Mimics and models of New World snakes

Images 
False tree coral (Rhinobothryum bovallii)

Venomous or not? In fact, this is not a coral snake, but a false tree coral (Rhinobothryum bovallii). Photo by Greg Lasley licensed under CC BY-NC 4.0.

Not all snakes need venom to scare predators away. A large group of harmless snakes simply mimics the appearance of noxious species as a means of deterring their enemies through deceit. In this paper, researchers studied distributional, phenotypic and phylogenetic data across all New World snakes, and investigated how shifts to mimetic coloration relate to the evolution of venomous coral snakes. Using GBIF-mediated occurrences, the researchers constructed geographic ranges of more than 1,000 species, and found that coral snakes are a strong predictor of the abundance of mimics. However, the number of observed mimetic species is much higher than expected. Phylogenetic analysis revealed at least 19 independent origins of mimetic coloration, and not surprisingly these all appear after the arrival of coral snakes. Interestingly, the researchers also find evidence of widespread loss of mimetic coloration, rejecting previous suggestions that mimicry is evolutionarily irreversible.

Citation information 

Davis Rabosky AR, Cox CL, Rabosky DL, Title PO, Holmes IA, Feldman A and McGuire JA (2016) Coral snakes predict the evolution of mimicry across New World snakes. Nature Communications. Springer Nature 7: 11484. Available at: https://doi.org/10.1038/ncomms11484.