Rainfall Influences Survival of <I>Culex pipien</I>s (Diptera: Culicidae) in a Residential Neighborhood in the Mid-Atlantic United States

Abstract

Measurement of the survival and dispersal rates of mosquito vectors is an important step in designing and implementing control strategies. Vector survival plays a key role in determining the intensity of pathogen transmission, and vector movement determines the spatial scale on which control efforts must operate to be effective. We provide the first estimates of field survival and dispersal rates for Culex pipiens L. in North America, an important enzootic and bridge vector for West Nile virus (WNV). We conducted mark-release-recapture studies in a residential area near Washington, DC, in two consecutive years and fit nonlinear regression models to the recapture data that incorporate weather information into survival and recapture probabilities. We found that daily survival rates were not significantly different between the 2 yr but were negatively affected by rainfall. The daily survival rate was 0.904 ± 0.037 (SE), which implies an average longevity of 10.4 d. As with other vector-borne pathogens, the measured survival rate suggests that at our site the majority of WNV-infected Cx. pipiens mosquitoes may perish before becoming infectious (being able to transmit WNV to hosts). We found relatively little evidence of dispersal after the initial night after release. Our results suggest that transmission of WNV and other pathogens transmitted by Cx. pipiens may be highly local and they highlight the importance of factors that influence survival of mosquito vectors.