The role of larval density and food availability in life-history traits of Aedes aegypti mosquitoes

Fluctuations in food availability and larval density play pivotal roles in shaping the characteristics of Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) mosquito populations through intraspecific competition. Competition for limited resources drives density-dependent effects, influencing survival rates, time to pupation, and the size and lifespan of adult mosquitoes. Our study aimed to investigate the effects of competition, driven by variations in food and larval density, on the development and life cycle of A. aegypti. We examined the outcomes of nine distinct combinations of aquatic larval density and resource availability—measured in terms of per capita food and individual space—on key developmental metrics, including larval mortality, time to pupation, adult size, and lifespan. Our findings indicate that food availability had a more pronounced effect on larval mortality and development time than did larval density. Notably, intermediate levels of food availability and density were more conducive to higher survival rates and larger adult sizes than either low-density conditions or an excess of resources. The density-dependent effects, particularly, had a significant impact on adult size, often outweighing the influence of food availability. Furthermore, alleviation from competition among larvae emerged as a more critical factor in extending adult lifespan than the direct influence of resources or density alone. In conditions where food resources were scarce or competition was intense, larvae experienced prolonged development times and a higher likelihood of failing to pupate, resulting in smaller adults with reduced lifespans. These combined stressors significantly diminish the fitness (i.e., mortality and developmental parameters) of A. aegypti, highlighting the complex interplay between resource availability and intraspecific competition in determining the population dynamics of this species.