Variation in diet and microbial exposure shape the performance of the Asian tiger mosquito, Aedes albopictus

Along their life cycle, mosquitoes colonize different ecological niches with various microorganisms and diet sources that likely modulate their performance (i.e. a set of mosquito fitness-related traits). However, which ecological parameters and how their variations modulate mosquito performance is not completely understood. In this study, we used Ae. albopictus surface-sterilized eggs re-associated or not to conventional bacterial microbiota upon a range of diet concentrations and addressed the impact of microbial inoculum and diet concentration variation on several mosquito performance traits. Results showed that mosquito juvenile survival depends on the interaction between bacterial inoculum load and diet concentration in the breeding water. Exposure to bacteria in rearing water shorten larval development time although it impacted larvae survival in an inoculum and diet concentration-dependent manner. Bacterial composition of larval rearing water was mainly structured by the bacterial inoculum concentration, with some Operational Taxonomic Units abundances correlating with larval traits. Ae. albopictus survival, development and bacterial community patterns upon gradients of diet and bacterial inoculum illustrated the complex impact of diet-microbiota interaction on mosquito performance. These findings argue the importance of deciphering host-microbe-environment interactions and open promising perspectives to improve Ae. albopictus control measures in the field. IMPORTANCEMicrobiota is increasingly recognized as a driving force of metazoan biology, impacting diverse traits including nutrition, behaviour or reproduction. The microbial impact on host nutrition is among the most studied host-microbe interactions although it remains poorly understood in arthropod vectors like mosquitoes. Here, we manipulated mosquito microbiota using gnotobiology to decipher the impact of bacteria and diet on the Asian tiger mosquito, Ae. albopictus. These results are key to understand the link between diet and bacteria concentration on juvenile mosquitoes as well as carry-over effects in adults. They unveil some specific aspects of mosquito-bacteria interactions while opening interesting avenues for vector management of this vector of arboviruses.