Journal Articles: Present - 2014

Journal Article
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T. Ingram, A. Harrison, D.L. Mahler, M. R. d. Castañeda, R.E. Glor, A. Herrel, Y.E. Stuart, and J. B. Losos. 11/17/2016. “Comparative Tests of the Role of Dewlap Size in Anolis Lizard Speciation.” Proceedings of the Royal Society of London B, 283.
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S. C. Campbell-Staton, S. V. Edwards, and J. B. Losos. 10/2016. “Climate-mediated Adaptation after mainland colonization of an ancestrally subtropical islan lizard, Anolis carolinensis.” Journal of Evolutionary Biology, 10, 29: 2168-2180.
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James T. Stroud and Jonathan B. Losos. 9/30/2016. “Ecological Opportunity and Adaptive Radiation.” Annual Review of Ecology, Evolution, and Systematics, 47: 507-32. Publisher's Version
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J.J. Kolbe, P. Van Middlesworth, A.C. Battles, J.T. Stroud, B. Buffum, R.T.T. Forman, and J. B. Losos. 2016. “Determinants of spread in an urban landscape by an introduced lizard..” Landscape Ecology.
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A.L. Jaffe, S. C. Campbell-Staton, and J. B. Losos. 2016. “Geographical variation in morphology and its environmental correlates in a widespread North American lizard, Anolis carolinensis (Squamata: Dactyloidae)..” Biological Journal of the Linnean Society, 117: 760-774.
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A. Wittorski, J. B. Losos, and A. Herrel. 2016. “Proximate determinants of bite force in Anolis lizards..” Journal of Anatomy, 228: 85-95.
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S. Scarpetta, L. Gray, A. Nieto-Montes de Oca, M.d.R. Castañeda, A. Herrel, J. B. Losos, R. Luna-Reyes, N. Jiménez Lang, and S. Poe. 2015. “Morphology and ecology of the Mexican cave anole Anolis Alvarezdeltoroi..” Mesoamerican Herpetology, 2: 260-268.
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E. Sherratt, M.d.R. Castañeda, R. J. Garwood, D.L. Mahler, T. J. Sanger, A. Herrel, K. de Queiroz, and J. B. Losos. 2015. “Amber fossils demonstrate deep-time stability of Caribbean lizard communities.” PNAS, Early Edition. Supplementary video
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A.S. Harrison, L. J. Revell, and J. B. Losos. 2015. “Correlated evolution of microhabitat, morphology, and behavior in West Indian Anolis lizards: a test of the habitat matrix model..” Behaviour, 152: 1187-1207.
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Julia Klaczko, Travis Ingram, and J. B. Losos. 2015. “Genitals evolve faster then other traits in Anolis lizards..” Journal of Zoology, 295: 44-48.
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J.E. Wegener, G.E.A. Gartner, and J. B. Losos. 2014. “Lizard scales in an adaptive radiation: variation in scale number follows climatic and structural habitat diversity in Anolis Lizards..” Biological Journal of the Linnean Society, 113: 570-579.
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M.d.R. Castañeda, E. Sherratt, and J. B. Losos. 2014. “The Mexican amber anole, Anolis electrum, within a phylogenetic context: implications for the origins of Caribbean anoles..” Biological Journal of the Linnean Society, 172: 133-144.
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M. R. Helmus, D.L. Mahler, and J. B. Losos. 2014. “Island biogeography of the Anthropocene.” Nature, 513: 543-6. Abstract

For centuries, biogeographers have examined the factors that produce patterns of biodiversity across regions. The study of islands has proved particularly fruitful and has led to the theory that geographic area and isolation influence species colonization, extinction and speciation such that larger islands have more species and isolated islands have fewer species (that is, positive species-area and negative species-isolation relationships). However, experimental tests of this theory have been limited, owing to the difficulty in experimental manipulation of islands at the scales at which speciation and long-distance colonization are relevant. Here we have used the human-aided transport of exotic anole lizards among Caribbean islands as such a test at an appropriate scale. In accord with theory, as anole colonizations have increased, islands impoverished in native species have gained the most exotic species, the past influence of speciation on island biogeography has been obscured, and the species-area relationship has strengthened while the species-isolation relationship has weakened. Moreover, anole biogeography increasingly reflects anthropogenic rather than geographic processes. Unlike the island biogeography of the past that was determined by geographic area and isolation, in the Anthropocene--an epoch proposed for the present time interval--island biogeography is dominated by the economic isolation of human populations.

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Y.E. Stuart, T. S. Campbell, P. A. Hohenlohe, R. G. Reynolds, L. J. Revell, and J. B. Losos. 2014. “Rapid evolution of a native species following invasion by a congener.” ScienceScienceScience, 346: 463-6. Abstract

In recent years, biologists have increasingly recognized that evolutionary change can occur rapidly when natural selection is strong; thus, real-time studies of evolution can be used to test classic evolutionary hypotheses directly. One such hypothesis is that negative interactions between closely related species can drive phenotypic divergence. Such divergence is thought to be ubiquitous, though well-documented cases are surprisingly rare. On small islands in Florida, we found that the lizard Anolis carolinensis moved to higher perches following invasion by Anolis sagrei and, in response, adaptively evolved larger toepads after only 20 generations. These results illustrate that interspecific interactions between closely related species can drive evolutionary change on observable time scales.

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M. M. Munoz, M. A. Stimola, A. C. Algar, A. Conover, A. J. Rodriguez, M. A. Landestoy, G. S. Bakken, and J. B. Losos. 2014. “Evolutionary stasis and lability in thermal physiology in a group of tropical lizards.” Proceedings of the Royal Society of London B, 281: 20132433. Abstract

Understanding how quickly physiological traits evolve is a topic of great interest, particularly in the context of how organisms can adapt in response to climate warming. Adjustment to novel thermal habitats may occur either through behavioural adjustments, physiological adaptation or both. Here, we test whether rates of evolution differ among physiological traits in the cybotoids, a clade of tropical Anolis lizards distributed in markedly different thermal environments on the Caribbean island of Hispaniola. We find that cold tolerance evolves considerably faster than heat tolerance, a difference that results because behavioural thermoregulation more effectively shields these organisms from selection on upper than lower temperature tolerances. Specifically, because lizards in very different environments behaviourally thermoregulate during the day to similar body temperatures, divergent selection on body temperature and heat tolerance is precluded, whereas night-time temperatures can only be partially buffered by behaviour, thereby exposing organisms to selection on cold tolerance. We discuss how exposure to selection on physiology influences divergence among tropical organisms and its implications for adaptive evolutionary response to climate warming.

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T. J. Sanger, S. M. Seav, M. Tokita, R. B. Langerhans, L. M. Ross, J. B. Losos, and A. Abzhanov. 2014. “The oestrogen pathway underlies the evolution of exaggerated male cranial shapes in Anolis lizards.” Proceedings of the Royal Society of London B, 281: 20140329. Abstract

Sexual dimorphisms vary widely among species. This variation must arise through sex-specific evolutionary modifications to developmental processes. Anolis lizards vary extensively in their expression of cranial dimorphism. Compared with other Anolis species, members of the carolinensis clade have evolved relatively high levels of cranial dimorphism; males of this clade have exceptionally long faces relative to conspecific females. Developmentally, this facial length dimorphism arises through an evolutionarily novel, clade-specific strategy. Our analyses herein reveal that sex-specific regulation of the oestrogen pathway underlies evolution of this exaggerated male phenotype, rather than the androgen or insulin growth factor pathways that have long been considered the primary regulators of male-biased dimorphism among vertebrates. Our results suggest greater intricacy in the genetic mechanisms that underlie sexual dimorphisms than previously appreciated.

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D. S. Steinberg, J. B. Losos, T. W. Schoener, D. A. Spiller, J.J. Kolbe, and M. Leal. 2014. “Predation-associated modulation of movement-based signals by a Bahamian lizard.” Proceedings of the National Academy of Sciences of the United States of America, 111: 9187-92. Abstract

Signaling individuals must effectively capture and hold the attention of intended conspecific receivers while limiting eavesdropping by potential predators. A possible mechanism for achieving this balance is for individuals to modulate the physical properties of their signals or to alter the proportion of time spent signaling, depending upon local levels of predation pressure. We test the hypothesis that prey can alter their visual signaling behavior to decrease conspicuousness and potentially limit predation risk via modulation of signal properties or display rate. To do so, we conducted a manipulative experiment in nature to evaluate the possible effect of predation pressure on the physical properties of movement-based signals and on the proportion of time spent signaling by using a well-understood predator-prey system in the Bahamas, the semiarboreal lizard Anolis sagrei, and one of its main predators, the curly-tailed lizard Leiocephalus carinatus. We find that on islands onto which the predator was introduced, male anoles reduce the maximum amplitude of head-bob displays but not the proportion of time spent signaling, in comparison with control islands lacking the predator. This reduction of amplitude also decreases signal active space, which might alter the reproductive success of signaling individuals. We suggest that future studies of predator-prey interactions consider the risk effects generated by changes in signals or signaling behavior to fully determine the influence of predation pressure on the dynamics of prey populations.

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K. E. Crandell, A. Herrel, M. Sasa, J. B. Losos, and K. Autumn. 2014. “Stick or grip? Co-evolution of adhesive toepads and claws in Anolis lizards.” Zoology, 117: 363-9. Abstract

Exploring the relationship between phenotype and performance in an ecological and evolutionary context is crucial to understanding the adaptive nature of phenotypic traits. Despite their ubiquity in vertebrates, few studies have examined the functional and ecological significance of claw morphologies. Here we examine the adhesive toepad and claw system of Anolis lizards. Claw characters are significantly different between lizards classified as arboreal (perch height>/=1m) and non-arboreal (perch height<1m). Arboreal species possess significantly higher and longer claws, and show trends toward decreased claw curvature and wider claw tip angles. Toepad size and claw length and height are tightly correlated with each other and with perch height, suggesting that the adhesive toepad and gripping claw have co-evolved to accommodate different habitats. The functional morphology and evolution of claws are ripe areas for future investigation.

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