West Nile virus infection and environmental temperature alters life history traits of Culex pipiens quinquefasciatus (Diptera: Culicidae)

Culex pipiens quinquefasciatus is a vector of filarial nematodes and arboviruses affecting public and veterinary health. In the United States, Cx. p. quinquefasciatus is the main vector of St. Louis encephalitis virus and may play a role in the maintenance of West Nile virus (WNV) in bird populations as well as transmission to humans. It is often assumed that arbovirus infection has inconsequential effects on mosquito fitness. However, arbovirus infection has been shown in some instances to cause cytopathological effects on mosquito organs and changes in behavior. We investigated the effect of WNV infection on timing of oviposition and survivorship of adult Cx. p. quinquefasciatus females. Females infected with WNV had significantly delayed oviposition and lower longevity compared to uninfected control groups at 32°C. Conversely, there were no significant differences in oviposition or longevity between WNV-infected and uninfected control groups at 28°C. These results suggest that WNV infection compromises mosquito fitness and, hence, vector capacity, but these effects are contingent on the interaction with factors such as environmental temperature. This species is found in areas with temperature ranges beyond the two points used here, so these effects could impact seasonal and regional differences in Cx. p. quinquefasciatus vectorial capacity for WNV.