Effects of larval density and Wolbachia strains on life-history traits of Aedes aegypti mosquitoes

Abstract Understanding how environmental conditions and symbiotic infections shape mosquito biology is essential for predicting vectorial capacity and optimizing control strategies. Here, we investigated the effects of larval density and Wolbachia infection ( w Mel and w AlbB) on wing morphometry and key life-history traits of Aedes aegypti . Geometric morphometrics revealed that both Wolbachia -infected strains exhibited increased wing length relative to the uninfected population, while asymmetry metrics remained unchanged across treatments. Larval density significantly reduced body size yet did not affect wing symmetry. Survival analyses indicated significant strain-level differences, with w Mel-associated alterations in longevity relative to other groups, whereas larval density exerted no detectable effect on survival. Morphological asymmetry emerged as a consistent predictor of fitness within strains, being associated with increased mortality risk and reduced fecundity. Fecundity was positively correlated with wing length but negatively correlated with asymmetry, highlighting the importance of developmental stability. The effects of Wolbachia strains on its host differed significantly. The w Mel-infected mosquitoes had higher lifespan and reduced fecundity, whereas w AlbB-mosquitoes has reduced lifespan but a slight reduction on reproduction. Taken together, these findings demonstrate that intrinsic (symbiont strain) and extrinsic (larval environment) factors act through partially independent pathways to shape mosquito phenotype and performance, with important implications for Wolbachia -based vector control programs.