Bionomics of Culiseta particeps in southern California.

The distribution of Culiseta particeps (Adams) in California appears to be restricted in Califor-nia to the Pacific coastal areas and scattered patches in the Riverside and San Bernardino counties (Darsie and Ward 1981). However, Iit-tle information exists on the adult ecology and abundance of this species. Larvae have been found in marshes, margins of streams, residual pools in stream beds and margins of. large Ty-pha-filled, pools (Seamen 1945, Bohart and Washino 1978). In biting and light trap collections , adults have been collected in small numbers in barns (Seamen 1945). Colonization of this species has been accomplished by Chapman and Barr (1969) for at least half a year. Although an unidentified bunyavirsus was recently isolated from a pool of adult females (Emmons et al. 1988), Cs. particeps has yet to be considered as an important pest or vector of any disease (Bohart and Washino 1978). Studies relating to adult population abundance and host-seeking activities were initiated at a dairy operation near Norco, Riverside Co., California. The study site and sampling methods have previously been described (Schreiber et al. 1988). Briefly, the study area was located at a dairy/truck crop farm 1 km west of the city of Norco, adjacent to backwater from the Santa Ana River. During this study, five distinct habitats were monitored by unlit dry ice baited CDC traps: Habitat 1, east of the dairy proper in the truck crop field; Habitat 2, the dairy/lagoons proper; Habitat 3, tree rows adjacent to the dairy and lagoons; Habitat 4, just west from the lagoons in a tree row along the interface of the dairy and a horse/cattle pasture; and Habitat 5, in a riparian habitat with backwater from the Santa Ana River and lagoon overflow. In each habitat, two sites were used to trap host-seeking adult mosquitoes on a twice a month basis from June 4, 1987, through June 9, 1988; no collections were made during January 1988. Landing and biting activity of female mosquitoes was assessed at night in a location near the dairy Iagoons. Ten minute landing counts were made on a human subject (ETS), and the alighting mosquitoes were collected with a battery-powered aspirator. These studies were conducted throughout the night on each trapping occasion. Since landing counts were 10 min in duration, and the CDC traps (10) were run on an hourly basis, comparison between the two methods was corrected for a per hour effort …