Autogeny in Culex pipiens complex mosquitoes from the San Francisco Bay Area

We surveyed the genetic ancestry and recorded the occurrence of autogeny, the developmental times, and survival rates in families of Culex pipiens in Santa Clara County, CA, at 37°N latitude. Females in 95% of the families produced fertile egg rafts without access to blood (= autogeny) after mating in stenogamous conditions. Developmental time, survival, and egg raft production were closely correlated to temperature. Male DV/D ratios overwhelmingly matched Cx. pipiens but a microsatellite analysis revealed these were Cx. pipiens form molestus hybridized with Culex quinquefasciatus and to a lesser extent to Cx. pipiens form pipiens, a genetic mix heretofore not recorded elsewhere. Greater DV/D ratios and larger proportions of genetic ancestry from Cx. quinquefasciatus were negatively correlated to autogeny. The combination of multiple overwintering strategies and widespread autogeny in females arising from aboveground larval sites supports the hypothesis that some North American populations of Cx. pipiens complex mosquitoes express unusual phenologies.