Teasing apart crypsis and aposematism - evidence that disruptive coloration reduces predation on a noxious toad

Abstract

Both cryptic and aposematic colour patterns can reduce predation risk to prey. These distinct strategies may not be mutually exclusive, because the impact of prey coloration depends on a predator's sensory system and cognition and on the environmental background. Determining whether prey signals are cryptic or aposematic is a prerequisite for understanding the ecological and evolutionary implications of predator-prey interactions. This study investigates whether coloration and pattern in an exceptionally polymorphic toad, Rhinella alata, from Barro Colorado Island, Panama reduces predation via background matching, disruptive coloration, and/or aposematic signaling. When clay model replicas of R. alata were placed on leaf litter, the model's dorsal patternbut not its colour -affected attack rates by birds. When models were placed on white paper, patterned and un-patterned replicas had similar attack rates by birds. These results indicate that dorsal patterns in R. alata are functionally cryptic and emphasize the potential effectiveness of disruptive coloration in a vertebrate taxon.

Both novelty and conspicuousness influence selection by mammalian predators on the colour pattern ofPlethodon cinereus(Urodela: Plethodontidae)

“…Similar approaches have been used to document predator-mediated selection on colour patterns in diverse taxa, including snakes (Madsen, 1987;Pfennig, Harcombe & Pfennig, 2001), lizards (Husak et al, 2006), mice (Vignieri, Larson & Hoekstra, 2010), frogs (Noonan & Comeault, 2009;Willink et al, 2014;McElroy, 2015), and salamanders (e.g. This clay does not harden under field conditions but retains impressions made by potential predators, thus serving as a record of attack events over several days.…”

“…This clay does not harden under field conditions but retains impressions made by potential predators, thus serving as a record of attack events over several days. Similar approaches have been used to document predator-mediated selection on colour patterns in diverse taxa, including snakes (Madsen, 1987;Pfennig, Harcombe & Pfennig, 2001), lizards (Husak et al, 2006), mice (Vignieri, Larson & Hoekstra, 2010), frogs (Noonan & Comeault, 2009;Willink et al, 2014;McElroy, 2015), and salamanders (e.g. Brodie, 1993;Kuchta, 2005).…”

Peer Review #1 of "Evaluating the utility of camera traps in field studies of predation (v0.1)"

“…Similarly, because different color pattern phenotypes might vary in their conspicuousness to predators, differences in predation rates could be driven by both variation in prey preference and variation in visual detection rate (Stuart et al, 2012;Rojas et al, 2014). Variation in visual detection rate has been shown to be an unlikely explanation for differences in predation rates between color pattern phenotypes in at least a few aposematic taxa (Brodie, 1993;Wüster et al, 2004;Buasso et al, 2006;McElroy, 2016). Nevertheless, restricting analyses to replicas that were actually detected would provide more direct tests of the fitness consequences associated with different prey phenotypes, given that the fitness benefits of aposematic prey should only be realized after predators have detected prey.…”

Multiple Plumage Ornaments as Signals of Intrasexual Communication in Golden‐Winged Warblers

“…To our knowledge, spectral sensitivities for wood warblers have yet to be measured. ;Mcelroy 2015). To model background light environment, we used the D65 light setting: an illumination that represents average standard daylight.…”