Animals can differ in their individual movement behaviors during their daily displacements.Studies of animal movement patterns often disregard the need to understand individual variation in these patterns and the role...Animals can differ in their individual movement behaviors during their daily displacements.Studies of animal movement patterns often disregard the need to understand individual variation in these patterns and the role of this variation in shaping population distributions of movements.To assess the link between individual movements and population distributions,we radio-tracked 13 Fowler's Toads Anaxyrus fowleri in Long Point,Ontario,Canada,after their breeding season.We recorded individual coordinates every 30 min,from the moment they emerged from their burrows around dusk until they burrowed in the morning,and obtained a total of 157 movements.We used the resulting series of step lengths and turning angles in a Hidden Markov Model to estimate movement type as"directed"or"non-directed"We also assigned to each encounter one of 3 space-dependent movement states:"foraging""in transit'or"searching"and found that movement type and state switched within individuals irrespective of time during a single night.We find that switching between movement types varied throughout the night,leading to stochastic within-individual variation in movements,and the distribution of movement distances differed significantly among individuals.Movement states,however,were time-dependent,suggesting displacement routines were similar across individuals.Variation in movement behavior within individuals scales up to result in variation among individuals which,in turn,was found to shape the distribution of the sampled population.Our findings therefore underline the importance of a multi-scale approach in the study of movement.展开更多
An individual-based model, EcoSim, was employed to investigate if specialized resource use could promote sympatric speciation. Prey individuals in the original version of EcoSim were supplied with a single primary foo...An individual-based model, EcoSim, was employed to investigate if specialized resource use could promote sympatric speciation. Prey individuals in the original version of EcoSim were supplied with a single primary food resource. A dual resource version with different food resources (Food 1 and Food 2) was also developed to create favorable conditions for the emergence of specialized food consumption among prey individuals. The single resource version was used as the control to determine the impact of the presence of multiple food resources on the occurrence of sympatric speciation. Each unit of Food 2 contained a higher amount of energy than Food 1, and Food 1 was more accessible than Food 2. Initially, prey individuals mostly fed on Food 1. How-ever, after the emergence of food specialization, the consumption rate of Food 2 signifi-cantly exceeded the consumption rate of Food 1;although prey individuals more frequently encountered Food 1. While sympatric speciation was observed in the dual resource version runs, we could not identify any sympatric species in the single resource version runs. Machine learning techniques were also employed to identify the most influential initial conditions leading to sympatric speciation. According to the obtained results, in most lineages sympatric speciation occurred at the beginning of the food specialization pro-cess. When the lineage had a high special diversity, the lineage needed two different criteria to diverge sympatrically: possessing high genetic diversity and a large population size. In support of previous findings, this study demonstrated that the most accurate determination of initial conditions leading to sympatric speciation can be obtained from lineages that are at the beginning of the divergence process. In conclusion, this study indicated that divergent foraging behavior could potentially lead to the sympatric emergence of new species in the absence of geographic isolation.展开更多
Until the advent of phylogenomics,the atypical morphology of extant represen-tatives of the insect orders Grylloblattodea(ice-crawlers)and Mantophasmatodea(gladi-ators)had confounding effects on efforts to resolve the...Until the advent of phylogenomics,the atypical morphology of extant represen-tatives of the insect orders Grylloblattodea(ice-crawlers)and Mantophasmatodea(gladi-ators)had confounding effects on efforts to resolve their placement within Polyneoptera.This recent research has unequivocally shown that these species-poor groups are closely related and form the clade Xenonomia.Nonetheless,divergence dates of these groups re-main poorly constrained,and their evolutionary history debated,as the few well-identified fossils,characterized by a suite of morphological features similar to that of extant forms,are comparatively young.Notably,the extant forms of both groups are wingless,whereas most of the pre-Cretaceous insect fossil record is composed of winged insects,which represents a major shortcoming of the taxonomy.Here,we present new specimens em-bedded in mid-Cretaceous amber from Myanmar and belonging to the recently described species Aristovia danili.The abundant material and pristine preservation allowed a de-tailed documentation of the morphology of the species,including critical head features.Combined with a morphological data set encompassing all Polyneoptera,these new data unequivocally demonstrate that A.danili is a winged stem Grylloblattodea.This discov-ery demonstrates that winglessness was acquired independently in Grylloblattodea and Mantophasmatodea.Concurrently,wing apomorphic traits shared by the new fossil and earlier fossils demonstrate that a large subset of the former Protorthoptera"assemblage,representing a third of all known insect species in some Permian localities,are genuine representatives of Xenonomia.Data from the fossil record depict a distinctive evolution-ary trajectory,with the group being both highly diverse and abundant during the Permian but experiencing a severe decline from the Triassic onwards.展开更多
Evaluating whether hybrid zones are stable or mobile can provide novelinsights for evolution and conservation biology. Butterflies exhibit high sensitivity to envi-ronmental changes and represent an important model sy...Evaluating whether hybrid zones are stable or mobile can provide novelinsights for evolution and conservation biology. Butterflies exhibit high sensitivity to envi-ronmental changes and represent an important model system for the study of hybrid zoneorigins and maintenance. Here, we review the literature exploring butterfly hybrid zones,with a special focus on their spatiotemporal dynamics and the potential mechanisms thatcould lead to their movement or stability. We then compare different lines of evidenceused to investigate hybrid zone dynamics and discuss the strengths and weaknesses ofeach approach. Our goal with this review is to reveal general conditions associated withthe stability or mobility of butterfly hybrid zones by synthesizing evidence obtained us-ing different types of data sampled across multiple regions and spatial scales. Finally, wediscuss spatiotemporal dynamics in the context of a speciation/divergence continuum, therelevance of hybrid zones for conservation biology, and recommend key topics for futureinvestigation.展开更多
基金funded by grants from the Fonds de Recherche du Quebec-Nature et Technologies(FRQNT)to NJthe Ontario Ministry of Natural Resources and Forestrythe Ontario Ministry of Environment,Conservation and Parks,and the Natural Sciences and Engineering Research Council(NSERC)of Canada to DMG.
文摘Animals can differ in their individual movement behaviors during their daily displacements.Studies of animal movement patterns often disregard the need to understand individual variation in these patterns and the role of this variation in shaping population distributions of movements.To assess the link between individual movements and population distributions,we radio-tracked 13 Fowler's Toads Anaxyrus fowleri in Long Point,Ontario,Canada,after their breeding season.We recorded individual coordinates every 30 min,from the moment they emerged from their burrows around dusk until they burrowed in the morning,and obtained a total of 157 movements.We used the resulting series of step lengths and turning angles in a Hidden Markov Model to estimate movement type as"directed"or"non-directed"We also assigned to each encounter one of 3 space-dependent movement states:"foraging""in transit'or"searching"and found that movement type and state switched within individuals irrespective of time during a single night.We find that switching between movement types varied throughout the night,leading to stochastic within-individual variation in movements,and the distribution of movement distances differed significantly among individuals.Movement states,however,were time-dependent,suggesting displacement routines were similar across individuals.Variation in movement behavior within individuals scales up to result in variation among individuals which,in turn,was found to shape the distribution of the sampled population.Our findings therefore underline the importance of a multi-scale approach in the study of movement.
文摘An individual-based model, EcoSim, was employed to investigate if specialized resource use could promote sympatric speciation. Prey individuals in the original version of EcoSim were supplied with a single primary food resource. A dual resource version with different food resources (Food 1 and Food 2) was also developed to create favorable conditions for the emergence of specialized food consumption among prey individuals. The single resource version was used as the control to determine the impact of the presence of multiple food resources on the occurrence of sympatric speciation. Each unit of Food 2 contained a higher amount of energy than Food 1, and Food 1 was more accessible than Food 2. Initially, prey individuals mostly fed on Food 1. How-ever, after the emergence of food specialization, the consumption rate of Food 2 signifi-cantly exceeded the consumption rate of Food 1;although prey individuals more frequently encountered Food 1. While sympatric speciation was observed in the dual resource version runs, we could not identify any sympatric species in the single resource version runs. Machine learning techniques were also employed to identify the most influential initial conditions leading to sympatric speciation. According to the obtained results, in most lineages sympatric speciation occurred at the beginning of the food specialization pro-cess. When the lineage had a high special diversity, the lineage needed two different criteria to diverge sympatrically: possessing high genetic diversity and a large population size. In support of previous findings, this study demonstrated that the most accurate determination of initial conditions leading to sympatric speciation can be obtained from lineages that are at the beginning of the divergence process. In conclusion, this study indicated that divergent foraging behavior could potentially lead to the sympatric emergence of new species in the absence of geographic isolation.
基金This work was supported by the National Natural Science Foundation of China(no.42272004,42288201,32020103006).
文摘Until the advent of phylogenomics,the atypical morphology of extant represen-tatives of the insect orders Grylloblattodea(ice-crawlers)and Mantophasmatodea(gladi-ators)had confounding effects on efforts to resolve their placement within Polyneoptera.This recent research has unequivocally shown that these species-poor groups are closely related and form the clade Xenonomia.Nonetheless,divergence dates of these groups re-main poorly constrained,and their evolutionary history debated,as the few well-identified fossils,characterized by a suite of morphological features similar to that of extant forms,are comparatively young.Notably,the extant forms of both groups are wingless,whereas most of the pre-Cretaceous insect fossil record is composed of winged insects,which represents a major shortcoming of the taxonomy.Here,we present new specimens em-bedded in mid-Cretaceous amber from Myanmar and belonging to the recently described species Aristovia danili.The abundant material and pristine preservation allowed a de-tailed documentation of the morphology of the species,including critical head features.Combined with a morphological data set encompassing all Polyneoptera,these new data unequivocally demonstrate that A.danili is a winged stem Grylloblattodea.This discov-ery demonstrates that winglessness was acquired independently in Grylloblattodea and Mantophasmatodea.Concurrently,wing apomorphic traits shared by the new fossil and earlier fossils demonstrate that a large subset of the former Protorthoptera"assemblage,representing a third of all known insect species in some Permian localities,are genuine representatives of Xenonomia.Data from the fossil record depict a distinctive evolution-ary trajectory,with the group being both highly diverse and abundant during the Permian but experiencing a severe decline from the Triassic onwards.
文摘Evaluating whether hybrid zones are stable or mobile can provide novelinsights for evolution and conservation biology. Butterflies exhibit high sensitivity to envi-ronmental changes and represent an important model system for the study of hybrid zoneorigins and maintenance. Here, we review the literature exploring butterfly hybrid zones,with a special focus on their spatiotemporal dynamics and the potential mechanisms thatcould lead to their movement or stability. We then compare different lines of evidenceused to investigate hybrid zone dynamics and discuss the strengths and weaknesses ofeach approach. Our goal with this review is to reveal general conditions associated withthe stability or mobility of butterfly hybrid zones by synthesizing evidence obtained us-ing different types of data sampled across multiple regions and spatial scales. Finally, wediscuss spatiotemporal dynamics in the context of a speciation/divergence continuum, therelevance of hybrid zones for conservation biology, and recommend key topics for futureinvestigation.
