Mullerian Mimicry among Bees and Wasps: a Review of Current Knowledge and Future Avenues of Research

Many bees and stinging wasps, or aculeates, exhibit striking colour patterns or conspicuous coloration, such as black and yellow stripes. Such coloration is often interpreted as an aposematic signal advertising aculeate defences: the venomous sting. Aposematism can lead to Mullerian mimicry, the convergence of signals among different species unpalatable to predators. Mullerian mimicry has been extensively studied, notably on Neotropical butterflies and poison frogs. However, although a very high number of aculeate species harbour putative aposematic signals, aculeates are under-represented in mimicry studies. Here, we review the literature on mimicry rings that include bee and stinging wasp species. We report over a hundred described mimicry rings, involving a thousand species that belong to 19 aculeate families. These mimicry rings are found all throughout the world. Most importantly, we identify remaining knowledge gaps and unanswered questions related to the study of Mullerian mimicry in aculeates. Some of these questions are specific to aculeate models, such as the impact of sociality and of sexual dimorphism in defence levels on mimicry dynamics. Our review shows that aculeates may be one of the most diverse groups of organisms engaging in Mullerian mimicry and that the diversity of aculeate Mullerian mimetic interactions is currently under-explored. Thus, aculeates represent a new and major model system to study the evolution of Mullerian mimicry. Finally, aculeates are important pollinators and the global decline of pollinating insects raises considerable concern. In this context, a better understanding of the impact of Mullerian mimicry on aculeate communities may help design strategies for pollinator conservation, thereby providing future directions for evolutionary research.