Evolutionary arms race in ant-ant mimicry: Camponotus lateralis lags behind in mimicking color patterns and sizes of regional Crematogaster models

Abstract

Abstract Over a century ago, biologists proposed the Mediterranean ant Camponotus lateralis mimicked the coloration of the common and unpalatable ant Crematogaster scutellaris . A more recent hypothesis suggested that Ca. lateralis also mimicked the color of two additional models, Cr. schmidti and Cr. ionia , in their respective range. This study aims to test the hypothesis using red–green–blue values of 573 model and 957 mimic individuals and whether also size is affected by mimicry. The results support the regional-mimicry hypothesis: Camponotus lateralis is phenotypically more similar to syn- than to allotopic models. However, regional mimics evolutionarily lag behind the stronger radiated color and body-size traits of the models. Camponotus lateralis mimicked the coloration of the West Mediterranean species Cr. scutellaris least accurately, pointing to the possibility that the East Mediterranean species Cr. schmidti and Cr. ionia are the primary models, and Cr. scutellaris entered the system at a later stage. Fascinatingly, the example of Ca. lateralis is one of several analogous cases of convergent color evolution in camponotine ants that mimic Crematogaster models of different coloration. The unusually strong discriminant power of color variables in Crematogaster models—only partially replicated by their mimics—indicates a chase-away dynamic in response to Batesian mimicry.