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Jonathan B. Losos - One of the best experts on this subject based on the ideXlab platform.
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hurricane effects on neotropical lizards span geographic and phylogenetic scales
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Colin M Donihue, Jonathan B. Losos, Hannah K Frank, Alex M Kowaleski, Adam C Algar, Simon Baeckens, Robert W Buchkowski, Anneclaire FabreAbstract:Extreme climate events such as droughts, cold snaps, and hurricanes can be powerful agents of natural selection, producing acute selective pressures very different from the everyday pressures acting on organisms. However, it remains unknown whether these infrequent but severe disruptions are quickly erased by quotidian selective forces, or whether they have the potential to durably shape biodiversity patterns across regions and clades. Here, we show that hurricanes have enduring evolutionary impacts on the morphology of anoles, a diverse Neotropical lizard clade. We first demonstrate a transgenerational effect of extreme selection on toepad area for two populations struck by hurricanes in 2017. Given this short-term effect of hurricanes, we then asked whether populations and species that more frequently experienced hurricanes have larger toepads. Using 70 y of historical hurricane data, we demonstrate that, indeed, toepad area positively correlates with hurricane activity for both 12 island populations of Anolis sagrei and 188 Anolis species throughout the Neotropics. Extreme climate events are intensifying due to climate change and may represent overlooked drivers of biogeographic and large-scale biodiversity patterns.
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phylogeographic and phenotypic outcomes of brown anole colonization across the caribbean provide insight into the beginning stages of an adaptive radiation
Journal of Evolutionary Biology, 2020Co-Authors: Robert Graham Reynolds, Richard E. Glor, Jason J Kolbe, Kevin De Queiroz, Alexis Harrison, Marta Lopezdarias, Veronica Gomez C Pourroy, Liam J Revell, Jonathan B. LososAbstract:Some of the most important insights into the ecological and evolutionary processes of diversification and speciation have come from studies of island adaptive radiations, yet relatively little research has examined how these radiations initiate. We suggest that Anolis sagrei is a candidate for understanding the origins of the Caribbean Anolis adaptive radiation and how a colonizing anole species begins to undergo allopatric diversification, phenotypic divergence and, potentially, speciation. We undertook a genomic and morphological analysis of representative populations across the entire native range of A. sagrei, finding that the species originated in the early Pliocene, with the deepest divergence occurring between western and eastern Cuba. Lineages from these two regions subsequently colonized the northern Caribbean. We find that at the broadest scale, populations colonizing areas with fewer closely related competitors tend to evolve larger body size and more lamellae on their toepads. This trend follows expectations for post-colonization divergence from progenitors and convergence in allopatry, whereby populations freed from competition with close relatives evolve towards common morphological and ecological optima. Taken together, our results show a complex history of ancient and recent Cuban diaspora with populations on competitor-poor islands evolving away from their ancestral Cuban populations regardless of their phylogenetic relationships, thus providing insight into the original diversification of colonist anoles at the beginning of the radiation. Our research also supplies an evolutionary framework for the many studies of this increasingly important species in ecological and evolutionary research.
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bridging the process pattern divide to understand the origins and early stages of adaptive radiation a review of approaches with insights from studies of Anolis lizards
Journal of Heredity, 2020Co-Authors: James T Stroud, Jonathan B. LososAbstract:Understanding the origins and early stages of diversification is one of the most elusive tasks in adaptive radiation research. Classical approaches, which aim to infer past processes from present-day patterns of biological diversity, are fraught with difficulties and assumptions. An alternative approach has been to study young clades of relatively few species, which may represent the putative early stages of adaptive radiation. However, it is difficult to predict whether those groups will ever reach the ecological and morphological disparity observed in the sorts of clades usually referred to as adaptive radiations, thereby making their utility in informing the early stages of such radiations uncertain. Caribbean Anolis lizards are a textbook example of an adaptive radiation; anoles have diversified independently on each of the 4 islands in the Greater Antilles, producing replicated radiations of phenotypically diverse species. However, the underlying processes that drove these radiations occurred 30-65 million years ago and so are unobservable, rendering major questions about how these radiations came to be difficult to tackle. What did the ancestral species of the anole radiation look like? How did new species arise? What processes drove adaptive diversification? Here, we review what we have learned about the cryptic early stages of adaptive radiation from studies of Anolis lizards, and how these studies have attempted to bridge the process-pattern divide of adaptive radiation research. Despite decades of research, however, fundamental questions linking eco-evolutionary processes to macroevolutionary patterns in anoles remain difficult to answer.
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quantifying movement behavior the first step of sexual selection in the lizard Anolis sagrei
bioRxiv, 2017Co-Authors: Ambika Kamath, Jonathan B. LososAbstract:How individuals move through their environment dictates which other individuals they encounter, determining their social and reproductive interactions and the extent to which they experience sexual selection. Specifically, females rarely have the option of mating with all males in a population -- they can only choose among the males they encounter. Further, quantifying phenotypic differences between the males that females encounter and those that sire females9 offspring lends insight into how social and reproductive interactions shape male phenotypes. We used an explicitly spatiotemporal Markov chain model to estimate the number of potential mates of Anolis sagrei lizards from their movement behavior, and used genetic paternity assignments to quantify sexual selection on males. Females frequently encountered and mated with multiple males, offering ample opportunity for female mate choice. Sexual selection favored males that were bigger and moved over larger areas, though the effect of body size cannot be disentangled from last-male precedence. Our approach corroborates some patterns of sexual selection previously hypothesized in anoles based on describing them as territorial, whereas other results, including female multiple mating itself, are at odds with territorial polygyny, offering insight into discrepancies in other taxa between behavioral and genetic descriptions of mating systems.
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semicircular canals in Anolis lizards ecomorphological convergence and ecomorph affinities of fossil species
Royal Society Open Science, 2017Co-Authors: Blake V Dickson, Jonathan B. Losos, Emma Sherratt, Stephanie E PierceAbstract:Anolis lizards are a model system for the study of adaptive radiation and convergent evolution. Greater Antillean anoles have repeatedly evolved six similar forms or ecomorphs: crown-giant, grass-bush, twig, trunk, trunk-crown and trunk-ground. Members of each ecomorph category possess a specific set of morphological, ecological and behavioural characteristics which have been acquired convergently. Here we test whether the semicircular canal system-the organ of balance during movement-is also convergent among ecomorphs, reflecting the shared sensory requirements of their ecological niches. As semicircular canal shape has been shown to reflect different locomotor strategies, we hypothesized that each Anolis ecomorph would have a unique canal morphology. Using three-dimensional semilandmarks and geometric morphometrics, semicircular canal shape was characterized in 41 Anolis species from the Greater Antilles and the relationship between canal shape and ecomorph grouping, phylogenetic history, size, head dimensions, and perch characteristics was assessed. Further, canal morphology of modern species was used to predict the ecomorph affinity of five fossil anoles from the Miocene of the Dominican Republic. Of the covariates tested, our study recovered ecomorph as the single-most important covariate of canal morphology in modern taxa; although phylogenetic history, size, and head dimensions also showed a small, yet significant correlation with shape. Surprisingly, perch characteristics were not found to be significant covariates of canal shape, even though they are important habitat variables. Using posterior probabilities, we found that the fossil anoles have different semicircular canals shapes to modern ecomorph groupings implying extinct anoles may have been interacting with their Miocene environment in different ways to modern Anolis species.
Richard E. Glor - One of the best experts on this subject based on the ideXlab platform.
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phylogeographic and phenotypic outcomes of brown anole colonization across the caribbean provide insight into the beginning stages of an adaptive radiation
Journal of Evolutionary Biology, 2020Co-Authors: Robert Graham Reynolds, Richard E. Glor, Jason J Kolbe, Kevin De Queiroz, Alexis Harrison, Marta Lopezdarias, Veronica Gomez C Pourroy, Liam J Revell, Jonathan B. LososAbstract:Some of the most important insights into the ecological and evolutionary processes of diversification and speciation have come from studies of island adaptive radiations, yet relatively little research has examined how these radiations initiate. We suggest that Anolis sagrei is a candidate for understanding the origins of the Caribbean Anolis adaptive radiation and how a colonizing anole species begins to undergo allopatric diversification, phenotypic divergence and, potentially, speciation. We undertook a genomic and morphological analysis of representative populations across the entire native range of A. sagrei, finding that the species originated in the early Pliocene, with the deepest divergence occurring between western and eastern Cuba. Lineages from these two regions subsequently colonized the northern Caribbean. We find that at the broadest scale, populations colonizing areas with fewer closely related competitors tend to evolve larger body size and more lamellae on their toepads. This trend follows expectations for post-colonization divergence from progenitors and convergence in allopatry, whereby populations freed from competition with close relatives evolve towards common morphological and ecological optima. Taken together, our results show a complex history of ancient and recent Cuban diaspora with populations on competitor-poor islands evolving away from their ancestral Cuban populations regardless of their phylogenetic relationships, thus providing insight into the original diversification of colonist anoles at the beginning of the radiation. Our research also supplies an evolutionary framework for the many studies of this increasingly important species in ecological and evolutionary research.
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Signals and Speciation: Anolis Dewlap Color as a Reproductive Barrier
Journal of Herpetology, 2017Co-Authors: Anthony J. Geneva, Sabina Noll, Richard E. GlorAbstract:Abstract The divergence of signals used in sexual selection and species recognition is thought to play an important role in speciation. As such, the striking diversity of dewlap color in Anolis lizards may have contributed to the diversification of this species-rich group. Whether the dewlap acts as a reproductive isolating barrier however remains unclear. We tested the prediction that the degree of dewlap divergence between the two closely related and highly polymorphic Hispaniolan trunk anoles Anolis distichus and Anolis brevirostris is correlated with genetic divergence and the frequency of hybridization in nature. We use integrative analyses of dewlap color variation and molecular genetics to investigate two pairs of localities where the species co-occur, including one pair of localities where the two species exhibit dissimilar dewlaps and a second pair of localities where they have similar dewlaps. At one site where species share similar dewlap coloration, we found evidence of hybridization and lower...
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determinism in the diversification of hispaniolan trunk ground anoles Anolis cybotes species complex
Evolution, 2013Co-Authors: Ian J Wang, Richard E. Glor, Katharina C Wollenberg, Jonathan B. LososAbstract:results to patterns observed at a deeper, macroevolutionary level. We tested whether evolution is a deterministic process with similar outcomes during different stages of the adaptive radiation of Anolis lizards. Using a clade of terrestrial–scansorial lizards in the genus Anolis, we inferred the adaptive basis of spatial variation among contemporary populations and tested whether axes of phenotypic differentiation among them mirror known axes of diversification at deeper levels of the anole radiation. Nonparallel change associated with genetic divergence explains the vast majority of geographic variation. However, we found phenotypic variation to be adaptive as confirmed by convergence in populations occurring in similar habitats in different mountain ranges. Morphological diversification among populations recurs deterministically along two axes of diversification previously identified in the anole radiation, but the characters involved differ from those involved in adaptation at higher levels of anole phylogeny.
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using genomic data to revisit an early example of reproductive character displacement in haitian Anolis lizards
Molecular Ecology, 2013Co-Authors: Luke D Mahler, Anthony J. Geneva, Shea M Lambert, Richard E. GlorAbstract:Abstract The pattern of reproductive character displacement (RCD)—in which traits associatedwith reproductive isolation are more different where two species occur together thanwhere they occur in isolation—is frequently attributed to reinforcement, a process duringwhich natural selection acting against maladaptive mating events leads to enhanced pre-zygotic isolation between species or incipient species. One of the first studies of RCD toinclude molecular genetic data was described 40 years ago in a complex of Haitian trunkanole lizards using a small number of allozyme loci. In this example, Anolis caudalisappears to experience divergence in the color and pattern of an extensible throat fan, ordewlap, in areas of contact with closely related species at the northern and southern lim-its of its range. However, this case study has been largely overlooked for decades; mean-while, explanations for geographic variation in dewlap color and pattern have focusedprimarily on adaptation to local signalling environments. We reinvestigate this exampleusing amplified fragment length polymorphism (AFLP) genome scans, mtDNA sequencedata, information on dewlap phenotypes and GIS data on environmental variation to testthe hypothesis of RCD generated by reinforcement in Haitian trunk anoles. Together,our phenotypic and genetic results are consistent with RCD at the southern and northernlimits of the range of A. caudalis. We evaluate the evidence for reinforcement as theexplanation for RCD in Haitian trunk anoles, consider alternative explanations andprovide suggestions for future work on the relationship between dewlap variation andspeciation in Haitian trunk anoles.Keywords: AFLP, character displacement, local adaptation, reinforcement, speciationReceived 4 October 2012; revision received 12 February 2013; accepted 14 February 2013
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asynchronous evolution of physiology and morphology in Anolis lizards
Evolution, 2013Co-Authors: Paul E Hertz, Jonathan B. Losos, Yuzo Arima, Alexis Harrison, Raymond B Huey, Richard E. GlorAbstract:Species-rich adaptive radiations typically diversify along several distinct ecological axes, each characterized by morphological, physiological, and behavioral adaptations. We test here whether different types of adaptive traits share similar patterns of evolution within a radiation by investigating patterns of evolution of morphological traits associated with microhabitat specialization and of physiological traits associated with thermal biology in Anolis lizards. Previous studies of anoles suggest that close relatives share the same "structural niche" (i.e., use the same types of perches) and are similar in body size and shape, but live in different "climatic niches" (i.e., use habitats with different insolation and temperature profiles). Because morphology is closely tied to structural niche and field active body temperatures are tied to climatic niches in Anolis, we expected phylogenetic analyses to show that morphology is more evolutionarily conservative than thermal physiology. In support of this hypothesis, we find (1) that thermal biology exhibits more divergence among recently diverged Anolis taxa than does morphology; and (2) diversification of thermal biology among all species often follows diversification in morphology. These conclusions are remarkably consistent with predictions made by anole biologists in the 1960s and 1970s.
Duncan J. Irschick - One of the best experts on this subject based on the ideXlab platform.
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the impact of tail loss on stability during jumping in green anoles Anolis carolinensis
Physiological and Biochemical Zoology, 2013Co-Authors: Gary B. Gillis, Chiyun Kuo, Duncan J. IrschickAbstract:AbstractLizards that undergo caudal autotomy experience a variety of consequences, including decreased locomotor performance in a number of cases. One mode of locomotion common to many arboreal lizard species is jumping, and yet little is known about the effects of autotomy on this locomotor mode. In this article we review recent literature demonstrating the importance of the lizard tail as an in-air stabilizer. First, we review work highlighting how a variety of lizards from diverse families can use their tails to control body position in midair. We then move on to cover recent work demonstrating how in at least one species, Anolis carolinensis, tail loss can lead to remarkable instabilities after takeoff during jumping. Such instabilities occur even when animals are jumping toward specific targets both below and above them, although individual variation in the response to tail loss is considerable. Finally, we report results from a study examining whether increased jumping experience after autotomy faci...
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take this broken tail and learn to jump the ability to recover from reduced in air stability in tailless green anole lizards Anolis carolinensis squamata dactyloidae
Biological Journal of The Linnean Society, 2012Co-Authors: Chiyun Kuo, Gary B. Gillis, Duncan J. IrschickAbstract:Locomotion is involved in various fitness‐related tasks, such as foraging, acquiring mates, and escaping from predators. Despite the importance of locomotor performance in determining fitness, animals often encounter situations in nature during which their locomotor performance is severely compromised. For animals that actively discard appendages as an anti‐predator strategy, the loss of appendages can cause a severe reduction in locomotor performance. However, whether animals can compensate for the impact on locomotor performance after autotomy is still unclear. A previous study has shown that tailless green anole lizards suffered from reduced in‐air stability during jumping. In this study, we monitored jump kinematics in three groups of Anolis carolinensis for five consecutive weeks to test two hypotheses: first, whether tailless green anoles can recover from reduced in‐air stability before their tails can regenerate; and second, whether gaining locomotor experience facilitates locomotor recovery. Our results revealed extensive individual variation in the ability to compensate for reduced in‐air stability. Some individuals did improve in‐air stability during the study period, whereas others showed no sign of improvement. Moreover, the acquisition of locomotor experience did not facilitate the recovery process. Our findings suggested that tail autotomy in green anoles probably imposes a long‐term fitness disadvantage. The utility of other compensatory mechanisms, such as altering behaviour, might play a role in natural populations to minimize the impact of autotomy on individual fitness. Our findings also shed light on the independent evolutionary losses of the ability to autotomize within lizards. Comparative studies which test whether species that autotomize more frequently/easily can better compensate for the effect of autotomy would be a fruitful direction of future research.
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Total recoil: perch compliance alters jumping performance and kinematics in green anole lizards (Anolis carolinensis)
Journal of Experimental Biology, 2012Co-Authors: C. A. Gilman, M. D. Bartlett, Gary B. Gillis, Duncan J. IrschickAbstract:Jumping is a common form of locomotion for many arboreal animals. Many species of the arboreal lizard genus Anolis occupy habitats in which they must jump to and from unsteady perches, e.g. narrow branches, vines, grass and leaves. Anoles therefore often use compliant perches that could alter jump performance. In this study we conducted a small survey of the compliance of perches used by the arboreal green anole Anolis carolinensis in the wild (N=54 perches) and then, using perches within the range of compliances used by this species, investigated how perch compliance (flexibility) affects the key jumping variables jump distance, takeoff duration, takeoff angle, takeoff speed and landing angle in A. carolinensis in the laboratory (N=11). We observed that lizards lost contact with compliant horizontal perches prior to perch recoil, and increased perch compliance resulted in decreased jump distance and takeoff speed, likely because of the loss of kinetic energy to the flexion of the perch. However, the most striking effect of perch compliance was an unexpected one; perch recoil following takeoff resulted in the lizards being struck on the tail by the perch, even on the narrowest perches. This interaction between the perch and the tail significantly altered body positioning during flight and landing. These results suggest that although the use of compliant perches in the wild is common for this species, jumping from these perches is potentially costly and may affect survival and behavior, particularly in the largest individuals.
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experimental test of predation and competition pressures on the green anole Anolis carolinensis in varying structural habitats
Journal of Herpetology, 2010Co-Authors: David M Mcmillan, Duncan J. IrschickAbstract:The Green Anole, Anolis carolinensis, has been widely studied in terms of its behavioral ecology. However, few studies have simultaneously compared the relative strengths of predation and male competition across temporal and spatial scales in Green Anoles, or other reptile species. We took an indirect experimental approach to compare these forces in Green Anoles by using attacks on clay models as a proxy for the relative intensity of predation and male competition. We measured the proportion of attacks on clay models in two divergent Green Anole populations with distinct habitats (discrete and continuous vegetation) across three seasons (fall, winter, and spring) and found strong evidence for spatial and temporal variation in the relative intensity of each component of selection. The frequency of bites from male Green Anoles was generally higher at an urban locality, whereas the frequency of bites from nonlizards was higher at a natural swamp locality. We also detected temporal variation in the intensity of these processes at both locations, with the intensity of male competition and predation changing in a concomitant fashion, the most intense periods occurring during the fall and spring months and the least intense during the winter months. Our results imply that mortality within some seasonal reptile species is composed of periods of relative calm punctuated by brief but intense ''one-two punch'' periods of selection.
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determinants of sexual differences in escape behavior in lizards of the genus Anolis a comparative approach
Integrative and Comparative Biology, 2007Co-Authors: Bieke Vanhooydonck, Anthony Herrel, Duncan J. IrschickAbstract:Males and females are known to differ in a whole suite of characteristics, such as morphology, physiology, ecology, and behavior. Intersexual differences are generally believed to arise because of differences in selective pressures on either sex. In this study, we investigated whether intersexual differences in escape behavior exist in lizards of the genus Anolis, and whether these could be explained by intersexual differences in body size and/or microhabitat use. To do so, we compared the behavioral response to an approaching human predator in the field in males and females of 12 Anolis species. We found that ecomorphs and sexes differ greatly with respect to escape behavior. Twig anoles have the shortest approach distance (i.e., distance between the observer and the lizard when it starts fleeing) and final distance (i.e., distance between the observer and the lizard when it stops moving), compared with the other ecomorphs. The distance fled, on the contrary, is greatest in twig anoles. Also, females flee less soon and run over shorter distances than do males. Since twig anoles are considered the most cryptic anoles, and females may be less conspicuous than males, these results corroborate the idea that well camouflaged animals allow predators to come closer. The interspecific variation in sexual dimorphism in escape behavior, however, cannot be explained by the interspecific variation in sexual size dimorphism or sexual dimorphism in microhabitat use. Thus, escape behavior appears determined by different factors in males and females.
Jason J Kolbe - One of the best experts on this subject based on the ideXlab platform.
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phylogeographic and phenotypic outcomes of brown anole colonization across the caribbean provide insight into the beginning stages of an adaptive radiation
Journal of Evolutionary Biology, 2020Co-Authors: Robert Graham Reynolds, Richard E. Glor, Jason J Kolbe, Kevin De Queiroz, Alexis Harrison, Marta Lopezdarias, Veronica Gomez C Pourroy, Liam J Revell, Jonathan B. LososAbstract:Some of the most important insights into the ecological and evolutionary processes of diversification and speciation have come from studies of island adaptive radiations, yet relatively little research has examined how these radiations initiate. We suggest that Anolis sagrei is a candidate for understanding the origins of the Caribbean Anolis adaptive radiation and how a colonizing anole species begins to undergo allopatric diversification, phenotypic divergence and, potentially, speciation. We undertook a genomic and morphological analysis of representative populations across the entire native range of A. sagrei, finding that the species originated in the early Pliocene, with the deepest divergence occurring between western and eastern Cuba. Lineages from these two regions subsequently colonized the northern Caribbean. We find that at the broadest scale, populations colonizing areas with fewer closely related competitors tend to evolve larger body size and more lamellae on their toepads. This trend follows expectations for post-colonization divergence from progenitors and convergence in allopatry, whereby populations freed from competition with close relatives evolve towards common morphological and ecological optima. Taken together, our results show a complex history of ancient and recent Cuban diaspora with populations on competitor-poor islands evolving away from their ancestral Cuban populations regardless of their phylogenetic relationships, thus providing insight into the original diversification of colonist anoles at the beginning of the radiation. Our research also supplies an evolutionary framework for the many studies of this increasingly important species in ecological and evolutionary research.
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hybridization and rapid differentiation after secondary contact between the native green anole Anolis carolinensis and the introduced green anole Anolis porcatus
Ecology and Evolution, 2019Co-Authors: Johanna E Wegener, Jessica N Pitaaquino, Jessica R Atutubo, Adam Moreno, Jason J KolbeAbstract:In allopatric species, reproductive isolation evolves through the accumulation of genetic incompatibilities. The degree of divergence required for complete reproductive isolation is highly variable across taxa, which makes the outcome of secondary contact between allopatric species unpredictable. Since before the Pliocene, two species of Anolis lizards, Anolis carolinensis and Anolis porcatus, have been allopatric, yet this period of independent evolution has not led to substantial species-specific morphological differentiation, and therefore, they might not be reproductively isolated. In this study, we determined the genetic consequences of localized, secondary contact between the native green anole, A. carolinensis, and the introduced Cuban green anole, A. porcatus, in South Miami. Using 18 microsatellite markers, we found that the South Miami population formed a genetic cluster distinct from both parental species. Mitochondrial DNA revealed maternal A. porcatus ancestry for 35% of the individuals sampled from this population, indicating a high degree of cytonuclear discordance. Thus, hybridization with A. porcatus, not just population structure within A. carolinensis, may be responsible for the genetic distinctiveness of this population. Using tree-based maximum-likelihood analysis, we found support for a more recent, secondary introduction of A. porcatus to Florida. Evidence that ~33% of the nuclear DNA resulted from a secondary introduction supports the hybrid origin of the green anole population in South Miami. We used multiple lines of evidence and multiple genetic markers to reconstruct otherwise cryptic patterns of species introduction and hybridization. Genetic evidence for a lack of reproductive isolation, as well as morphological similarities between the two species, supports revising the taxonomy of A. carolinensis to include A. porcatus from western Cuba. Future studies should target the current geographic extent of introgression originating from the past injection of genetic material from Cuban green anoles and determine the consequences for the evolutionary trajectory of green anole populations in southern Florida.
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an experimental evaluation of foraging decisions in urban and natural forest populations of Anolis lizards
Urban Ecosystems, 2017Co-Authors: Zachary A Chejanovski, Kevin J Avilesrodriguez, Oriol Lapiedra, Evan L Preisser, Jason J KolbeAbstract:Foraging decisions reflect a trade-off between the benefits of acquiring food and the costs of movement. Changes in the biotic and abiotic environment associated with urbanization can alter this trade-off and modify foraging decisions. We experimentally manipulated foraging opportunities for two Anolis lizard species – the brown anole (A. sagrei) in Florida and the crested anole (A. cristatellus) in Puerto Rico – to assess whether foraging behavior differs between habitats varying in their degree of urbanization. In both urban and natural forest habitats, we measured the latency of perched anoles to feed from an experimental feeding tray. We manipulated perch availability and predator presence, while also taking into account population (e.g., conspecific density) and individual-level factors (e.g., body temperature) to evaluate whether and how these contribute to between-habitat differences in foraging behavior. In both species, urban anoles had longer latencies to feed and lower overall response rates compared to lizards from forests. Urban anoles were also larger (i.e., snout-vent length and mass) in both species and urban A. sagrei were in better body condition than the natural forest population. We postulate that the observed patterns in foraging behavior are driven by differences in perceived predation risk, foraging motivation, or neophobia. Although we are unable to identify the mechanism(s) driving these differences, the substantial differences in urban versus forest anole foraging behavior emphasizes the importance of understanding how urbanization influences animal populations and their persistence in anthropogenically-modified environments.
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predation risk perception food density and conspecific cues shape foraging decisions in a tropical lizard
PLOS ONE, 2015Co-Authors: Maximilian Drakeley, Oriol Lapiedra, Jason J KolbeAbstract:When foraging, animals can maximize their fitness if they are able to tailor their foraging decisions to current environmental conditions. When making foraging decisions, individuals need to assess the benefits of foraging while accounting for the potential risks of being captured by a predator. However, whether and how different factors interact to shape these decisions is not yet well understood, especially in individual foragers. Here we present a standardized set of manipulative field experiments in the form of foraging assays in the tropical lizard Anolis cristatellus in Puerto Rico. We presented male lizards with foraging opportunities to test how the presence of conspecifics, predation-risk perception, the abundance of food, and interactions among these factors determines the outcome of foraging decisions. In Experiment 1, anoles foraged faster when food was scarce and other conspecifics were present near the feeding tray, while they took longer to feed when food was abundant and when no conspecifics were present. These results suggest that foraging decisions in anoles are the result of a complex process in which individuals assess predation risk by using information from conspecific individuals while taking into account food abundance. In Experiment 2, a simulated increase in predation risk (i.e., distance to the feeding tray) confirmed the relevance of risk perception by showing that the use of available perches is strongly correlated with the latency to feed. We found Puerto Rican crested anoles integrate instantaneous ecological information about food abundance, conspecific activity and predation risk, and adjust their foraging behavior accordingly.
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phylogenetic analysis of the evolution of the niche in lizards of the Anolis sagrei group
Ecology, 2006Co-Authors: Jason H Knouft, Richard E. Glor, Jonathan B Losos, Jason J KolbeAbstract:Recent advances in ecological niche modeling (ENM) algorithms, in conjunction with increasing availability of geographic information system (GIS) data, allow species' niches to be predicted over broad geographic areas using environmental characteristics associated with point localities for a given species. Consequently, the examination of how niches evolve is now possible using a regionally inclusive multivariate approach to characterize the environmental requirements of a species. Initial work that uses this approach has suggested that niche evolution is characterized by conservatism: the more closely related species are, the more similar are their niches. We applied a phylogenetic approach to examine niche evolution during the radiation of Cuban trunk-ground anoles (Anolis sagrei group), which has produced 15 species in Cuba. We modeled the niche of 11 species within this group using the WhyWhere ENM algorithm and examined the evolution of the niche using a phylogeny based on 1500 base pairs of mitocho...
Allan Larson - One of the best experts on this subject based on the ideXlab platform.
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out of cuba overwater dispersal and speciation among lizards in the Anolis carolinensis subgroup
Molecular Ecology, 2005Co-Authors: Richard E. Glor, Jonathan B. Losos, Allan LarsonAbstract:Overwater dispersal and subsequent allopatric speciation contribute importantly to the species diversity of West Indian Anolis lizards and many other island radiations. Here we use molecular phylogenetic analyses to assess the contribution of overwater dispersal to diversification of the Anolis carolinensis subgroup, a clade comprising nine canopy-dwelling species distributed across the northern Caribbean. Although this clade includes some of the most successful dispersers and colonists in the anole radiation, the taxonomic status and origin of many endemic populations have been ambiguous. New mitochondrial and nuclear DNA sequences from four species occurring on small islands or island banks ( Anolis brunneus , Anolis longiceps , Anolis maynardi , Anolis smaragdinus ) and one species from the continental United States ( A. carolinensis ) are presented and analysed with homologous sequences sampled from related species on Cuba ( Anolis allisoni and Anolis porcatus ). Our analyses confirm that all five non-Cuban species included in our study represent distinct, independently evolving lineages that warrant continued species recognition. Moreover, our results support Ernest Williams’s hypothesis that all of these species originated by overseas colonization from Cuban source populations. However, contrary to Williams’s hypothesis of Pleistocene dispersal, most colonization events leading to speciation apparently occurred earlier, in the late Miocene–Pliocene. These patterns suggest that overwater dispersal among geologically distinct islands and island banks is relatively infrequent in anoles and has contributed to allopatric speciation. Finally, our results suggest that large Greater Antillean islands serve as centres of origin for regional species diversity.
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mainland colonization by island lizards
Journal of Biogeography, 2005Co-Authors: Kirsten E. Nicholson, Richard E. Glor, Jason J Kolbe, Allan Larson, Blair S Hedges, Jonathan B. LososAbstract:Aim We investigate biogeographic relationships within the lizard genus Anolis Daudin, 1802 to test the hypothesis that the mainland (Central and South American) Norops-clade species descended from a West Indian Anolis ancestor. Previous hypotheses have suggested that close island relatives of mainland Norops species (the Cuban Anolis sagrei and Jamaican A. grahami series) represent over-water dispersal from a mainland ancestor. These previous hypotheses predict that the A. sagrei and A. grahami series should be phylogenetically nested within a Norops clade whose ancestral geography traces to the mainland. If Norops is West Indian in origin, then West Indian species should span the deepest phylogenetic divergences within the Norops clade. Location Central and South America and West Indian islands. Methods The phylogenetic relationships of Anolis lizards are reconstructed from aligned DNA sequences using both parsimony and Bayesian approaches. Hypotheses are tested in two ways: (1) by reconstructing the ancestral geographic location for the Norops clade using Pagel & Lutzoni's (2002) Bayesian approach, and (2) by testing alternative topological arrangements via Wilcoxon Signed-Ranks tests (Templeton, 1983) and Shimodaira–Hasegawa tests (Shimodaira & Hasegawa, 1999). Results Our evidence supports an origin of mainland Norops anoles from a West Indian ancestor. A West Indian ancestor to the Norops clade is statistically supported, and alternatives to the biogeographic pattern [Cuban (Jamaican, Mainland)] are statistically rejected by Shimodaira–Hasegawa tests, although not by Wilcoxon Signed-Ranks tests. Main conclusions Our data support the hypothesis of a West Indian origin for mainland Norops. This result contradicts previous hypotheses and suggests that island forms may be an important source for mainland biodiversity.
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phylogenetic analysis of ecological and morphological diversification in hispaniolan trunk ground anoles Anolis cybotes group
Evolution, 2003Co-Authors: Richard E. Glor, Jonathan B. Losos, Jason J Kolbe, Allan Larson, Robert PowellAbstract:Anolis lizards in the Greater Antilles partition the structural microhabitats available at a given site into four to six distinct categories. Most microhabitat specialists, or ecomorphs, have evolved only once on each island, yet closely related species of the same ecomorph occur in different geographic macrohabitats across the island. The extent to which closely related species of the same ecomorph have diverged to adapt to different geographic macro- habitats is largely undocumented. On the island of Hispaniola, members of the Anolis cybotes species group belong to the trunk-ground ecomorph category. Despite evolutionary stability of their trunk-ground microhabitat, populations of the A. cybotes group have undergone an evolutionary radiation associated with geographically distinct macrohabitats. A combined phylogeographic and morphometric study of this group reveals a strong association between macrohabitat type and morphology independent of phylogeny. This association results from long-term morphological evolutionary stasis in populations associated with mesic-forest environments (A. c. cybotes and A. marcanoi) and predictable morphometric changes associated with entry into new macrohabitat types (i.e., xeric forests, high-altitude pine forest, rock outcrops). Phylogeographic analysis of 73 new mitochondrial DNA sequences (1921 aligned sites) sampled from 68 geographic populations representing 12 recognized species and subspecies diagnoses 16 allopatric or parapatric groupings of populations differing from each other by 5-18% sequence divergence. At least some of these groupings appear to have attained species-level divergence from others. Evolutionary specialization to different macrohabitat types may be a major factor in the evolutionary diversification of Greater Antillean anoles.
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phylogenetic relationships and tempo of early diversification in Anolis lizards
Systematic Biology, 1999Co-Authors: Todd R Jackman, Allan Larson, Kevin De Queiroz, Jonathan B. LososAbstract:We examine phylogenetic relationships among anoles using mitochondrial DNA se- quences from the NADH dehydrogenase subunit 2 gene (ND2) andve transfer-RNA genes repre- senting 1,455 alignable base positions and 866 phylogenetically informative characters (parsimony criterion). We also present 16 morphological characters for phylogenetic analysis. Our analyses yielded poorly-supported nodes deep in the anole tree but many well-supported nodes for more recent phylogenetic divergences. We test the hypothesis that the major clades of anoles form a hard polytomy and present a general statistical framework for testing hypotheses of simultaneous branching of lineages by using molecular sequence data. Our results suggest that rapid diversi- �cation early in the evolutionary history of anoles explains why numerous researchers have had difculty reconstructing well-supported dichotomous phylogenetic trees for anoles. ( Anolis; mito- chondrial DNA; parametric bootstrap; permutation test; phylogeny; polytomy.)