ORIGINAL PAPER Experimental evidence for predator learning and Mu ¨ llerian mimicry in Peruvian poison frogs (Ranitomeya, Dendrobatidae) Adam M. M. Stuckert • Pablo J. Venegas • Kyle Summers Received: 23 August 2013 / Accepted: 25 November 2013 Ó Springer Science+Business Media Dordrecht 2013 Abstract The evolution of mimicry is one of the most powerful examples of evolution driven by natural selection; however it is rare in non-insect taxa and thus is understudied. Ranitomeya imitator underwent a ‘mimetic radiation’ and now mimics three congeneric model species (R. fantastica, R. summersi, and two morphs of R. variabilis), creating geographically distinct populations of the species, including four allopatric mimetic morphs. These complexes are thought to represent a case of Mu ¨llerian mimicry, but no prior empirical studies on learned avoidance by predators support this claim. In this study we used young chickens (Gallus domesticus) as naı ¨ve predators to determine if a co- mimetic morph of R. imitator and R. variabilis contribute to reciprocal learned avoidance by predators—a key component of Mu ¨llerian mimicry. Chickens exposed to either stim- ulus species demonstrated reciprocal learned avoidance; thus our results indicate that this complex functions as a Mu ¨llerian mimicry system. This study provides novel empirical evidence supporting predictions of the Mu ¨ llerian mimicry hypothesis in anurans. Our study shows no difference between learned avoidance in stimuli frogs and a ‘novel’ morph of R. imitator that differed in both color and pattern, indicating that learned avoidance by predators may be generalized in this system. Generalized learning provides a plausible mechanism for the maintenance of both polytypic mimicry and the maintenance of intrapopulation phenotypic heterogeneity. Keywords Aposematism  Mu ¨llerian mimicry  Poison frogs  Polytypism  Ranitomeya imitator A. M. M. Stuckert (&)  K. Summers Department of Biology, Howell Science Complex, East Carolina University, 1000 E Fifth St, Greenville, NC 27858, USA e-mail: stuckerta10@students.ecu.edu P. J. Venegas Divisio ´n de Herpetologı ´a, Centro de Ornitologı ´a y Biodiversidad (CORBIDI), Lima, Peru 123 Evol Ecol DOI 10.1007/s10682-013-9685-4