Avian host preference of Culex mosquitoes in southern California

The host preference of a vector mosquito species plays a significant role in determining human and animal risk of infection with mosquito-transmitted pathogens. Host preferences of common southern California Culex species for four bird species, American crow (Corvus brachyrhynchos), house sparrow (Passer domesticus), house finch (Carpodacus mexicanus), and mourning dove (Zenaida macroura), were examined by determining the proportion of each mosquito species that successfully engorged on each of the four bird species presented equally within a net trap to wild host-seeking mosquitoes. Blood meals in engorged mosquitoes captured within the net trap were identified to avian species using a multiplex PCR assay targeting the cytochrome b gene sequence.  There were significant differences in host selection by all three Culex species captured in numbers sufficient for analysis, with Cx. erythrothorax Dyar preferentially biting American crows, Cx. tarsalis Coquillett preferentially biting house sparrows, and Cx. quinquefasciatus Say preferentially biting house finches.  All three Culex species demonstrated more frequent engorgement on passerine birds (sparrows, finches, and crows) than the non-passerine mourning dove. A greater preference for passerine birds might be expected to increase the transmission of pathogens, like West Nile virus, to which passerine birds are particularly competent hosts.