Aedes aegypti: Eco-evolutionary Dynamics, Gene drives, and Sex-Ratios

Mosquito-borne diseases pose a persistent global health threat. Traditionally managed with insecticides, approaches to combat this threat must address insecticide resistance and ecological concerns of the environment. Novel vector control strategies employing the release of sterile/irradiated, Wolbachia-infected, or genetically modified Aedes aegypti mosquitoes offer potentially more sustainable alternatives by reducing vector populations. However, the successful and safe implementation of these innovative technologies necessitates a thorough understanding of complex eco-evolutionary dynamics including: potential density-dependent feedback mechanisms, the role of sex ratios of breeders, and the impact of environmental factors like water depth and food availability on larval development; it is also imperative to integrate understanding of these dynamics into risk-benefit assessments and release strategies. Herein, this dissertation reviews the current status, successes, and limitations of these three mosquito modification approaches, in concert with original experimental investigations into (1) whether female A. aegypti can sense and alter offspring sex ratios in response to male-biased adult populations, a scenario relevant to many vector control interventions, and (2) how varying water depths and food availability affect A. aegypti larval development, survival, and adult fitness under controlled laboratory conditions.

The dissertation emphasizes critical eco-evolutionary questions that must be addressed through rigorous laboratory and field research – before, during, and after mosquito releases – to predict their efficacy, optimize release parameters, anticipate potential ecological impacts (considering the mosquito's role in the ecosystem), and ensure their responsible deployment with community engagement. This work highlights the importance of considering species-specific traits, genetic variation, competitiveness, adaptation, long-term ecological consequences, the resilience of natural sex ratio regulation, the influence of larval environmental conditions (including water type and container characteristics) on adult traits, and the need for transparent communication and community involvement. Then this dissertation underscores the need for a holistic, eco-evolutionary informed framework to guide the development and implementation of modified mosquito-based vector control strategies for sustainable and impactful outcomes, further informing the minimal resource requirements for mosquito development.