D3065: Bacterial diversity in wild bee pollen provisions

Microbes are an invisible factor that is intertwined in pollination interactions. Transmission of
microorganisms occurs by physical contact between pollinators and flowers, a process known as
environmental transmission. The adult bee-gut microbiota of non-social apids and other wild bees is
heavily influenced by this process. However, this is not the first time in the bee’s life cycle where they
encounter microbes. Before reaching the adult stage, the nest environment is the first arena where
bees, both social and solitary, are exposed to microbes. Different microorganisms may be transported
to the nest when female bees build and provision brood cells. Thus, we examined bacterial diversity using shotgun metagenomics data for 11 wild bee species. We found great frequency of acidic bacteria in the pollen provisions examined. We discuss the implications of our findings, especially how fermentation of the pollen provision may be induced by the bacterial activity before or while the larvae feed on it.