A quantitative analysis of Micrurus coral snakes reveals unexpected variation in stereotyped anti-predator displays within a mimicry system
Warning signals in chemically defended organisms are critical components of predator-prey interactions, often requiring multiple coordinated display components for effective communication. When threatened by a predator, venomous coral snakes (genus Micrurus) display a vigorous, non-locomotory thrashing behavior that has been only qualitatively described. Given the high-contrast and colorful banding patterns of these snakes, this thrashing display is hypothesized to be a key component of a complex aposematic signal under strong stabilizing selection across species in a mimicry system. By experimentally testing snake response across simulated predator cues, we analyzed variation in the presence and expression of a thrashing display across five species of South American coral snakes. Although the major features of the thrash display were conserved across species, we found significant variation in the propensity to perform a display, the duration of thrashing, and the curvature of snake bodies that was mediated by predator cue type, snake body size, and species identity. We also found an interaction between curve magnitude and body location that clearly shows which parts of the display vary most across individuals and species. Our results suggest that contrary to the assumption that all species and individuals perform the same display, a high degree of variation persists in thrashing behavior exhibited by Micrurus coral snakes despite presumably strong selection to converge on a common signal. This quantitative behavioral characterization presents a new framework for analyzing the non-locomotory motions displayed by snakes in a broader ecological context, especially for signaling systems with complex interaction across multiple modalities.
BibTex:
@article{Moore2020a,
author = {Moore, Talia Y. and Danforth, Shannon M. and Larson, Joanna G. and {Davis Rabosky}, Alison R.},
title = {{A quantitative analysis of \textit{Micrurus} coral snakes reveals unexpected variation in stereotyped anti-predator displays within a mimicry system}},
doi = {https://doi.org/10.1093/iob/obaa006},
year = {2020},
journal = {Integrative Organismal Biology}
}