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Anole Dewlap Color Evolution
Lizards in the genus Anolis represent one of the best-studied groups of reptiles in the world. With over 400 species and high morphological variation, anoles make an excellent study system in which to test evolutionary questions. From a color perspective, they are particularly interesting because they possess a dewlap - an extendable throat fan that is often brightly-colored and used for inter- and intraspecific signaling. Despite decades of study on dewlaps, we still know relatively little about why and how certain colors and patterns have evolved. One hypothesis suggests that the light environment may play a role in dewlap color evolution, as different light conditions may be more or less favorable for communicating via a particular color. I am testing this using the Panamanian slender anole (Anolis apletophallus), a species in which some individuals have mostly white dewlaps and some have mostly orange dewlaps. In collaboration with Alison Davis Rabosky, Christian Cox, Michael Logan, Owen McMillan, and various other researchers at the Smithsonian Tropical Research Institute, I will introduce hundreds of these lizards to experimental islands with varying levels of canopy openness. I will then be able to directly measure the impact of the light environment on the fitness of lizards with different dewlap colors. |
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Evolution of Coral Snake Mimicry
Coral snakes are highly venomous elapids that are often brightly-colored, and they use this coloration as a warning to potential predators that they are dangerous. In addition, many species of relatively harmless snakes have evolved similar color patterns, which allow them to deceptively signal to potential predators that they, too, are dangerous. Although the benefits of looking like a coral snake may seem obvious, biologists have largely overlooked a critical component of coral snake mimicry: behavioral mimicry. Coral snakes and their mimics engage in a number of characteristic displays when threatened, such as thrashing, burying their heads, and waving their tails. Together with Alison Davis Rabosky, Talia Moore, and collaborators from the Department of Engineering at the University of Michigan, I am working to build snake robots that can behave like coral snakes. I will produce these robots in a variety of colors and deploy them in tropical forests (where there are many species of coral snakes and mimics). This will allow me to disentangle the roles of color and behavior in the evolution of coral snake mimicry. |
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Color Polymorphism in a Coral Snake Mimicry Complex
Animals in mimicry systems often exhibit striking variation in color patterns, even within a single species. Different combinations of color traits may be produced by selection from predators or from underlying genes, but these effects can be difficult to separate. For my master's thesis, I worked with Christian Cox and Alison Davis Rabosky to study the ground snake (Sonora episcopa), a harmless coral snake mimic that is polymorphic for two mimetic traits (black bands, red stripe) and two non-mimetic traits (black cap, black collar). We combined population genomics and surveys of preserved museum specimens to study trait combinations within and among populations throughout the Great Plains region of the United States. We found that the observed combinations were best explained by both genetic architecture and correlational selection, suggesting that complicated patterns of color combinations across a landscape can be driven by interactions between multiple mechanisms. This research was published in Proceedings of the Royal Society B and can be accessed here: https://doi.org/10.1098/rspb.2021.0003 |