MARK-RELEASE-RECAPTURE STUDIES WITH AEDES DORSALIS (DIPTERA, CULICIDAE) IN COASTAL NORTHERN CALIFORNIA

Two mark-release-recapture studies were conducted along the Sacramento -San Joaquin River Delta in northern California to describe the popula tion ecology and dispersal pattern of Aedes dorsalis (Meigen). Immatur e Ae. dorsalis were collected from saline tidal marshes, reared to adu lts, marked, and released. Recapture grids during the July and Septemb er studies were within 8.0 and 2.4 km of the release sites, and recapt ure rates were 0.1 and 1.2%, respectively. The longest recorded flight was 5.8 km, and mosquitoes were recaptured up to 15 d after release. In September, 84% of the marked mosquitoes were : recaptured within 2. 0 km of the release site, and the mean dispersal distance was 1.9 km. Marked mosquitoes flew predominantly downwind to the east. There was n o evidence that Ae. dursalis traversed the 1.6-km-wide river from Cont ra Costa to Solano County. Temporal and spatial recapture patterns ind icated a possible short-range migration pattern from oviposition sites to upland host-seeking areas. Changes in the recapture rate with coho rt age delineated a 7-d gonotrophic cycle during September.