Behaviour 2019
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Batesian mimic more detectable than its model in a poison frog complex
Brendan L McEwen1, Isaac Kinley1, Hannah M. Anderson1, Justin Yeager2, Jonathan N. Pruitt1, James B. Barnett1. 1Department of Psychology, Neuroscience, & Behaviour, McMaster University, Hamilton, ON , Hamilton, Ontario, Canada; 2Biodiversity, Environment, and Health (BIOMAS), Universidad de las Americas, Quito, Pichincha, Ecuador

Aposematism relies on warning signals that advertise chemical defenses and deter predators, and can be parasitized by non-defended mimics that evolve to resemble the signals of their models. Mimicry is often imperfect and mimetic species rarely replicate quantitative trait values of their models. Rather, mimics enter safe phenotypic trait space of resemblance called the ‘Cone of Protection’. We propose mimics could to evolve to be both within this protected trait space and less detectable than the model to predators, a hypothesis which we call ‘Cryptic Imperfection’. Using the poison frog Ameerega bilinguis and its Batesian mimic Allobates zaparo, we computed background contrasts of the species’ aposematic signals and measured detectability in aerial view and in different angles of terrestrial view. We found little support for Cryptic Imperfection as the mimic’s dorsum is of higher contrast than the model, rendering the mimic more detectable to observers. These findings suggest Cryptic Imperfection has not evolved in this system, but rather the mimic in this complex exhibits more exaggerated detectability than its model.