Matthew Wund - Academia.edu (original) (raw)
Papers by Matthew Wund
If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity sp... more If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity specific to that group should consistently give rise to similar phenotypes. Parallel selection on those similar phenotypes could lead to the repeated evolution of characteristic ecotypes, a property common to many adaptive radiations. A key prediction of this "flexible stem" model of adaptive radiation is that patterns of phenotypic divergence in derived groups should mirror patterns of developmental plasticity in their common ancestor. The threespine stickleback radiation provides an excellent opportunity to test this prediction because the marine form is representative of the ancestral stem group, which has repeatedly given rise to several characteristic ecotypes. We examined plasticity of several aspects of shape and trophic morphology in response to diets characteristic of either the derived benthic or limnetic ecotypes. When marine fish were reared on alternative diets, plasticity of head and mouth shape paralleled phenotypic divergence between the derived ecotypes, supporting the flexible stem model. Benthic and limnetic fish exhibited patterns of plasticity similar to the marine population; however, some differences in population means were present, as well as subtle differences in shape plasticity in the benthic population, indicating a role for genetic accommodation in this system
Behavioral Ecology, 2022
Invasive predators often impose devastating selection pressures on native prey species. However, ... more Invasive predators often impose devastating selection pressures on native prey species. However, their effects can be regionally dependent and influenced by the local ecological conditions of their invaded habitats. Evolved behavioral phenotypes are important mechanisms by which prey adapt to the presence of novel predators. Here, we asked how behavior and behavioral plasticity of threespine stickleback (Gasterosteus aculeatus) populations have evolved following the introduction of the invasive predator, northern pike (Esox lucius). We examined the behavior of F1 offspring generated from three pike-free and three pike-invaded populations and measured how stickleback activity and plant use behaviors, and their plasticity, have evolved following pike introduction. To evaluate plasticity, we exposed juvenile stickleback to predator cues during their first year of development and then evaluated how this repeated exposure influenced behavioral responses to an artificial predation event. ...
Evolutionary Ecology Research, 2016
Background: In 2009, anadromous threespine stickleback (Gasterosteus aculeatus) were stocked in C... more Background: In 2009, anadromous threespine stickleback (Gasterosteus aculeatus) were stocked in Cheney Lake, Alaska, following treatment with the ichthyocide rotenone to remove invasive northern pike (Esox lucius), but which also extirpated native species. This introduction provides an opportunity to directly observe the evolutionary transition of oceanic stickleback to a freshwater-adapted population. Objective: Rear offspring of F1 Cheney Lake stickleback under two common garden treatments alongside fish from Rabbit Slough, their anadromous source population, to test for rapid morphological evolution and contributions of phenotypic plasticity to morphological divergence. Methods: We reared 198 Cheney Lake and 209 Rabbit Slough stickleback under two conditions designed to simulate the habitat structure and diets of complex, shallow lake and simple, open-water habitats. We preserved stickleback at four time intervals to account for allometric growth effects. We made linear measureme...
Evolutionary Ecology Research, 2017
Background: Prey often make behavioural and morphological adaptations to avoid predation, and the... more Background: Prey often make behavioural and morphological adaptations to avoid predation, and these alternative defence mechanisms may either compensate for, or reinforce, one another. Objective: We examined correlations between anti-predator behaviour and morphology in threespine stickleback fish (Gasterosteus aculeatus) in four environments distinguished by their predation histories: marine/anadromous populations co-existing with native predatory fish (representative of the ancestral environment), and three freshwater environments with native, introduced, and no predatory fish, respectively. To determine whether morphological and behavioural defences reinforce one another (trait co-specialization) or whether they represent alternative strategies for defence (trait compensation), we related morphology of laboratoryreared stickleback to the intensity of their responses to a simulated predator attack, which had previously been assessed (Wund et al., 2015). Methods: Eight aspects of s...
Evolutionary Ecology Research, 2016
Background: Marine or anadromous threespine stickleback have colonized many northern Holarctic la... more Background: Marine or anadromous threespine stickleback have colonized many northern Holarctic lakes after glacial recession, and their freshwater descendants have diverged in characteristic ways. Such divergence begins within a few generations, but previous studies have sampled only one generation or initiated sampling several generations after the populations were founded. Rotenone treatment of two Cook Inlet lakes to exterminate invasive northern pike also eliminated native threespine stickleback, creating an opportunity to introduce anadromous stickleback and observe their adaptation to freshwater conditions for multiple generations, beginning immediately after we founded the populations. Methods: In 2009 and 2011, we released about 3000 reproductively mature anadromous threespine stickleback into each lake. We sampled the source population and made annual samples from the two introduced populations. These samples have been preserved for future analysis. We estimated annual vari...
Because of complex interactions among genes and the environment, individual organisms can display... more Because of complex interactions among genes and the environment, individual organisms can display remarkable phenotypic variation throughout their lives. Environmental change, ontogeny, and patterns of trait covariation all contribute to within-individual phenotypic variation; taken together, these factors have been conceptualized as the developmental norm of reaction (DRN), a multivariate function describing phenotypic change across environments (i.e., phenotypic plasticity), through ontogeny, and as covarying traits interact. When considering the development and evolution of behavior, I argue that it is useful to consider learning as a fourth component of the DRN framework. Not only does learning contribute to within-individual phenotypic variation, it also can interact in complex ways with the other three axes of the DRN. I investigated the role learning plays in the development of a complex and variable behavior: bat echolocation. In a field study, I demonstrated that individual little brown bats, Myotis lucifugus, regularly hunted in a wide variety of habitats. Nightly, individuals foraged over a lake (open space) and within a moderately dense forest (cluttered space), and they changed the acoustical properties of their echolocation to match the physical properties of each environment. Using behavioral experiments, I found that flexible echolocation develops independent of direct experience with different habitats, and juvenile bats subsequently learn to improve calls as they gain experience hunting in various settings. The importance of learning differed across habitat treatments, indicating an interaction between learning and the environment. To investigate a possible interaction between learning and ontogeny, I studied the learning ability of adults in similar experiments. Adult bats foraged considerably less than juveniles in the experiments, making it difficult to record any echolocation calls at all. While this result may indicate an inability of adults to respond as well as juveniles to novel conditions, I argue that it represents an artifact of adults' reduced motivation to forage following extended captivity. Nevertheless, this work demonstrated that interactions between learning and the other axes of the DRN can lead to complex patterns of phenotypic development.Ph.D.Biological SciencesEcologyZoologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125259/2/3186794.pd
Ecology of Freshwater Fish, 2021
The American Biology Teacher, 2015
Optimal foraging theory attempts to explain the foraging patterns observed in animals, including ... more Optimal foraging theory attempts to explain the foraging patterns observed in animals, including their choice of particular food items and foraging locations. We describe three experiments designed to test hypotheses about food choice and foraging habitat preference using bird feeders. These experiments can be used alone or in combination and can also provide a foundation for students to develop extensions incorporating the basic methodology. We see these experiments as most applicable in secondary and postsecondary education, but they could be adapted for a variety of educational environments and for students with a variety of backgrounds.
Integrative and comparative biology, Jan 10, 2015
At the end of the 19th century, the suggestion was made by several scientists, including J. M. Ba... more At the end of the 19th century, the suggestion was made by several scientists, including J. M. Baldwin, that behavioral responses to environmental change could both rescue populations from extinction (Baldwin Effect) and influence the course of subsequent evolution. Here we provide the historical and theoretical background for this argument and offer evidence of the importance of these ideas for understanding how animals (and other organisms that exhibit behavior) will respond to the rapid environmental changes caused by human activity. We offer examples from long-term research on the evolution of behavioral and other phenotypes in the adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus), a radiation in which it is possible to infer ancestral patterns of behavioral plasticity relative to the post-glacial freshwater radiation in northwestern North America, and to use patterns of parallelism and contemporary evolution to understand adaptive causes of response...
The Quarterly Review of Biology, 2006
The American Naturalist, 2008
If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity sp... more If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity specific to that group should consistently give rise to similar phenotypes. Parallel selection on those similar phenotypes could lead to the repeated evolution of characteristic ecotypes, a property common to many adaptive radiations. A key prediction of this "flexible stem" model of adaptive radiation is that patterns of phenotypic divergence in derived groups should mirror patterns of developmental plasticity in their common ancestor. The threespine stickleback radiation provides an excellent opportunity to test this prediction because the marine form is representative of the ancestral stem group, which has repeatedly given rise to several characteristic ecotypes. We examined plasticity of several aspects of shape and trophic morphology in response to diets characteristic of either the derived benthic ecotype or the limnetic ecotype. When marine fish were reared on alternative diets, plasticity of head and mouth shape paralleled phenotypic divergence between the derived ecotypes, supporting the flexible stem model. Benthic and limnetic fish exhibited patterns of plasticity similar to those of the marine population; however, some differences in population means were present, as well as subtle differences in shape plasticity in the benthic population, indicating a role for genetic accommodation in this system.
Proceedings of the National Academy of Sciences, 2002
It is a mainstay of community ecology that local exclusion of species will result if competitive ... more It is a mainstay of community ecology that local exclusion of species will result if competitive pressures become too large. The pattern of exclusion may be complicated, but the qualitative orthodoxy has changed little since the pioneering work of Lotka, Volterra, and Gause—no two species can occupy the same niche. Stated in a more precise form, the higher the intensity of interspecific competition in an assemblage of species, the fewer the number of species that can coexist in perpetuity. We suggest that this orthodoxy results from “linear” thinking, and that if the classical equations are formulated more realistically with attendant nonlinearities, the orthodoxy breaks down and higher levels of competition may actually increase the likelihood that species will avoid competitive exclusion. Furthermore, this increased probability of coexistence at higher levels of competition is accompanied by characteristic dynamic patterns: ( i ) at lower levels of competition, after all extinctio...
Northeastern Naturalist, 2007
... 1988. Timber Rattlesnakes (Crotalus horridus) of the Pine Barrens: Their movement patterns an... more ... 1988. Timber Rattlesnakes (Crotalus horridus) of the Pine Barrens: Their movement patterns and habitat preference. ... In press Ecology of the Aruba Island Rattlesnake, Crotalus durissus unicolor. ... A field study of the spatial ecology and movements of a threatened snake species ...
Journal of Structural Biology, 2010
In this study, a quantitative investigation of the microstructure and composition of field-caught... more In this study, a quantitative investigation of the microstructure and composition of field-caught marine Gasterosteus aculeatus (threespine stickleback) armor is presented, which provides useful phylogenetic information and insights into biomechanical function. Micro-computed tomography (lCT) was employed to create full three-dimensional images of the dorsal spines and basal plate, lateral plates, pelvic girdle and spines and to assess structural and compositional properties such as the spatial distribution of thickness ($100-300 lm), the heterogeneous cross-sectional geometry (centrally thickened), plate-to-plate juncture and overlap ($50% of the plate width), and bone mineral density (634-748 HA/cm 3). The convolution of plate geometry in conjunction with plate-to-plate overlap allows a relatively constant armor thickness to be maintained throughout the assembly, promoting spatially homogeneous protection and thereby avoiding weakness at the armor unit interconnections. Plate-to-plate junctures act to register and join the plates while permitting compliance in sliding and rotation in selected directions. Mercury porosimetry was used to determine the pore size distribution and volume percent porosity of the lateral plates (20-35 vol.%) and spines (10-15 vol.%). SEM and lCT revealed a porous, sandwich-like cross-section beneficial for bending stiffness and strength at minimum weight. Back-scattered electron microscopy and energy dispersive X-ray analysis were utilized to quantify the weight percent mineral content (58-68%). Scanning electron microscopy and surface profilometry were used to characterize the interior and exterior surface topography (tubercles) of the lateral plates. The results obtained in this study are discussed in the context of mechanical function, performance, fitness, and survivability.
Journal of Medical Entomology, 2009
The importance of predation as a mortality factor in adult mosquitoes has received only limited a... more The importance of predation as a mortality factor in adult mosquitoes has received only limited attention in the scientiÞc literature. Despite the lack of consensus among researchers as to whether bats are important predators of mosquitoes, there have been no attempts to directly document the effect of bats on mosquito populations or behavior. We conducted an enclosure experiment to test the hypothesis that bats reduce the local abundance of ovipositing female mosquitoes by examining whether the northern long-eared bat (Myotis septentrionalis Trouessart) had an effect on Culex spp. (Diptera: Culicidae) oviposition, using naturally occurring mosquitoes, either through direct predation or trait mediated effects on mosquito behavior. We found a signiÞcant, 32% reduction in egg-laying activity associated with bat predation. ArtiÞcial oviposition habitats directly outside bat enclosures experienced no reduction in oviposition; we attributed the observed reduction in egg-laying activity to direct predation on ovipositing females by bats and not changes in mosquito behavior. In addition, we noted a decrease in the number of larval mosquitoes in enclosures exposed to bat predation. These results suggest the impact of aerial predators on pathogen transmission may be large, and warrants further scientiÞc investigation.
Integrative and Comparative Biology, 2012
In the past decade, there has been a resurgent interest in whether and how phenotypic plasticity ... more In the past decade, there has been a resurgent interest in whether and how phenotypic plasticity might impact evolutionary processes. Of fundamental importance is how the environment influences individual phenotypic development while simultaneously selecting among phenotypic variants in a population. Conceptual and theoretical treatments of the evolutionary implications of plasticity are numerous, as are criticisms of the conclusions. As such, the time is ripe for empirical evidence to catch up with theoretical predictions. To this end, I provide a summary of eight hypotheses at the core of this issue, highlighting various approaches by which they can be tested. My goal is to provide practical guidance to those seeking to understand the complex ways by which phenotypic plasticity can influence evolutionary innovation and diversification.
Trends in ecology & evolution, 2010
Phenotypic plasticity (the ability of a single genotype to produce multiple phenotypes in respons... more Phenotypic plasticity (the ability of a single genotype to produce multiple phenotypes in response to variation in the environment) is commonplace. Yet its evolutionary significance remains controversial, especially in regard to whether and how it impacts diversification and speciation. Here, we review recent theory on how plasticity promotes: (i) the origin of novel phenotypes, (ii) divergence among populations and species, (iii) the formation of new species and (iv) adaptive radiation. We also discuss the latest empirical support for each of these evolutionary pathways to diversification and identify potentially profitable areas for future research. Generally, phenotypic plasticity can play a largely underappreciated role in driving diversification and speciation.
Ethology, 2007
... The Effects of Relaxed and Reversed Selection by Predators on the Antipredator Behavior of th... more ... The Effects of Relaxed and Reversed Selection by Predators on the Antipredator Behavior of the Threespine Stickleback, Gasterosteus aculeatus. Alexis Messler,; Matthew A. Wund,; John A. Baker,; Susan A. Foster. ... 1993; Bell & Ortí 1994). ...
If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity sp... more If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity specific to that group should consistently give rise to similar phenotypes. Parallel selection on those similar phenotypes could lead to the repeated evolution of characteristic ecotypes, a property common to many adaptive radiations. A key prediction of this "flexible stem" model of adaptive radiation is that patterns of phenotypic divergence in derived groups should mirror patterns of developmental plasticity in their common ancestor. The threespine stickleback radiation provides an excellent opportunity to test this prediction because the marine form is representative of the ancestral stem group, which has repeatedly given rise to several characteristic ecotypes. We examined plasticity of several aspects of shape and trophic morphology in response to diets characteristic of either the derived benthic or limnetic ecotypes. When marine fish were reared on alternative diets, plasticity of head and mouth shape paralleled phenotypic divergence between the derived ecotypes, supporting the flexible stem model. Benthic and limnetic fish exhibited patterns of plasticity similar to the marine population; however, some differences in population means were present, as well as subtle differences in shape plasticity in the benthic population, indicating a role for genetic accommodation in this system
Behavioral Ecology, 2022
Invasive predators often impose devastating selection pressures on native prey species. However, ... more Invasive predators often impose devastating selection pressures on native prey species. However, their effects can be regionally dependent and influenced by the local ecological conditions of their invaded habitats. Evolved behavioral phenotypes are important mechanisms by which prey adapt to the presence of novel predators. Here, we asked how behavior and behavioral plasticity of threespine stickleback (Gasterosteus aculeatus) populations have evolved following the introduction of the invasive predator, northern pike (Esox lucius). We examined the behavior of F1 offspring generated from three pike-free and three pike-invaded populations and measured how stickleback activity and plant use behaviors, and their plasticity, have evolved following pike introduction. To evaluate plasticity, we exposed juvenile stickleback to predator cues during their first year of development and then evaluated how this repeated exposure influenced behavioral responses to an artificial predation event. ...
Evolutionary Ecology Research, 2016
Background: In 2009, anadromous threespine stickleback (Gasterosteus aculeatus) were stocked in C... more Background: In 2009, anadromous threespine stickleback (Gasterosteus aculeatus) were stocked in Cheney Lake, Alaska, following treatment with the ichthyocide rotenone to remove invasive northern pike (Esox lucius), but which also extirpated native species. This introduction provides an opportunity to directly observe the evolutionary transition of oceanic stickleback to a freshwater-adapted population. Objective: Rear offspring of F1 Cheney Lake stickleback under two common garden treatments alongside fish from Rabbit Slough, their anadromous source population, to test for rapid morphological evolution and contributions of phenotypic plasticity to morphological divergence. Methods: We reared 198 Cheney Lake and 209 Rabbit Slough stickleback under two conditions designed to simulate the habitat structure and diets of complex, shallow lake and simple, open-water habitats. We preserved stickleback at four time intervals to account for allometric growth effects. We made linear measureme...
Evolutionary Ecology Research, 2017
Background: Prey often make behavioural and morphological adaptations to avoid predation, and the... more Background: Prey often make behavioural and morphological adaptations to avoid predation, and these alternative defence mechanisms may either compensate for, or reinforce, one another. Objective: We examined correlations between anti-predator behaviour and morphology in threespine stickleback fish (Gasterosteus aculeatus) in four environments distinguished by their predation histories: marine/anadromous populations co-existing with native predatory fish (representative of the ancestral environment), and three freshwater environments with native, introduced, and no predatory fish, respectively. To determine whether morphological and behavioural defences reinforce one another (trait co-specialization) or whether they represent alternative strategies for defence (trait compensation), we related morphology of laboratoryreared stickleback to the intensity of their responses to a simulated predator attack, which had previously been assessed (Wund et al., 2015). Methods: Eight aspects of s...
Evolutionary Ecology Research, 2016
Background: Marine or anadromous threespine stickleback have colonized many northern Holarctic la... more Background: Marine or anadromous threespine stickleback have colonized many northern Holarctic lakes after glacial recession, and their freshwater descendants have diverged in characteristic ways. Such divergence begins within a few generations, but previous studies have sampled only one generation or initiated sampling several generations after the populations were founded. Rotenone treatment of two Cook Inlet lakes to exterminate invasive northern pike also eliminated native threespine stickleback, creating an opportunity to introduce anadromous stickleback and observe their adaptation to freshwater conditions for multiple generations, beginning immediately after we founded the populations. Methods: In 2009 and 2011, we released about 3000 reproductively mature anadromous threespine stickleback into each lake. We sampled the source population and made annual samples from the two introduced populations. These samples have been preserved for future analysis. We estimated annual vari...
Because of complex interactions among genes and the environment, individual organisms can display... more Because of complex interactions among genes and the environment, individual organisms can display remarkable phenotypic variation throughout their lives. Environmental change, ontogeny, and patterns of trait covariation all contribute to within-individual phenotypic variation; taken together, these factors have been conceptualized as the developmental norm of reaction (DRN), a multivariate function describing phenotypic change across environments (i.e., phenotypic plasticity), through ontogeny, and as covarying traits interact. When considering the development and evolution of behavior, I argue that it is useful to consider learning as a fourth component of the DRN framework. Not only does learning contribute to within-individual phenotypic variation, it also can interact in complex ways with the other three axes of the DRN. I investigated the role learning plays in the development of a complex and variable behavior: bat echolocation. In a field study, I demonstrated that individual little brown bats, Myotis lucifugus, regularly hunted in a wide variety of habitats. Nightly, individuals foraged over a lake (open space) and within a moderately dense forest (cluttered space), and they changed the acoustical properties of their echolocation to match the physical properties of each environment. Using behavioral experiments, I found that flexible echolocation develops independent of direct experience with different habitats, and juvenile bats subsequently learn to improve calls as they gain experience hunting in various settings. The importance of learning differed across habitat treatments, indicating an interaction between learning and the environment. To investigate a possible interaction between learning and ontogeny, I studied the learning ability of adults in similar experiments. Adult bats foraged considerably less than juveniles in the experiments, making it difficult to record any echolocation calls at all. While this result may indicate an inability of adults to respond as well as juveniles to novel conditions, I argue that it represents an artifact of adults' reduced motivation to forage following extended captivity. Nevertheless, this work demonstrated that interactions between learning and the other axes of the DRN can lead to complex patterns of phenotypic development.Ph.D.Biological SciencesEcologyZoologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125259/2/3186794.pd
Ecology of Freshwater Fish, 2021
The American Biology Teacher, 2015
Optimal foraging theory attempts to explain the foraging patterns observed in animals, including ... more Optimal foraging theory attempts to explain the foraging patterns observed in animals, including their choice of particular food items and foraging locations. We describe three experiments designed to test hypotheses about food choice and foraging habitat preference using bird feeders. These experiments can be used alone or in combination and can also provide a foundation for students to develop extensions incorporating the basic methodology. We see these experiments as most applicable in secondary and postsecondary education, but they could be adapted for a variety of educational environments and for students with a variety of backgrounds.
Integrative and comparative biology, Jan 10, 2015
At the end of the 19th century, the suggestion was made by several scientists, including J. M. Ba... more At the end of the 19th century, the suggestion was made by several scientists, including J. M. Baldwin, that behavioral responses to environmental change could both rescue populations from extinction (Baldwin Effect) and influence the course of subsequent evolution. Here we provide the historical and theoretical background for this argument and offer evidence of the importance of these ideas for understanding how animals (and other organisms that exhibit behavior) will respond to the rapid environmental changes caused by human activity. We offer examples from long-term research on the evolution of behavioral and other phenotypes in the adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus), a radiation in which it is possible to infer ancestral patterns of behavioral plasticity relative to the post-glacial freshwater radiation in northwestern North America, and to use patterns of parallelism and contemporary evolution to understand adaptive causes of response...
The Quarterly Review of Biology, 2006
The American Naturalist, 2008
If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity sp... more If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity specific to that group should consistently give rise to similar phenotypes. Parallel selection on those similar phenotypes could lead to the repeated evolution of characteristic ecotypes, a property common to many adaptive radiations. A key prediction of this "flexible stem" model of adaptive radiation is that patterns of phenotypic divergence in derived groups should mirror patterns of developmental plasticity in their common ancestor. The threespine stickleback radiation provides an excellent opportunity to test this prediction because the marine form is representative of the ancestral stem group, which has repeatedly given rise to several characteristic ecotypes. We examined plasticity of several aspects of shape and trophic morphology in response to diets characteristic of either the derived benthic ecotype or the limnetic ecotype. When marine fish were reared on alternative diets, plasticity of head and mouth shape paralleled phenotypic divergence between the derived ecotypes, supporting the flexible stem model. Benthic and limnetic fish exhibited patterns of plasticity similar to those of the marine population; however, some differences in population means were present, as well as subtle differences in shape plasticity in the benthic population, indicating a role for genetic accommodation in this system.
Proceedings of the National Academy of Sciences, 2002
It is a mainstay of community ecology that local exclusion of species will result if competitive ... more It is a mainstay of community ecology that local exclusion of species will result if competitive pressures become too large. The pattern of exclusion may be complicated, but the qualitative orthodoxy has changed little since the pioneering work of Lotka, Volterra, and Gause—no two species can occupy the same niche. Stated in a more precise form, the higher the intensity of interspecific competition in an assemblage of species, the fewer the number of species that can coexist in perpetuity. We suggest that this orthodoxy results from “linear” thinking, and that if the classical equations are formulated more realistically with attendant nonlinearities, the orthodoxy breaks down and higher levels of competition may actually increase the likelihood that species will avoid competitive exclusion. Furthermore, this increased probability of coexistence at higher levels of competition is accompanied by characteristic dynamic patterns: ( i ) at lower levels of competition, after all extinctio...
Northeastern Naturalist, 2007
... 1988. Timber Rattlesnakes (Crotalus horridus) of the Pine Barrens: Their movement patterns an... more ... 1988. Timber Rattlesnakes (Crotalus horridus) of the Pine Barrens: Their movement patterns and habitat preference. ... In press Ecology of the Aruba Island Rattlesnake, Crotalus durissus unicolor. ... A field study of the spatial ecology and movements of a threatened snake species ...
Journal of Structural Biology, 2010
In this study, a quantitative investigation of the microstructure and composition of field-caught... more In this study, a quantitative investigation of the microstructure and composition of field-caught marine Gasterosteus aculeatus (threespine stickleback) armor is presented, which provides useful phylogenetic information and insights into biomechanical function. Micro-computed tomography (lCT) was employed to create full three-dimensional images of the dorsal spines and basal plate, lateral plates, pelvic girdle and spines and to assess structural and compositional properties such as the spatial distribution of thickness ($100-300 lm), the heterogeneous cross-sectional geometry (centrally thickened), plate-to-plate juncture and overlap ($50% of the plate width), and bone mineral density (634-748 HA/cm 3). The convolution of plate geometry in conjunction with plate-to-plate overlap allows a relatively constant armor thickness to be maintained throughout the assembly, promoting spatially homogeneous protection and thereby avoiding weakness at the armor unit interconnections. Plate-to-plate junctures act to register and join the plates while permitting compliance in sliding and rotation in selected directions. Mercury porosimetry was used to determine the pore size distribution and volume percent porosity of the lateral plates (20-35 vol.%) and spines (10-15 vol.%). SEM and lCT revealed a porous, sandwich-like cross-section beneficial for bending stiffness and strength at minimum weight. Back-scattered electron microscopy and energy dispersive X-ray analysis were utilized to quantify the weight percent mineral content (58-68%). Scanning electron microscopy and surface profilometry were used to characterize the interior and exterior surface topography (tubercles) of the lateral plates. The results obtained in this study are discussed in the context of mechanical function, performance, fitness, and survivability.
Journal of Medical Entomology, 2009
The importance of predation as a mortality factor in adult mosquitoes has received only limited a... more The importance of predation as a mortality factor in adult mosquitoes has received only limited attention in the scientiÞc literature. Despite the lack of consensus among researchers as to whether bats are important predators of mosquitoes, there have been no attempts to directly document the effect of bats on mosquito populations or behavior. We conducted an enclosure experiment to test the hypothesis that bats reduce the local abundance of ovipositing female mosquitoes by examining whether the northern long-eared bat (Myotis septentrionalis Trouessart) had an effect on Culex spp. (Diptera: Culicidae) oviposition, using naturally occurring mosquitoes, either through direct predation or trait mediated effects on mosquito behavior. We found a signiÞcant, 32% reduction in egg-laying activity associated with bat predation. ArtiÞcial oviposition habitats directly outside bat enclosures experienced no reduction in oviposition; we attributed the observed reduction in egg-laying activity to direct predation on ovipositing females by bats and not changes in mosquito behavior. In addition, we noted a decrease in the number of larval mosquitoes in enclosures exposed to bat predation. These results suggest the impact of aerial predators on pathogen transmission may be large, and warrants further scientiÞc investigation.
Integrative and Comparative Biology, 2012
In the past decade, there has been a resurgent interest in whether and how phenotypic plasticity ... more In the past decade, there has been a resurgent interest in whether and how phenotypic plasticity might impact evolutionary processes. Of fundamental importance is how the environment influences individual phenotypic development while simultaneously selecting among phenotypic variants in a population. Conceptual and theoretical treatments of the evolutionary implications of plasticity are numerous, as are criticisms of the conclusions. As such, the time is ripe for empirical evidence to catch up with theoretical predictions. To this end, I provide a summary of eight hypotheses at the core of this issue, highlighting various approaches by which they can be tested. My goal is to provide practical guidance to those seeking to understand the complex ways by which phenotypic plasticity can influence evolutionary innovation and diversification.
Trends in ecology & evolution, 2010
Phenotypic plasticity (the ability of a single genotype to produce multiple phenotypes in respons... more Phenotypic plasticity (the ability of a single genotype to produce multiple phenotypes in response to variation in the environment) is commonplace. Yet its evolutionary significance remains controversial, especially in regard to whether and how it impacts diversification and speciation. Here, we review recent theory on how plasticity promotes: (i) the origin of novel phenotypes, (ii) divergence among populations and species, (iii) the formation of new species and (iv) adaptive radiation. We also discuss the latest empirical support for each of these evolutionary pathways to diversification and identify potentially profitable areas for future research. Generally, phenotypic plasticity can play a largely underappreciated role in driving diversification and speciation.
Ethology, 2007
... The Effects of Relaxed and Reversed Selection by Predators on the Antipredator Behavior of th... more ... The Effects of Relaxed and Reversed Selection by Predators on the Antipredator Behavior of the Threespine Stickleback, Gasterosteus aculeatus. Alexis Messler,; Matthew A. Wund,; John A. Baker,; Susan A. Foster. ... 1993; Bell & Ortí 1994). ...