Assessing Müllerian mimicry in North American bumble bees using human perception.

Despite the broad recognition of mimicry among bumble bees, distinct North American mimicry rings have yet to be defined, due in part to the prevalence of intermediate and imperfect mimics in this region. Here we employ a generalization approach using human perception to categorize mimicry rings among North American bumble bees. We then map species distributions on North American ecoregions to visually test for geographic concordance among similarly-colored species. Our analyses suggest that there are five mimicry rings in the North American bumble bee mimicry complex, and one broadly distributed group of mixed and intermediate color forms. We describe the Black Mimicry Ring, Black-cloaked Mimicry Ring, Eastern Yellow Mimicry Ring, Red Mimicry Ring, and Western Yellow Mimicry Ring as well as the mixed group. We then test these hypothesized mimicry rings by examining other insects that participate in these mimicry rings. Describing these mimicry rings is a vital step that will enable future analyses of imperfect mimicry, intermediate mimicry, and additional analyses of other insects that mimic bumble bees.