Mapping the evolution of accurate Batesian mimicry of social wasps in hoverflies

• DOI: 10.1111/evo.14336
• Publication Date: 2021-08-31T17:43:40Z
• Authors: Alice Leavey; Christopher H. Ta...; Matthew R. E. Sym...; Francis Gilbert; Tom Reader
• Keywords: 0301 basic medicine; Biological Mimicry; Wasps; Batesian mimicry; distance transform; 03 medical and health sciences; image analysis; evolution; Genetics; Animals; Syrphidae; General Agricultural and Biological Sciences; similarity; Ecology, Evolution, Behavior and Systematics

Hoverflies (Diptera: Syrphidae) provide an excellent opportunity to study the evolution of Batesian mimicry, where defenseless prey avoid predation by evolving to resemble defended "model" species. Although some hoverflies beautifully resemble their hymenopteran models, others seem to be poor mimics or are apparently nonmimetic. The reasons for this variation are still enigmatic despite decades of research. Here, we address this issue by mapping social-wasp mimicry across the phylogeny of Holarctic hoverflies. Using the "distance transform" technique, we calculate an objective measure of the abdominal pattern similarity between 167 hoverfly species and a widespread putative model, the social wasp, Vespula germanica. We find that good wasp mimicry has evolved several times, and may have also been lost, leading to the presence of nonmimics deep within clades of good mimics. Body size was positively correlated with similarity to the model, supporting previous findings that smaller species are often poorer mimics. Additionally, univoltine species were less accurate wasp mimics than multivoltine and bivoltine species. Hence, variation in the accuracy of Batesian mimics may reflect variation in the opportunity for selection caused by differences in prey value or signal perception (influenced by body size) and phenology or generation time (influenced by voltinism).