Convergence and divergence in anti-predator displays: a novel approach to quantitative behavioural comparison in snakes

Abstract

Animals in nature use many strategies to evade or deter their predators. Within venomous snake mimicry, stereotyped anti-predator behaviours are hypothesized to be effective warning signals under strong selection for independent convergence across species. However, no studies have systematically quantified snake anti-predator displays across taxonomically broad clades to examine how these behaviours evolve within a comparative methods framework. Here we describe a new high-throughput approach for collecting and quantifying anti-predator displays in snakes that demonstrates both low observer bias and infinite extension. Then, we show this method’s utility by comparing 20 species spanning six taxonomic families from Peru. We found that a simple experimental set-up varying simulated predator cues was successful in eliciting displays across species and that high-speed videography captured a great diversity of anti-predator responses. Although display components show complicated patterns of covariance, we found support for behavioural convergence in anti-predator displays among elapid coral snakes and their distantly related mimics. Our approach provides new analytical opportunities for both behaviour and kinematics, especially macroevolutionary analyses across clades with similar difficulty in observing or comparing trait diversity.

Tactile stimuli induce deimatic antipredator displays in ringneck snakes

“…These linkages between color and multiple behavioral traits suggest that all deimatic traits could be parts of co-adapted character complexes (Brodie III, 1992;Cheverud, 1996;Lande, 1984;Vidal-García et al, 2020). Future research should (a) assess the determinants of deimatic behaviors in other snake species with concealed coloration, (b) document behaviors correlated with other types of antipredator coloration in poorly studied groups (Creer, 2005;Davis Rabosky et al, 2021;Moore et al, 2020), and (c) determine the comparative pattern of bright ventral coloration across the snake tree of life. The goal of this research would be to reveal the evolutionary forces underlying the evolution of color diversity in snakes.…”

“…Many defensive behaviors are deployed in response to a stimulus, which can include signals from predators or other dangerous situations (Blanchard et al, 1994). The predatory stimulus can be of a tactile (Brodie et al, 1991;Davis Rabosky et al, 2021;Mukherjee & Trimmer, 2020;Roth & Johnson, 2004), olfactory (Peacock, 1998), auditory (Curlis et al, 2016), or visual nature (Davis Rabosky et al, 2021;Herzog et al, 1989;Moore et al, 2020). The behavioral response that is invoked in response to the predatory stimuli is often potentiated by the intensity of the stimulus (Herzog et al, 1989;Roth & Johnson, 2004) and body temperature in ectotherms (Brodie et al, 1991).…”

Virtual Expeditions Facilitated by Open Source Solutions Broaden Student Participation in Natural History Research

“…In contrast, interpretation during in-person expeditions often relies on the individual's expertise and rapid interpretation ( McBride et al 2012 ). The Virtual Expeditions have resulted in several important natural history findings, including peer-reviewed literature with student authors and contributions to local and state agency management plans ( Davis Rabosky and Moore et al 2021 ). Each case study here has supported the analyses of thousands of photo/video observations, representing a portion, but not all, of the samples contained within the associated field expedition.…”

“…In the materials provided to students, objective and discrete categories for identification can reduce error (e.g., presented in a drop-down menu format or multiple choice). If starting this program anew, a pilot program with a smaller group can be helpful, including both novices and experts, to develop the methodology (see, e.g., Davis Rabosky et al 2021 ). It is important that the categorization method rely on objective features as much as possible.…”

Description of the antipredatory head-wobble behaviour in Chilean rear-fanged snakes Tachymenis peruviana Wiegmann, 1835 and Tachymenis chilensis coronellina Werner, 1898 (Serpentes, Dipsadidae)

“…Snakes exhibit a wide repertory of antipredatory behaviours including fast and secretive movements, cryptic camouflage, aposematic displays, mimicry and death feigning (e.g., Mutoh 1983;Herzog and Burghardt 1986;Gerald 2008;Gregory 2008Gregory , 2016Santos et al 2018;Zañartu and Urra 2020;Davis et al 2021). Notably, head-wobble is a poorly reported behaviour exhibited by some rear-fanged snakes, which involves an oscillating movement of the head and neck while the rest of the body remains motionless (Ryerson 2017).…”