Impact of larval diet on fitness outcomes of Aedes aegypti mosquitoes infected with wAlbB and wMelM

Background Releases of Wolbachia -infected Aedes aegypti are being used to effectively control diseases caused by arboviruses, such as dengue. A well-balanced larval diet is essential for producing Wolbachia -infected mosquitoes with optimal fitness for release. Methods In this study, four diets with varying protein-to-carbohydrate ratios were tested with three Ae. aegypti lines (carrying the w AlbB, w MelM Wolbachia infections or uninfected) to identify optimal diets for larval rearing on the basis of diet allocations ranging from 0.4 to 3.2 mg/larva/day. The diets were selected on the basis of a review of existing literature and are characterized by progressively increasing protein and decreasing carbohydrate content: diet 1 (Pd) was based on plant-based protein (low protein and high carbohydrate), diet 2 (Kd) was based on animal-based protein (moderate protein and high carbohydrate), diet 3 (Fd) involved Hikari fish food (high protein and moderate carbohydrate), and diet 4 (IAEA) followed a widely used very-high-protein and low-carbohydrate diet developed by the International Atomic Energy Agency (IAEA). The optimal concentration for each diet was determined using a fitness index that incorporated pupation success, fecundity, hatch proportion and development time. Results The optimal dietary allocations for diets 1–4 were 1.6, 1.2, 1.2 and 0.8 mg/larva/day, respectively, regardless of Wolbachia status. There was a consistent significant positive relationship between female wing length and fecundity in w AlbB ( r 2 = 0.881), w MelM ( r 2 = 0.329), and uninfected ( r 2 = 0.886) mosquitoes. Diet 3 (Fd) at optimal food allocation reduced a fitness cost commonly associated with the w AlbB line compared with the uninfected line when provided at the optimal concentration. The w MelM line showed a persistently low fecundity regardless of diet and concentration. Conclusions These findings highlight the importance of an appropriate larval diet and dietary allocations in optimizing mosquito fitness for Wolbachia -based vector control programs. Further research into dietary composition, gut microbial interactions and Wolbachia associations could refine larval nutrition strategies, enhancing the effectiveness of mass-rearing for release programs.