Feeding Success and Host Selection by Culex quinquefasciatus Say Mosquitoes in Experimental Trials.

Arthropod vector feeding preferences are defined as an overutilization of a particular host species given its abundance in relationship to other species in the community. Numerous methods exist to quantify vector feeding preferences; however, controlled host choice experiments are generally an underutilized approach. In this report, we present results from controlled vector host choice experiments using Culex quinquefasciatus Say (Diptera: Culicidae) mosquitoes and wild avian hosts identified as important contributors to West Nile virus (WNv) transmission in Atlanta, Georgia, United States. In each experiment, we allowed lab-reared F1 Cx. quinquefasciatus to feed freely overnight on two avian individuals of a different species (i.e., northern cardinals, American robins, blue jays, brown thrashers, and gray catbirds). We then estimated WNv transmission potential using vectorial capacity and R0. We found that mosquito blood feeding success was extremely variable among experimental replicates and that patterns of host choice only occasionally aggregated to a particular bird species. Vectorial capacity was highest for American robins and blue jays due to these species' higher reservoir competence for WNv and greater probabilities of mosquito selection of these species. Despite species-specific differences in vectorial capacity, total community capacity was similar among species pairs. R0 estimates were qualitatively similar to capacity, and R0 was below and above unity across species pairs. Our results provide empirical evidence that C. quinquefasciatus is an opportunistic blood feeder and highlight how variability in vector-host contact rates as well as host community composition can influence the likelihood of WNv transmission in avian communities.