Microbiomes impact wild bee development and associate with social role

Despite a growing body of literature characterizing wild bee microbiomes across different bee species and environments, much remains unknown regarding the role that microbes play on wild bee health. To date, the impact of beneficial symbionts and harmful pathogens have been largely examined in Apis melilfera, finding that vertical transmission, social interactions, and the external environment can lead to varying microbial communities that impact bee development, survivorship, growth, and behaviour. We inoculated pollen provisions for Ceratina calcarata small carpenter bees with the probiotic bacteria Apilactobacillus kunkeei to examine the role of beneficial symbionts and diverse microbial communities on bee survivorship. We also characterized the bacterial (16S rRNA), fungal (ITS), and plant (rbcL) composition of bees across three social roles in the nest: mothers, regular daughters, and dwarf eldest daughters. Our results suggest that microbiomes differ across social roles and that microbial symbionts can impact survivorship and mass of developing bees, implying that microbes play an important role in determining bee health and interactions. This research supports the usage of probiotic supplementation for both commercial and conservation practices that can support wild bees amidst environmental stressors.