Evolution of Antipredator Coloration
Color has long been the focus of research on phenotypic diversity and trait evolution because of clear fitness benefits for reproduction (sexual selection) and survival (crypsis, aposematism, mimicry). Nonetheless, little is known about how selection and other evolutionary forces promote and maintain variation in color. My research seeks to understand 1) how selection acts upon color in mimicry complexes, 2) the temporal dynamics of color evolution, 3) the genomic basis of color polymorphism and selective dynamics in color pattern genes. We have focused on the evolution of antipredator coloration in squamate reptiles, including the ground snake (Sonora semiannulata), a coral snake mimic with four distinct color morphs. Our broad-scale comparative work has revealed that while there is a tight temporal and spatial match between coral snakes and their putative mimics, temporally dynamic color evolution as well as the greater abundance and species richness of mimics compared to coral snakes transgresses the predictions of classical mimicry theory (Cox et al. 2012 Systematics and Biodiversity 10:93-108; Davis Rabosky et al. 2016 Nature Communications 7:11484). Our research with ground snakes has revealed that spatially and temporally variable selection favors rare color morphs in this mimicry system (Cox and Davis Rabosky 2013 American Naturalist 182:E40-E57), and this has led to a chaotic taxonomy (Cox et al. 2018 Journal of Natural History 52:13-16). In a dramatic departure from the predictions of mimicry theory, there is no evidence that supergenes control mimetic coloration in a coral snake mimic, but rather that their coloration is controlled by two unlinked genes (Davis Rabosky et al. 2016 Evolution 70:944-953).Current research in my laboratory seeks to understand 1) the genomic basis of color patterns in polymorphic organisms, 2) ecological drivers of antipredator coloration, and 3) determining the genomic basis of mimetic traits and dynamics of selection on mimetic loci .