Prevalence and patterns of bacterial endosymbionts in solitary bees

Solitary bees play an important role as pollinators of crops and native flora. Certain species are utilized for orchard pollination, making them desirable for commercial use in North America. Bees within the genera Megachile and Osmia are sold and shipped nationwide to supply these commercial demands. This flux of bees also means movement of their microbiota, including bacterial endosymbionts capable of manipulating host reproduction. To test for presence of these bacteria in commercially available species of orchard pollinators in the United States, I used diagnostic PCR to screen for bacterial taxa previously documented to cause reproductive anomalies. I also screened wild-caught solitary bees from various landscapes in Lexington (KY) to compare with the commercial bees. I supplemented my screening with 454-pyrosequencing on two commercial and two local species. Consistent with literature, the endosymbiont Wolbachia was abundant in these bees (predominantly within Halictidae). I also found two endosymbiotic bacteria that were previously undetected in bees; Sodalis in the commercial species Osmia aglaia and Arsenophonus in the local species Lasioglossum pilosum. Further diagnostic screening demonstrated that Sodalis was present at a fixed frequency in O. aglaia, whereas Arsenophonus was present at a very low frequency in L. pilosum. These frequency differences may allude to their potential roles in their hosts. My results show that other endosymbionts capable of reproductive manipulation, besides Wolbachia, are present in bees. Future research should investigate the effects of these endosymbionts on solitary bee fitness and ecology.