SPATIAL-DISTRIBUTION OF ADULT MOSQUITOS (DIPTERA, CULICIDAE) IN HABITATS ASSOCIATED WITH THE RICE AGROECOSYSTEM OF NORTHERN CALIFORNIA

The objective of this study was to determine whether abundance, blood feeding rates, and sex ratios of adult Anopheles freeborni Aitken and Culex tarsalis Coquillett were associated significantly with either ri ce field, pasture, riparian, or mixed habitats found within tile rice culture agroecosystem of northern California. Significantly higher num bers of adult An. freeborni occurred in riparian and mixed habitats co mpared with lice and pasture habitats. Such a pattern was not evident for Cs, tarsalis. Riparian and pasture habitats contained significantl y higher proportions of blood fed Ati. freeborni females than did lice and mixed habitats; however, the proportions of blood fed Cx. tarsali s females did not vary significantly among habitat types. The proporti ons of blood fed An. freeborni and Cx. tarsalis females in riparian ha bitats decreased with increasing abundance. There was no correlation b etween blood feeding rates and abundance for An. freeborni and Cs. tar salis females in the other habitat types. Tile sc?: ratio of An, freeb orni in pasture and riparian habitats was significantly female biased, unlike the other habitats which did nor differ significantly from uni ty (1:1). Overall, riparian and mixed habitats contained greater numbe rs of adult mosquitoes; therefore,surveillance and control efforts of these mosquito species should be focused on such habitats.