Time of host-seeking by Culex tarsalis (Diptera:Culicidae) in California.

Factors altering the pattern of Culex tarsalis Coquillett host-seeking activity were studied in Kern and Riverside counties of California using an automatic time-segregated sampler baited with bottled CO2 gas released at 0.5 or 1.0 liters/min. Host-seeking always commenced shortly after sunset and usually peaked during the succeeding 1-3 h, the hottest and driest time of the night. The time of maximal activity varied over time and space, because of increased mosquito abundance (presumably reduced blood feeding success), distance of the sampler from resting sites, adulticide applications, and perhaps weather.