Habitat associations of hybrid populations of the Culex pipiens complex

The Culex pipiens mosquito complex is one of the vectors of West Nile Virus. West Nile Virus was first detected in the U.S in 1999 in New York and has since spread throughout the United States. In California, C. pipiens is found in northern California, while C. quinquefasciatus is found in southern California. Merced County in the Central Valley of California is in the hybrid zone for these two mosquitoes. Hybrids of the C. pipiens complex have been shown to have a higher incidence of West Nile Virus. We investigated whether hybrids of Culex pipiens and C. quinquefasciatus in Merced County occur more frequently in a particular habitat. Habitats sampled include rural, suburban, and urban areas, as well as near dairies and natural wetland sites. Mosquito samples were collected by the Merced County Mosquito Abatement District using carbon dioxide baited CDC traps. DNA was extracted from mosquito legs and used to produce amplified fragment length polymorphisms (AFLPs) to determine the proportion of hybrids in each habitat. The incidence of West Nile Virus was also determined in a subset of mosquitoes from each habitat type. The results will help to target management of these mosquitoes in particular habitats in order to reduce the incidence of West Nile Virus.