Dispersal biology of invasive Aedes aegypti mosquito populations

Project Summary Accurately estimating dispersal and population size of highly invasive Aedes mosquito species is an essential, but particularly challenging, aspect of designing and optimizing effective vector control programs. Aedes aegypti can spread dengue fever, chikungunya, Zika fever, and yellow fever viruses - all of which have had a profound impact on human health. Results of our recent study on Californian Ae. aegypti populations show dispersal distance based on genome-wide rare mutations closely reflects the known mosquito invasion history providing a promising new approach to estimating dispersal distance. Moreover, we have identified multiple genetic clusters of Ae. aegypti mosquitoes with varying frequency of insecticide resistance mutations, suggesting different selection forces influencing their genetics that, in turn, may impact the efficacy of mosquito control. What remains lacking is rigorous scientific evidence supporting the effectiveness of population genomics approaches to accurately estimate Ae. aegypti dispersal and population size as well as identifying genetic elements facilitating their local adaptation, further spread, and establishment in new environments. There is, therefore, a critical need to determine the efficacy of population genomic approaches in estimation of dispersal and population size of Ae. aegypti mosquitoes and genes under selection in different environmental settings. My long-term goal is to become an independent teacher-scholar focused on advancing understanding of how evolutionary forces shape mosquito dispersal and population size and contributing toward the development of effective, efficient, and sustainable mosquito control strategies. My objectives are (1) to determine genetic relatedness and effective population size (Ne), and (2) identify population-specific genes under selection shaping local adaptation of invasive mosquito populations using population genomic approaches. My central hypothesis is that a mosquito genome undergoes local adaptation as it invades new environments. The rationale for the proposed research is that detailed understanding of the genetics of local mosquito populations is likely to contribute meaningfully toward a new integrated mosquito management (IMM) strategy that leverages genetic biocontrol methods. At the completion of the proposed project, I expect to have produced estimates of genetic relatedness between Ae. aegypti populations from diverse environments (Pacific, Caribbean, and mainland USA) and determined Ne per city and county level (Aim 1). In addition, I anticipate having identified sets of genes under selection from different environments illuminating demographic history and evolutionary forces shaping local adaptation (Aim 2). These results are expected to have an important positive impact on improving invasive mosquito control capacity through improved understanding of invasive Ae. aegypti mosquito dispersal and enhancing the readiness of the public health officers in detecting and responding to invasive mosquito species.