Predator response to the coloured eyespots and defensive posture of Colombian four-eyed frogs

Abstract

Deimatic displays, where sudden changes in prey appearance elicit aversive predator reactions, have been suggested to occur in many taxa. These (often only putative) displays frequently involve different components that may also serve antipredator functions via other mechanisms (e.g., mimicry, warning signalling, body inflation). The Colombian four‐eyed frog, Pleurodema brachyops, has been suggested to gain protection against predation through putative deimatic displays where they inflate and elevate the posterior part of their body revealing eye‐like colour markings. We exposed stationary artificial frogs to wild predators to test whether the two components (eyespot/colour markings, defensive posture) of their putative deimatic display, and their combination, provide protection from predation without the sudden change in appearance. We did not detect any obvious additive effect of defensive posture and eyespots/colour markings on predation risk, but found a marginally significant trend for model frogs in the resting posture to be less attacked when displaying eyespots/colour markings than when they were not, suggesting that the presence of colour markings/eyespots may provide some protection on its own. Additionally, we found that models in a resting posture were overall more frequently attacked on the head than models in a defensive posture, indicating that a defensive posture alone could help redirect predator attacks to non‐vital parts of the body. The trends found in our study suggest that the different components of P. brachyops' coloration may serve different functions during a deimatic display, but further research is needed to elucidate the role of each component when accompanied by sudden prey movement.

Predator selection on multicomponent warning signals in an aposematic moth

“…For example, many warning signals are multimodal, consisting of visual signals, sounds, odors, and chemical secretions that may have interactive effects ( Rowe and Halpin 2013 ). Another potential factor influencing warning signal efficacy is prey shape or posture that might be particularly important when visual signals are combined with deimatic behavior ( Hernández-Palma et al 2023 ; Riley et al 2023 ). Even within one modality, there can be multicomponent signals that consist of different elements, such as visual warning signals that are composed of distinct colors, shapes, and patterns on different body regions ( Rowe 1999 ; Bradbury and Vehrencamp 2011 ).…”