D3402: Population dynamics at an invasive front – Aedes aegypti in the American southwest

The expansion of Aedes aegypti populations in the American Southwest (ASW), a region characterized by large urban centers dispersed within a (semi)arid ecoregion, presents a unique opportunity to investigate the dynamics of invasion, localized adaptation, and subsequent population differentiation of Ae. aegypti in novel environments. To define population structure in Texas, we collected and genotyped adult male and female mosquitoes from Ft. Worth, El Paso, Lubbock, and Edinburg in 2022. Combined with previously derived genotyping information from El Paso (2017), Houston (2011 and 2017), Bexar County (2017), and Slaton (2017), we quantified the spatiotemporal population structure of Ae. aegypti. Preliminary analyses identify 3-4 clusters of sub-populations and patterns of isolation by distance (mean Fst 0.09). Effective population size calculations ranged from 1.6 to greater than 1300, with lower estimates more common for northern and western samples. These results, in combination with ongoing studies, will reveal the directionality of invasion, generate evidence of localized adaptation, and identity key population-level targets for the design of successful Ae. aegypti surveillance and control interventions in the ASW.