Mimicry profiles are affected by human-induced habitat changes

Mimicry theory predicts that mimics in a Batesian mimicry complex evolve to resemble models closely, and that there is a limit on the numbers of mimics relative to models. For hoverflies (Diptera: Syrphidae), supposed mimics of social wasps (Hymenoptera: Vespidae), neither of these is true; many mimics are imperfect and in the UK and Europe they outnumber their models manifold. We hypothesized that the high abundance of mimics relative to models in the UK mall be the result not just of mimic-model dynamics, but of habitat changes caused by humans. Most of the larvae of poor mimics are aphidophagous, and changes from ancient forest to agricultural and/or urban habitats may have vastly augmented aphid numbers. Using new and literature data, we compared mimicry profiles of habitats differing in their degree of habitat disturbance. In both cases, more highly disturbed habitats had proportionally more poor mimics and fewer high-fidelity mimics than less disturbed habitats. This supports the hypothesis that habitat change has an effect on model to mimic ratios.