Aedes aegypti midgut microbiota establishment in adult females is regulated by Juvenile Hormone to enhance fecundity and fitness.

AbstractUnderstanding the physiological phenomena involved in female mosquitoes' preparation for a blood meal, including the effects of mating, is crucial for enhancing vector-control strategies against mosquito-borne diseases. At the same time, the mosquitoes’vector capacity can be impacted by fecundity and longevity, making important the study of the factors that can influence these. Our findings reveal that mating and Juvenile Hormone induce midgut growth in Aedes aegypti mosquitoes. Additionally, we observed the gradual establishment of a native bacterial population in the mosquito midgut due to JH-dependent suppression of the immune response. Mated mosquitoes and those treated with JH exhibited lower expression levels of Anti-Microbial Peptides. The increased presence of bacteria in the midgut stimulated epithelial cell turnover, indicating the dynamic response of the epithelium to the microbiota. Here we demonstrate how mating and JH levels can influence organ size and immunity in the mosquito midgut. JH-induced expansion of the microbiota downregulated certain antimicrobial peptides in Ae. aegypti, leading to increased egg counts and longer lifespans. Overall, these findings provide evidence of a cross-talk between JH response, gut epithelial tissue, cell cycle regulation, and the mechanisms governing the trade-offs between nutrition, immunity, and reproduction at the cellular level in the mosquito gut.