Pollen-borne microbiome influences the host fitness and endosymbiont in the solitary bee, Megachile rotundata

The alfalfa leaf cutting bee, Megachile rotundata F. is an important field crop pollinator. The females provision its offspring with pollen from different plant species. Pollen has a diverse community of microbes that are symbiotically associated with bees and contribute to their health and survival. Additionally, Lactobacillus clade is the most abundant microbe in the gut helping bees to digest pollen and has demonstrated resistance to a broad range of antibiotics. Despite the apparent importance of the microbial community, evidence concerning the direct and indirect affects of provision microbes on physiology, growth rate, and survival is lacking in M. rotundata. To test this hypothesis, we reared larva on the following provision treatments: pollen provision with antibiotics, sterile pollen provision, sterile pollen provision + Lactobacillus micheneri, natural pollen provision + Lactobacillus micheneri, and natural pollen provision (control). Gamma irradiation was used to sterilize the natural pollen provision. Individuals reared on all diets didn’t show any significant effects on the and mass of larvae, prepupae when compared to natural control. Higher moraltity was obswrved when larvae were reared on sole Lactobacillus michenerimixed with sterile pollen. Moreover, we used 16s gene sequencing study showed dominance of endosymbiont Sodalis when fed on natural pollen provision with additional Lactobacillus micheneri In the future, this study will improve the understanding of microbiome symbiotic relations with bee health and nutrition.