D3019: Simulated larval control in laboratory mesocosms leads to overcompensation in the yellow fever mosquito, Aedes aegypti

Mortality events can affect populations in counterintuitive ways leading to compensation or overcompensation when density-dependent effects are present. These phenomena occur in a variety of taxa and are important to understand for management of commercial species, conservation of endangered species, and control of arthropod pests. Using a mesocosm experimental design, we simulated different levels of larval control to assess mortality effects in the yellow fever mosquito, Aedes aegypti. We hypothesized that 1) that adult production will be highest at middle densities, 2) that adult body size will have an inverse relationship with larval density, and 3) that survivorship will have an inverse relationship with larval density. Various larvae densities (100, 200, 500, 1000, and 2000 larvae/L) were placed in 500 mL water and assessed for number of adults produced, female adult body size measured via wing length, development time, and percent survival. A segmented liner analysis approach was used to determine the response of the mosquitoes to the mortality event. We found that overcompensation occurred with the most adults produced at medium levels of mortality (500 larvae/L). Our results suggest that middle densities of Ae. aegypti larvae, simulating medium levels of control, will produce the most adult females with a relatively large body size. Based on these results and their corroboration of other observations of overcompensation occurring in Ae. aegypti, we recommend that compensation be considered as a possible outcome of Ae. aegypti larval control campaigns and that high levels of larval suppression are recommended to reduce adult populations.