A bee or not a bee: an experimental test of acoustic mimicry by hoverflies

The degree of similarity between Batesian mimics and their models varies widely and occurs across a range of sensory modalities. We use 3 complementary experimental paradigms to investigate acoustic mimicry in hoverflies (Diptera: Syrphidae), which mimic stinging Hymenoptera. First, we analyze sounds made by 13 hoverfly species and 9 Hymenoptera species with and without simulated predation (“alarm” and “flight” sounds, respectively). We demonstrate that the bumblebees Bombus terrestris, Bombus hortorum, and Bombus lucorum and the hoverfly Cheilosia illustrata exhibit alarm sounds that are significantly different to their respective flight sounds, and indistinguishable between species. We then demonstrate that the B. terrestris alarm sound reduces predation on artificial prey by wild birds, but that the hoverfly mimic alarm sound does not. Finally, we trained chicks to avoid distasteful food in the presence of different acoustic stimuli. Overall, the chicks showed no difference in respon...