Contrasted impacts of commercial diets and rearing water on <i>Aedes aegypti</i> fitness and microbiota

Mosquito rearing optimization in laboratory conditions is crucial for both vector research and control. Although the addition of nutrients is important for <i>Aedes aegypti</i> development from immature stages to adult mosquitoes, little is known about the nutrient composition of commercial diets used for mosquito rearing and their influence on <i>Ae. aegypti</i> life traits. Here, we evaluated the influence of four commercial diets commonly used to rear <i>Ae. aegypti</i> in the laboratory on its fitness, lifespan, and microbiota. We also compared the effect of these diets on this mosquito when combined with two different rearing waters (laboratory versus field-collected waters). Our investigations demonstrated that higher levels of protein and lipid in commercial diets promote better <i>Ae. aegypti</i> development, lifespan, and size in both water. Metagenomic analysis revealed specific modulations of adult microbiota composition according to both diet and rearing water. <i>Chryseobacterium</i> dominated the microbiota of female mosquitoes reared in laboratory water, except for yeast condition, where a more diverse microbiota was observed. When reared in larval site water, the microbiota diversity was overall higher despite diet addition, except for fish food, which promoted <i>Sphingobacterium</i> dominance. Given the pivotal influence of diet addition during the larval stage on <i>Ae. aegypti</i> microbiota and life traits, rearing conditions should be carefully chosen according to the goals of the research (i.e., vectorial capacity estimations) or vector control intervention.IMPORTANCE<i>Aedes aegypti</i> is the main vector of arbovirus, such as dengue, yellow fever, and chikungunya viruses. Vector research and control are primarily carried out in laboratories, with larval stage rearing conducted using commercial diet. If many nutrients are essential for <i>Ae. aegypti</i> development, gaining insight into the influence of these diets and their nutrient levels is important to promote optimized rearing worldwide. In this study, our results indicated a significant impact of commercial diet on <i>Ae. aegypti</i> development, lifespan, size, and microbiota related to contrasted protein, lipid, and carbohydrate levels in these diets. This study will help people working with <i>Ae. aegypti</i> raise awareness in staff working with <i>Ae. aegypti</i> to select optimized diets for their specific purpose.