Meeting Abstract
Many species of butterflyfish (Chaetodontidae) exhibit false eyespots (circular regions with dark pigment on the posterior body) but the factors underlying the phylogenetic distribution of this trait remain poorly understood. False eyespots are hypothesized to play a role in predator avoidance and may function to distract predators away from the true eye and head to the posterior of the body to facilitate escape. False eyespots are also thought to play a role in mitigating aggression from conspecifics in some species. Concealment of the eye, most commonly by a vertical stripe, is thought to camouflage the eye from predators, although alternative hypotheses suggest that patterns like eye bars may play a role in reducing glare. Eye coverage commonly co-occurs with false eyespots and the two patterns are hypothesized to complement each other in reducing the conspicuousness of the true eye. We assembled a phylogeny for 95 species of butterflyfish and scored each for the presence/absence of eyespots as well as a suite of other traits related to body coloration and ecology. Comparative analyses in BayesTraits revealed a significant association between false eyespots and eye coverage thus supporting the hypothesis that false eyespots have evolved to distract predators from the true eye. A comparative phylogenetic approach was used to test how color patterns evolve to minimize predation, providing a framework for studying how different factors shape color pattern diversity across fishes.
