A Lizard Predation Experiment Demonstrates Batesian Ant Mimicry in Camponotus lateralis

The Mediterranean ant species Camponotus lateralis is often associated with the unpalatable Crematogaster scutellaris complex, and workers of both taxa commonly share trails. The recent discovery of three color morphs in Ca. lateralis, each resembling sympatric Crematogaster model species, provides context for the hypothesis of Batesian mimicry. Here, a feeding experiment was conducted using 25 Italian wall lizards (Podarcis siculus) as real predators. Our experiment tested four predictions regarding the predation risk for inaccurate mimics, accurate mimics, and models. Each lizard individual was confronted either with Cr. scutellaris or Cr. schmidti models, which both have a reddish head and a blackish gaster but differ by the former having a blackish and the latter a reddish mesosoma. Minor ant workers of Ca. lateralis, mimicking each one of these models, were used as inaccurate and accurate mimics. Also, the jet-black Ca. piceus was used as an inaccurate mimic. Lizards ingested 1.8 times more Camponotus than Crematogaster ants. Without model experience, lizards ingested 1.9 times more inaccurate and accurate mimics than after gaining such experience. Predation on model ants increased 1.4-fold when models were spatially closer to the mimics, a result consistent with the expectation that positive experience with mimics weakens avoidance of models through stimulus generalization. Although lizards ingested similar numbers of inaccurate and accurate mimics, 2 months after model experience, they chose the inaccurate mimic first in 83% of cases. We conclude that resemblance and spatial proximity to the model decrease predation risk for the mimic and increase predation risk for the model. We suggest that predation drives the evolution of aposematism in Crematogaster and Batesian color mimicry in Ca. lateralis. Conversely, myrmecophagy could have contributed to the evolution of cognitive abilities in lizards.