(1st Place) Establishment and health impacts of floral and intraspecific microbes in bees

Bees interact with and in some cases benefit from a diverse community of microbes, which can be obtained through intraspecific interactions or the environment. Due to differences in sociality, bee species vary in their main route of microbial acquisition and their dependence on microbes. Despite the observation that intraspecific transmission of microbes is imperfect and environmental microbes are nearly ubiquitous in flowers, the potential impacts of intraspecific versus floral microbes on overall pollinator health have not been evaluated. This study uses two model bee species - one social (Bombus impatiens) and one solitary (Osmia lignaria) - to assess the establishment and health impacts of floral and intraspecific microbes. 2x2 factorial experiments were performed on B. impatiens microcolonies and O. lignaria females to selectively introduce intraspecific microbes and/or floral microbes. Survivorship and reproduction were measured to assess bee health and fitness, and DNA extractions and amplicon sequencing were performed on bee guts to evaluate microbial establishment. The results of this study will inform how microbes from different acquisition routes establish in the host, shape the gut microbiome, and affect host health. Since many macroorganisms encounter both intraspecific and environmental microbes, this study provides a framework for similar work in other organisms.