Genetic diversity of Aedes vexans (Diptera, Culicidae) from New Orleans: pre- and post-Katrina

The floodwater mosquito Aedes vexans, a potential vector of West Nile virus, has a worldwide distribution that includes the continental United States and southern Canada. In order to determine the effect that Hurricane Katrina had on the temporal genetic variation of Ae. vexans from New Orleans, we compared genetic diversity of a portion of the mtDNA ND5 gene of mosquito specimens collected during 2005 (n = 99) with specimens from 2006 (n = 103), after the hurricane. Average haplotype diversity (Hd) was high (>0.88) in 2005 and 2006 for both the parishes studied. It does not appear that Hurricane Katrina had any impact on genetic diversity, and despite the intense efforts to control mosquitoes in New Orleans, Ae. vexans has not undergone a population bottleneck. A bottleneck effect may be lacking because this species breeds outside the city and the adults migrate into the city.