Microbiome profiles on Drosophila melanogater. Studies of microbiome effect on oogenesis.

Microbiome has been identified as an environmental factor influencing Drosophila reproduction. However, it needs to be made clear how microbes govern germline development. Here, we present that microbes deposited by laboratory-reared flies enhance oogenesis by proliferating germline stem cells, resulting in accelerated egg maturation. Our genetic approach revealed that microbes activate ecdysone and juvenile hormone pathways at distinct ovarian stages but not insulin pathways, known to be induced by nutrition. Our results suggest that the microbiome utilizes intrinsic hormonal pathways and modulates animal fitness for host reproduction by compensating for poor nutrition conditions.