of C. canaliculata and host plant percentage cover, host plant density, and the surrounding vegetation structure. Vegetation structure was examined as herbivores might escape egg parasitism by depositing their eggs on sites with vegetation factors unfavorable for host searching parasitoids. The probability that egg clutches of C. canaliculata were present increased with an increasing size, percentage cover, and density of the host plant on three of the four spatial scales: individual host plant, microhabitat, and macrohabitat. There was no correlation between vegetation structure and egg clutch occurrence or parasitism on any spatial scale. A high percentage of egg clutches (38–56\%) was parasitized by Foersterella reptans Nees (Hymenoptera: Tetracampidae), the only egg parasitoid, but there was no relationship between egg parasitism and the spatial distribution of egg clutches of C. canaliculata on any of the spatial scales investigated. However, we also discuss results from a further study, which revealed top-down effects on the larval stage.
• Habitat suitability models for the conservation of thermophilic grasshoppers and bush crickets—simple or complex?. Hein, Silke; Voss, Julia; Poethke, Hans-Joachim; Boris, Schröder. In Journal of Insect Conservation, 11(3), p. 221. 2006.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{hein_habitat_2006, abstract = {One goal of conservation biology is the assessment of effects of land use change on species distribution. One approach for identifying the factors, which determine habitat suitability for a species are statistical habitat distribution models. These models are quantitative and can be used for predictions in management scenarios. However, they often have one major shortcoming, which is their complexity. This means that they need several, often costly-to-determine parameters for predictions of species occurrence. We first used habitat suitability models to investigate and determine habitat preferences of three different Orthoptera species. Second, we compared the predictive powers of simple habitat suitability models considering only the ‘habitat type’ as predictor with more complex models taking different habitat factors into account. We found that the habitat type is the most reliable and robust factor, which determines the occurrence of the species studied. Thus, analyses of habitat suitability can easily be carried out on the basis of existing vegetation maps for the conservation of the three species under study. Our results can serve as a basis for the estimation of spatio-temporal distribution and survival probabilities of the species studied and might also be valuable for other species living in dry grasslands.}, author = {Hein, Silke and Voss, Julia and Poethke, Hans-Joachim and Boris, Schröder}, journal = {Journal of Insect Conservation}, keywords = {imported}, month = 12, number = 3, pages = 221, title = {Habitat suitability models for the conservation of thermophilic grasshoppers and bush crickets—simple or complex?}, volume = 11, year = 2006 }

  %0 Journal Article %1 hein_habitat_2006 %A Hein, Silke %A Voss, Julia %A Poethke, Hans-Joachim %A Boris, Schröder %D 2006 %J Journal of Insect Conservation %N 3 %P 221 %R 10.1007/s10841-006-9038-5 %T Habitat suitability models for the conservation of thermophilic grasshoppers and bush crickets—simple or complex? %U http://link.springer.com/article/10.1007/s10841-006-9038-5 %V 11 %X One goal of conservation biology is the assessment of effects of land use change on species distribution. One approach for identifying the factors, which determine habitat suitability for a species are statistical habitat distribution models. These models are quantitative and can be used for predictions in management scenarios. However, they often have one major shortcoming, which is their complexity. This means that they need several, often costly-to-determine parameters for predictions of species occurrence. We first used habitat suitability models to investigate and determine habitat preferences of three different Orthoptera species. Second, we compared the predictive powers of simple habitat suitability models considering only the ‘habitat type’ as predictor with more complex models taking different habitat factors into account. We found that the habitat type is the most reliable and robust factor, which determines the occurrence of the species studied. Thus, analyses of habitat suitability can easily be carried out on the basis of existing vegetation maps for the conservation of the three species under study. Our results can serve as a basis for the estimation of spatio-temporal distribution and survival probabilities of the species studied and might also be valuable for other species living in dry grasslands.
• The control of emigration and its consequences for the survival of populations. Hovestadt, T.; Poethke, H. J. In Ecological Modelling, 190(3-4), pp. 443–453. 2006.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_control_2006, abstract = {Dispersal is the key process enhancing the long-term persistence of metapopulations in heterogeneous and dynamic landscapes. However, any individual emigrating from a occupied patch also increases the risk of local population extinction. The consequences of this increase for metapopulation persistence likely depend on the control of emigration. In this paper, we present results of individual-based simulations to compare the consequences of density-independent (DIE) and density-dependent (DDE) emigration on the extinction risk of local populations and a two-patch metapopulation. (1) For completely isolated patches extinction risk increases linearly with realised emigration rates in the DEE scenario. (2) For the DDE scenario extinction risk is nearly insensitive to emigration as longs as emigration probabilities remain below approximate to 0.2. Survival chances are up to half an order of magnitude larger than for populations with DIE. (3) For low dispersal mortality both modes of emigration increase survival of a metapopulation by ca. one order of magnitude. (4) For high dispersal mortality only DDE can improve the global survival chances of the metapopulation. (5) With DDE individuals are only removed from a population at high population density and the risk of extinction due to demographic stochasticity is thus much smaller compared to the DIE scenario. With density-dependent emigration prospects of metapopulations survival may thus be much higher compared to a system with density-independent emigration. Consequently, the knowledge about the factors driving emigration may significantly affect our conclusions concerning the conservation status of species. (c) 2005 Elsevier B.V. All rights reserved.}, author = {Hovestadt, T. and Poethke, H. J.}, journal = {Ecological Modelling}, keywords = {imported}, month = {01}, note = {WOS:000233859600013}, number = {3-4}, pages = {443–453}, title = {The control of emigration and its consequences for the survival of populations}, volume = 190, year = 2006 }

  %0 Journal Article %1 hovestadt_control_2006 %A Hovestadt, T. %A Poethke, H. J. %D 2006 %J Ecological Modelling %N 3-4 %P 443--453 %R 10.1016/j.ecolmodel.2005.03.023 %T The control of emigration and its consequences for the survival of populations %V 190 %X Dispersal is the key process enhancing the long-term persistence of metapopulations in heterogeneous and dynamic landscapes. However, any individual emigrating from a occupied patch also increases the risk of local population extinction. The consequences of this increase for metapopulation persistence likely depend on the control of emigration. In this paper, we present results of individual-based simulations to compare the consequences of density-independent (DIE) and density-dependent (DDE) emigration on the extinction risk of local populations and a two-patch metapopulation. (1) For completely isolated patches extinction risk increases linearly with realised emigration rates in the DEE scenario. (2) For the DDE scenario extinction risk is nearly insensitive to emigration as longs as emigration probabilities remain below approximate to 0.2. Survival chances are up to half an order of magnitude larger than for populations with DIE. (3) For low dispersal mortality both modes of emigration increase survival of a metapopulation by ca. one order of magnitude. (4) For high dispersal mortality only DDE can improve the global survival chances of the metapopulation. (5) With DDE individuals are only removed from a population at high population density and the risk of extinction due to demographic stochasticity is thus much smaller compared to the DIE scenario. With density-dependent emigration prospects of metapopulations survival may thus be much higher compared to a system with density-independent emigration. Consequently, the knowledge about the factors driving emigration may significantly affect our conclusions concerning the conservation status of species. (c) 2005 Elsevier B.V. All rights reserved.

• Selection of large host plants for oviposition by a monophagous leaf beetle: nutritional quality or enemy-free space?. Heisswolf, Annette; Obermaier, Elisabeth; Poethke, Hans Joachim. In Ecological Entomology, 30(3), pp. 299–306. 2005.
  • [ BibTeX ]
  • [ EndNote ]
  • [ URL ]
  @article{heisswolf_selection_2005, abstract = {Abstract.  1. Oviposition site selection is crucial for the reproductive success of herbivorous insects. According to the preference–performance hypothesis, females should oviposit on host plants that enhance the performance of their offspring. More specifically, the plant vigour hypothesis predicts that females should prefer large and vigorously growing host plants for oviposition and that larvae should perform best on these plants. 2. The present study examined whether females of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) prefer to oviposit on large host plant individuals of the meadow clary and whether large host plants are of higher nutritional quality than small host plants. Subsequently, it was tested whether the female preference correlates with offspring performance and survival. 3. In the field, females preferred large host plant individuals for oviposition and host plant quality, i.e. leaf nitrogen content, was significantly higher in leaves of large than of small host plants. 4. In the laboratory, larval development time was shorter on leaves of large host plant individuals than on small host plant individuals, but this could not be shown in the field. 5. However, a predator-exclusion experiment in the field resulted in a higher survival of larvae on large host plants than on small host plants when all predators had free access to the plants. On caged host plants there was no difference in survival of larvae between plant size categories. 6. It is concluded that females of C. canaliculata select oviposition sites that enhance both performance and survival of their offspring, which meets the predictions of the plant vigour hypothesis.}, author = {Heisswolf, Annette and Obermaier, Elisabeth and Poethke, Hans Joachim}, journal = {Ecological Entomology}, keywords = {content,}, month = {06}, number = 3, pages = {299–306}, title = {Selection of large host plants for oviposition by a monophagous leaf beetle: nutritional quality or enemy-free space?}, volume = 30, year = 2005 }

  %0 Journal Article %1 heisswolf_selection_2005 %A Heisswolf, Annette %A Obermaier, Elisabeth %A Poethke, Hans Joachim %D 2005 %J Ecological Entomology %N 3 %P 299--306 %R 10.1111/j.0307-6946.2005.00706.x %T Selection of large host plants for oviposition by a monophagous leaf beetle: nutritional quality or enemy-free space? %U http://onlinelibrary.wiley.com/doi/10.1111/j.0307-6946.2005.00706.x/abstract %V 30 %X Abstract.  1. Oviposition site selection is crucial for the reproductive success of herbivorous insects. According to the preference–performance hypothesis, females should oviposit on host plants that enhance the performance of their offspring. More specifically, the plant vigour hypothesis predicts that females should prefer large and vigorously growing host plants for oviposition and that larvae should perform best on these plants. 2. The present study examined whether females of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) prefer to oviposit on large host plant individuals of the meadow clary and whether large host plants are of higher nutritional quality than small host plants. Subsequently, it was tested whether the female preference correlates with offspring performance and survival. 3. In the field, females preferred large host plant individuals for oviposition and host plant quality, i.e. leaf nitrogen content, was significantly higher in leaves of large than of small host plants. 4. In the laboratory, larval development time was shorter on leaves of large host plant individuals than on small host plant individuals, but this could not be shown in the field. 5. However, a predator-exclusion experiment in the field resulted in a higher survival of larvae on large host plants than on small host plants when all predators had free access to the plants. On caged host plants there was no difference in survival of larvae between plant size categories. 6. It is concluded that females of C. canaliculata select oviposition sites that enhance both performance and survival of their offspring, which meets the predictions of the plant vigour hypothesis.
• Computer-generated null models as an approach to detect perceptual range in mark-re-sight studies - an example with grasshoppers. Hein, S.; Poethke, H. J.; Hovestadt, T. In Ecological Entomology, 30(2), pp. 225–233. 2005.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hein_computer-generated_2005, abstract = {1. Dispersal and habitat detection are key factors for the colonisation of habitat fragments in heterogeneous landscapes. The ability to recognise a habitat from a certain distance should increase the survival chances of a dispersing individual; however, due to methodological problems there is little information on the perceptual range of most species. 2. In a field experiment, 44 individually marked grasshoppers of the species Oedipoda caerulescens (Orthoptera: Acrididae: Locustinae) were released into an unfamiliar, hostile environment at various distances from a patch of preferred habitat. 3. Whether individuals reached the habitat or not was measured, as well as the daily movement distances. The number of individuals that reached the habitat was tested against computer-generated predictions based on different underlying rules for the movement behaviour of individuals but not accounting for the ability to detect habitat from distance. 4. On the first day a significantly higher proportion of grasshoppers arrived in the habitat than predicted by any of the null models. 5. It was concluded that individuals of O. caerulescens are able to detect their preferred habitat from a distance. 6. Edge permeability was very low as none of the individuals left the habitat once they had reached it. 7. Additional analyses showed that individuals changed movement behaviour from a directed walk with great daily distances in unsuitable habitat to a walk with significantly shorter daily distances within the preferred habitat. 8. The problems that arose in the field experiment are discussed and recommendations are given for further studies.}, author = {Hein, S. and Poethke, H. J. and Hovestadt, T.}, journal = {Ecological Entomology}, keywords = {imported}, month = {04}, note = {WOS:000228204900013}, number = 2, pages = {225–233}, title = {Computer-generated null models as an approach to detect perceptual range in mark-re-sight studies - an example with grasshoppers}, volume = 30, year = 2005 }

  %0 Journal Article %1 hein_computer-generated_2005 %A Hein, S. %A Poethke, H. J. %A Hovestadt, T. %D 2005 %J Ecological Entomology %N 2 %P 225--233 %R 10.1111/j.0307-6946.2005.00680.x %T Computer-generated null models as an approach to detect perceptual range in mark-re-sight studies - an example with grasshoppers %V 30 %X 1. Dispersal and habitat detection are key factors for the colonisation of habitat fragments in heterogeneous landscapes. The ability to recognise a habitat from a certain distance should increase the survival chances of a dispersing individual; however, due to methodological problems there is little information on the perceptual range of most species. 2. In a field experiment, 44 individually marked grasshoppers of the species Oedipoda caerulescens (Orthoptera: Acrididae: Locustinae) were released into an unfamiliar, hostile environment at various distances from a patch of preferred habitat. 3. Whether individuals reached the habitat or not was measured, as well as the daily movement distances. The number of individuals that reached the habitat was tested against computer-generated predictions based on different underlying rules for the movement behaviour of individuals but not accounting for the ability to detect habitat from distance. 4. On the first day a significantly higher proportion of grasshoppers arrived in the habitat than predicted by any of the null models. 5. It was concluded that individuals of O. caerulescens are able to detect their preferred habitat from a distance. 6. Edge permeability was very low as none of the individuals left the habitat once they had reached it. 7. Additional analyses showed that individuals changed movement behaviour from a directed walk with great daily distances in unsuitable habitat to a walk with significantly shorter daily distances within the preferred habitat. 8. The problems that arose in the field experiment are discussed and recommendations are given for further studies.
• Spatial patterns in species-area relationships and species distribution in a West African forest-savanna mosaic. Hovestadt, T.; Poethke, H. J.; Linsenmair, K. E. In Journal of Biogeography, 32(4), pp. 677–684. 2005.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_spatial_2005, abstract = {Aim To investigate the relationship between the slope z of the species-area relationship (SAR) and the intensity of spatial patterns in species number and dissimilarity for woody plants with different modes of seed dispersal. According to island theory we expect, for any given archipelago, steeper slopes and more pronounced spatial patterns for groups of less dispersive species. Location Ivory Coast, West Africa. Methods In a West African forest-savanna mosaic we collected presence-absence data for woody plant species in 49 forest islands. The parameters of the SARs were fitted by nonlinear regressions and then compared for plant species aggregated according to their mode of seed dispersal. We used the Mantel test to calculate the intensity of spatial patterns in species number, i.e. residual deviation from SAR, and species dissimilarity. Results The z-value for bird-dispersed species was lower (0.11) than that for wind-dispersed species (0.27), with mammal-dispersed species taking an intermediate value (0.16). This result suggests that, as a group, bird-dispersed species are better colonizers. The spatial pattern in species number as well as species similarity was more pronounced for bird- compared with wind-dispersed species. Main conclusions The standard interpretation of the theory of island biogeography claims that shallow slopes in the SAR imply low isolation of islands, i.e. good dispersal abilities of species. The results of our study appear to contradict this statement. The contradiction can eventually be resolved by a more detailed account of the colonization process, i.e. by distinguishing between dispersal and consecutive establishment of populations.}, author = {Hovestadt, T. and Poethke, H. J. and Linsenmair, K. E.}, journal = {Journal of Biogeography}, keywords = {imported}, month = {04}, note = {WOS:000228017800010}, number = 4, pages = {677–684}, title = {Spatial patterns in species-area relationships and species distribution in a {West} {African} forest-savanna mosaic}, volume = 32, year = 2005 }

  %0 Journal Article %1 hovestadt_spatial_2005 %A Hovestadt, T. %A Poethke, H. J. %A Linsenmair, K. E. %D 2005 %J Journal of Biogeography %N 4 %P 677--684 %R 10.1111/j.1365-2699.2004.01192.x %T Spatial patterns in species-area relationships and species distribution in a West African forest-savanna mosaic %V 32 %X Aim To investigate the relationship between the slope z of the species-area relationship (SAR) and the intensity of spatial patterns in species number and dissimilarity for woody plants with different modes of seed dispersal. According to island theory we expect, for any given archipelago, steeper slopes and more pronounced spatial patterns for groups of less dispersive species. Location Ivory Coast, West Africa. Methods In a West African forest-savanna mosaic we collected presence-absence data for woody plant species in 49 forest islands. The parameters of the SARs were fitted by nonlinear regressions and then compared for plant species aggregated according to their mode of seed dispersal. We used the Mantel test to calculate the intensity of spatial patterns in species number, i.e. residual deviation from SAR, and species dissimilarity. Results The z-value for bird-dispersed species was lower (0.11) than that for wind-dispersed species (0.27), with mammal-dispersed species taking an intermediate value (0.16). This result suggests that, as a group, bird-dispersed species are better colonizers. The spatial pattern in species number as well as species similarity was more pronounced for bird- compared with wind-dispersed species. Main conclusions The standard interpretation of the theory of island biogeography claims that shallow slopes in the SAR imply low isolation of islands, i.e. good dispersal abilities of species. The results of our study appear to contradict this statement. The contradiction can eventually be resolved by a more detailed account of the colonization process, i.e. by distinguishing between dispersal and consecutive establishment of populations.
• Dispersal and establishment: spatial patterns and species-area relationships. Hovestadt, T.; Poethke, H. J. In Diversity and Distributions, 11(4), pp. 333–340. 2005.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_dispersal_2005, abstract = {According to the equilibrium theory of island biogeography, high colonization ability of species is associated with low exponents (z) of the species-area relationship (SAR) and weak spatial patterns in species number and dissimilarity. However, the relationship between z and the strength of these spatial patterns has not been investigated systematically. We used a multispecies metapopulation model to investigate these relationships in an archipelago of islands. We conclude that this relationship can only be predicted if either the dispersal ability or the power of establishment of species is known. With species richness limited by establishment, we generated high z-values associated with weak spatial patterns in species number and dissimilarity. If species richness was constrained by the dispersal ability of species, we observed low to medium z-values but strong spatial patterns. If the dispersal ability and the abilities of species to establish were both high, z-values and spatial pattern tend to be low and species numbers were limited by the size of the regional species pool.}, author = {Hovestadt, T. and Poethke, H. J.}, journal = {Diversity and Distributions}, keywords = {imported}, month = {07}, note = {WOS:000230784400007}, number = 4, pages = {333–340}, title = {Dispersal and establishment: spatial patterns and species-area relationships}, volume = 11, year = 2005 }

  %0 Journal Article %1 hovestadt_dispersal_2005 %A Hovestadt, T. %A Poethke, H. J. %D 2005 %J Diversity and Distributions %N 4 %P 333--340 %R 10.1111/j.1366-9516.2005.00161.x %T Dispersal and establishment: spatial patterns and species-area relationships %V 11 %X According to the equilibrium theory of island biogeography, high colonization ability of species is associated with low exponents (z) of the species-area relationship (SAR) and weak spatial patterns in species number and dissimilarity. However, the relationship between z and the strength of these spatial patterns has not been investigated systematically. We used a multispecies metapopulation model to investigate these relationships in an archipelago of islands. We conclude that this relationship can only be predicted if either the dispersal ability or the power of establishment of species is known. With species richness limited by establishment, we generated high z-values associated with weak spatial patterns in species number and dissimilarity. If species richness was constrained by the dispersal ability of species, we observed low to medium z-values but strong spatial patterns. If the dispersal ability and the abilities of species to establish were both high, z-values and spatial pattern tend to be low and species numbers were limited by the size of the regional species pool.

• Patch density, movement pattern, and realised dispersal distances in a patch-matrix landscape - a simulation study. Hein, S.; Pfenning, B.; Hovestadt, T.; Poethke, H. J. In Ecological Modelling, 174(4), pp. 411–420. 2004.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hein_patch_2004, abstract = {In metapopulation models it is common practice to use species-specific dispersal distances to predict the exchange of individuals between habitat patches. The influence of patch distribution on the reachability of a habitat patch is usually ignored. In a patch-matrix simulation. we investigated the effect of patch number, movement pattern and dispersal mortality on realised animal dispersal distances. In our spatially-explicit, individual-based simulations we demonstrate that: (1) with increasing number of patches the number of immigrants into patches further away from the release point decreases in all scenarios ("shadow effect"), (2) this effect is strongest for a random movement, (3) for rather uncorrelated walks a proper adjustment of mean dispersal distance in the negative exponential model can account for the effect of patch density on realised dispersal distances, (4) with a more directed walk this is not possible as the distribution of moving animals in the matrix becomes highly heterogeneous. This is due to the narrow but far reaching shadow patches exert on other patches further away from the release point. (C) 2003 Elsevier B.V. All rights reserved.}, author = {Hein, S. and Pfenning, B. and Hovestadt, T. and Poethke, H. J.}, journal = {Ecological Modelling}, keywords = {imported}, month = {06}, note = {WOS:000221284100007}, number = 4, pages = {411–420}, title = {Patch density, movement pattern, and realised dispersal distances in a patch-matrix landscape - a simulation study}, volume = 174, year = 2004 }

  %0 Journal Article %1 hein_patch_2004 %A Hein, S. %A Pfenning, B. %A Hovestadt, T. %A Poethke, H. J. %D 2004 %J Ecological Modelling %N 4 %P 411--420 %R 10.1016/j.ecolmodel.2003.10.005 %T Patch density, movement pattern, and realised dispersal distances in a patch-matrix landscape - a simulation study %V 174 %X In metapopulation models it is common practice to use species-specific dispersal distances to predict the exchange of individuals between habitat patches. The influence of patch distribution on the reachability of a habitat patch is usually ignored. In a patch-matrix simulation. we investigated the effect of patch number, movement pattern and dispersal mortality on realised animal dispersal distances. In our spatially-explicit, individual-based simulations we demonstrate that: (1) with increasing number of patches the number of immigrants into patches further away from the release point decreases in all scenarios ("shadow effect"), (2) this effect is strongest for a random movement, (3) for rather uncorrelated walks a proper adjustment of mean dispersal distance in the negative exponential model can account for the effect of patch density on realised dispersal distances, (4) with a more directed walk this is not possible as the distribution of moving animals in the matrix becomes highly heterogeneous. This is due to the narrow but far reaching shadow patches exert on other patches further away from the release point. (C) 2003 Elsevier B.V. All rights reserved.

• Forecasting plant migration rates: managing uncertainty for risk assessment. Higgins, S. I.; Clark, J. S.; Nathan, R.; Hovestadt, T.; Schurr, F.; Fragoso, J. M. V.; Aguiar, M. R.; Ribbens, E.; Lavorel, S. In Journal of Ecology, 91(3), pp. 341–347. 2003.
  • [ BibTeX ]
  • [ EndNote ]
  @article{higgins_forecasting_2003, abstract = {1 Anthropogenic changes in the global climate are shifting the potential ranges of many plant species. 2 Changing climates will allow some species the opportunity to expand their range, others may experience a contraction in their potential range, while the current and future ranges of some species may not overlap. Our capacity to generalize about the threat these range shifts pose to plant diversity is limited by many sources of uncertainty. 3 In this paper we summarize sources of uncertainty for migration forecasts and suggest a research protocol for making forecasts in the context of uncertainty.}, author = {Higgins, S. I. and Clark, J. S. and Nathan, R. and Hovestadt, T. and Schurr, F. and Fragoso, J. M. V. and Aguiar, M. R. and Ribbens, E. and Lavorel, S.}, journal = {Journal of Ecology}, keywords = {imported}, month = {06}, note = {WOS:000183144700001}, number = 3, pages = {341–347}, title = {Forecasting plant migration rates: managing uncertainty for risk assessment}, volume = 91, year = 2003 }

  %0 Journal Article %1 higgins_forecasting_2003 %A Higgins, S. I. %A Clark, J. S. %A Nathan, R. %A Hovestadt, T. %A Schurr, F. %A Fragoso, J. M. V. %A Aguiar, M. R. %A Ribbens, E. %A Lavorel, S. %D 2003 %J Journal of Ecology %N 3 %P 341--347 %R 10.1046/j.1365-2745.2003.00781.x %T Forecasting plant migration rates: managing uncertainty for risk assessment %V 91 %X 1 Anthropogenic changes in the global climate are shifting the potential ranges of many plant species. 2 Changing climates will allow some species the opportunity to expand their range, others may experience a contraction in their potential range, while the current and future ranges of some species may not overlap. Our capacity to generalize about the threat these range shifts pose to plant diversity is limited by many sources of uncertainty. 3 In this paper we summarize sources of uncertainty for migration forecasts and suggest a research protocol for making forecasts in the context of uncertainty.
• Movement patterns of the bush cricket Platycleis albopunctata in different types of habitat: matrix is not always matrix. Hein, S.; Gombert, J.; Hovestadt, T.; Poethke, H. J. In Ecological Entomology, 28(4), pp. 432–438. 2003.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hein_movement_2003, abstract = {1. Inter-patch movement is usually assumed to be homogeneous across a landscape. As the intervening area between suitable patches is usually richly textured, it cannot be assumed to be uniform in real landscapes. 2. In an experimental mark-and-resight study, the movement behaviour of the bush cricket Platycleis albopunctata in four habitat types as well as at the border between two of these habitat types was observed. 3. Analysis of recapture data indicated differences in mortality risk (or emigration rates) between habitat types. 4. When released at the border between suitable habitat and a crop field, P. albopunctata did not show a consistent preference for the suitable habitat. This suggests that the crop field is at least temporarily attractive for P. albopunctata . 5. Movement in suitable habitat was not always different from movement in the matrix, and movement between different types of matrix also differed. 6. The results indicate that the movement behaviour of P. albopunctata is influenced not only by suitability for breeding but also by structural resistance and other factors (e.g. food availability or habitat-specific mortality risk).}, author = {Hein, S. and Gombert, J. and Hovestadt, T. and Poethke, H. J.}, journal = {Ecological Entomology}, keywords = {imported}, month = {08}, note = {WOS:000184460700006}, number = 4, pages = {432–438}, title = {Movement patterns of the bush cricket {Platycleis} albopunctata in different types of habitat: matrix is not always matrix}, volume = 28, year = 2003 }

  %0 Journal Article %1 hein_movement_2003 %A Hein, S. %A Gombert, J. %A Hovestadt, T. %A Poethke, H. J. %D 2003 %J Ecological Entomology %N 4 %P 432--438 %R 10.1046/j.1365-2311.2003.00531.x %T Movement patterns of the bush cricket Platycleis albopunctata in different types of habitat: matrix is not always matrix %V 28 %X 1. Inter-patch movement is usually assumed to be homogeneous across a landscape. As the intervening area between suitable patches is usually richly textured, it cannot be assumed to be uniform in real landscapes. 2. In an experimental mark-and-resight study, the movement behaviour of the bush cricket Platycleis albopunctata in four habitat types as well as at the border between two of these habitat types was observed. 3. Analysis of recapture data indicated differences in mortality risk (or emigration rates) between habitat types. 4. When released at the border between suitable habitat and a crop field, P. albopunctata did not show a consistent preference for the suitable habitat. This suggests that the crop field is at least temporarily attractive for P. albopunctata . 5. Movement in suitable habitat was not always different from movement in the matrix, and movement between different types of matrix also differed. 6. The results indicate that the movement behaviour of P. albopunctata is influenced not only by suitability for breeding but also by structural resistance and other factors (e.g. food availability or habitat-specific mortality risk).

• Evolution of reduced dispersal mortality and ’fat-tailed’ dispersal kernels in autocorrelated landscapes. Hovestadt, T.; Messner, S.; Poethke, H. J. In Proceedings of the Royal Society B-Biological Sciences, 268(1465), pp. 385–391. 2001.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_evolution_2001, abstract = {Models describing the evolution of dispersal strategies have mostly focused on the evolution of dispersal rates. Taking trees as a model for organisms with undirected, passive dispersal, we have developed an individual-based, spatially explicit simulation tool to investigate the evolution of the dispersal kernel, P(r), and its resulting cumulative seed-density distribution, D(r). Simulations were run on a variety of fractal landscapes differing in the fraction of suitable habitat and the spatial autocorrelation. Starting from a uniform D(r), evolution led to an increase in the fraction of seeds staying in the home cell, a reduction of the dispel sal mortality (arrival in unsuitable habitat), and the evolution of 'fat-tailed' D(r) in autocorrelated landscapes and approximately uniform D(r) in random landscapes. The evolutionary process was characterized by long periods of stasis with a few bouts of rapid change in the dispersal rate.}, author = {Hovestadt, T. and Messner, S. and Poethke, H. J.}, journal = {Proceedings of the Royal Society B-Biological Sciences}, keywords = {imported}, month = {02}, note = {WOS:000167214000008}, number = 1465, pages = {385–391}, title = {Evolution of reduced dispersal mortality and 'fat-tailed' dispersal kernels in autocorrelated landscapes}, volume = 268, year = 2001 }

  %0 Journal Article %1 hovestadt_evolution_2001 %A Hovestadt, T. %A Messner, S. %A Poethke, H. J. %D 2001 %J Proceedings of the Royal Society B-Biological Sciences %N 1465 %P 385--391 %T Evolution of reduced dispersal mortality and 'fat-tailed' dispersal kernels in autocorrelated landscapes %V 268 %X Models describing the evolution of dispersal strategies have mostly focused on the evolution of dispersal rates. Taking trees as a model for organisms with undirected, passive dispersal, we have developed an individual-based, spatially explicit simulation tool to investigate the evolution of the dispersal kernel, P(r), and its resulting cumulative seed-density distribution, D(r). Simulations were run on a variety of fractal landscapes differing in the fraction of suitable habitat and the spatial autocorrelation. Starting from a uniform D(r), evolution led to an increase in the fraction of seeds staying in the home cell, a reduction of the dispel sal mortality (arrival in unsuitable habitat), and the evolution of 'fat-tailed' D(r) in autocorrelated landscapes and approximately uniform D(r) in random landscapes. The evolutionary process was characterized by long periods of stasis with a few bouts of rapid change in the dispersal rate.

• Variability in dispersal distances generates typical successional patterns: a simple simulation model. Hovestadt, T.; Poethke, H. J.; Messner, S. In Oikos, 90(3), pp. 612–619. 2000.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_variability_2000, author = {Hovestadt, T. and Poethke, H. J. and Messner, S.}, journal = {Oikos}, keywords = {imported}, month = {09}, note = {WOS:000089830000020}, number = 3, pages = {612–619}, title = {Variability in dispersal distances generates typical successional patterns: a simple simulation model}, volume = 90, year = 2000 }

  %0 Journal Article %1 hovestadt_variability_2000 %A Hovestadt, T. %A Poethke, H. J. %A Messner, S. %D 2000 %J Oikos %N 3 %P 612--619 %R 10.1034/j.1600-0706.2000.900320.x %T Variability in dispersal distances generates typical successional patterns: a simple simulation model %V 90

• Seed dispersal mechanisms and the vegetation of forest islands in a West African forest-savanna mosaic (Comoe National Park, Ivory {Coast}). Hovestadt, T.; Yao, P.; Linsenmair, K. E. In Plant Ecology, 144(1), pp. 1–25. 1999.
  • [ BibTeX ]
  • [ EndNote ]
  @article{hovestadt_seed_1999, abstract = {The transition zone between forest and savanna is typically characterized by a dynamic patchwork of forest and savanna. We studied the woody plant species composition of 49 forest islands, 18 savanna, and 3 gallery forest plots in the Comoe National Park (Ivory Coast), West Africa's largest savanna reserve. TWINSPAN makes a clear distinction in vegetational composition between these three major habitat types but, nevertheless, more than 50\% of the 292 species occur in at least 2 of them. The gallery forest is dominated by Cynometra megalophylla (Caesalpiniaceae), a genus known to dominate humid forests in other afrotropical regions. Ordination reveals four distinct categories of forest islands, (1) humid forests comparable to the gallery forest in their species composition, (2) dry disturbed and (3) dry undisturbed forests and (4) forests formerly inhabited by humans. Disturbed forests harbor more savanna species but also a distinct group of disturbance-tolerant forest species. Compared to other forest species, in this latter group we found an exceptionally high fraction of animal dispersed species (80\% vs. 58\%), while wind dispersed species or species lacking long distance seed dispersal mechanisms were correspondingly rare. This pattern occurs in spite of the fact that the frequency of wind dispersed species in general increases from dense humid forests to open dry forests and savanna. Species lacking long distance dispersal mechanisms are most abundant among those specialized on humid forests. These observations suggest that the species composition of forest islands is to some extent determined by the seed dispersal abilities of the different species.}, author = {Hovestadt, T. and Yao, P. and Linsenmair, K. E.}, journal = {Plant Ecology}, keywords = {imported}, month = {09}, note = {WOS:000082532400001}, number = 1, pages = {1–25}, title = {Seed dispersal mechanisms and the vegetation of forest islands in a {West} {African} forest-savanna mosaic ({Comoe} {National} {Park}, {Ivory} {Coast})}, volume = 144, year = 1999 }

  %0 Journal Article %1 hovestadt_seed_1999 %A Hovestadt, T. %A Yao, P. %A Linsenmair, K. E. %D 1999 %J Plant Ecology %N 1 %P 1--25 %R 10.1023/A:1009764031116 %T Seed dispersal mechanisms and the vegetation of forest islands in a West African forest-savanna mosaic (Comoe National Park, Ivory {Coast}) %V 144 %X The transition zone between forest and savanna is typically characterized by a dynamic patchwork of forest and savanna. We studied the woody plant species composition of 49 forest islands, 18 savanna, and 3 gallery forest plots in the Comoe National Park (Ivory Coast), West Africa's largest savanna reserve. TWINSPAN makes a clear distinction in vegetational composition between these three major habitat types but, nevertheless, more than 50% of the 292 species occur in at least 2 of them. The gallery forest is dominated by Cynometra megalophylla (Caesalpiniaceae), a genus known to dominate humid forests in other afrotropical regions. Ordination reveals four distinct categories of forest islands, (1) humid forests comparable to the gallery forest in their species composition, (2) dry disturbed and (3) dry undisturbed forests and (4) forests formerly inhabited by humans. Disturbed forests harbor more savanna species but also a distinct group of disturbance-tolerant forest species. Compared to other forest species, in this latter group we found an exceptionally high fraction of animal dispersed species (80\% vs. 58\%), while wind dispersed species or species lacking long distance seed dispersal mechanisms were correspondingly rare. This pattern occurs in spite of the fact that the frequency of wind dispersed species in general increases from dense humid forests to open dry forests and savanna. Species lacking long distance dispersal mechanisms are most abundant among those specialized on humid forests. These observations suggest that the species composition of forest islands is to some extent determined by the seed dispersal abilities of the different species.