Recent and rapid diversification of the small carpenter bees in eastern North America

Bees fulfil a critical ecological role as pollinators, significantly contributing to the reproductive success of myriad angiosperm species. Although increasingly appreciated for their agricultural contributions, relatively little is yet known about the natural history of the vast majority of the more than 20 000 wild bee species worldwide. The small carpenter bee genus Ceratina occurs globally, and is represented in North America by its most recently diverged subgenera, Ceratinula and Zadontomerus. Recent genetic analysis of eastern Ceratina (Zadontomerus) supports the existence of five closely related, yet genetically distinct species living in sympatry. This phylogeographical study employs molecular barcoding of the most comprehensive specimen collection yet assembled to confirm the identities of these recently diverged eastern North American Ceratina (Zadontomerus) species. Delineation of extant population structure, evolutionary history and known range of this emerging model native pollinator are greatly improved by this study. We consider ecological and behavioural factors potentially contributing to the maintenance of genetic identity among these sympatric species.