Environmental heterogeneity across an urban gradient influences detritus and nutrients within artificial containers...

Detrital inputs from the surrounding terrestrial environment provide essential nutrients that sustain mosquito populations in aquatic containers. The larvae of Aedes aegypti (L.), an anthropophilic invasive vector species, often develop in artificial habitats in urban areas but little is known about how that environment shapes their life history or phenotypic traits. We hypothesized that container detritus, nutrients, and larval interspecific competition with the endemic mosquito, Aedes mediovittatus (Coquillett), would vary along an urban gradient in the San Juan Metropolitan Area in Puerto Rico. We also hypothesized that fine-scale variations within a 200 m buffer of the container environment would alter Ae. aegypti larval nutrients, density, and biomass. We sampled mosquito larvae, container detritus, and suspended particulate organic matter in 44 locations and characterized the surrounding environment in terms of land cover, land use, and vegetation α diversity. We show that container detritus and nutrients are influenced by fine-scale environmental variations environment, affecting Ae. aegypti and Ae. mediovittatus larvae phenotypic traits and nutrient composition. Aedes aegypti was the dominant species in all samples across the urban gradient. We found a negative relationship between Ae. mediovittatus larval % carbon and vegetation cover in the surrounding environment, and a negative correlation between this species' larval C:N and suspended particulate organic matter C:N. These findings suggest a potential disadvantage in nutrient allocation that could affect its competitive ability in urban areas. We found smaller and less nitrogen enriched (δ¹⁵N) Ae. aegypti in containers surrounded by higher impervious cover. The implications of these findings on potential vector disease risk across urban gradients are discussed.