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

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 pattern - but 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. [ABSTRACT FROM AUTHOR]