Tactile stimuli induce deimatic antipredator displays in ringneck snakes

Abstract

AbstractAdaptations for predator defense are often complex traits with integrated display components spanning multiple signaling modalities. For antipredator coloration like deimatic or startle coloration, behavioral variation controlling dynamic color displays is an important but poorly understood component of the predator defense in most taxa. We studied antipredator behavior in North American ringneck snakes (Diadophis punctatus), which possess a brightly colored (red to yellow) ventral surface of the body and the tail compared to the mostly gray dorsal coloration. We sought to (a) characterize intraspecific variation in antipredator behaviors in ringneck snakes and (b) test which stimuli can induce antipredator displays. First, we assessed antipredator displays in the field and during routine handling during data collection by comparing categorical classifications of all displayed behavior across 25 individuals. Second, we performed experimental assays with tactile and visual stimuli to determine the cues that can elicit an antipredator display in ringneck snakes. We found that antipredator displays include ventral displays and tail‐coiling and that these components were induced by tactile cues in the field and the lab, but not visual cues. Our work is the first to show that a snake species with bright ventral coloration uses this behavior in response to tactile cues from a potential predator, but only in response to relatively strong stimuli (i.e., handling). This experimental evidence that tactile stimuli can induce a behavior revealing bright ventral coloration highlights the importance of correlated evolution of antipredator coloration and behavior.