Blood-Feeding Behavior of Culex tarsalis at Medicine Lake National Wildlife Refuge, Montana

Abstract

It is known that the ornithophillic mosquito, Culex tarsalis is the primary vector of West Nile Virus (WNV) in Montana. An analysis of this mosquito’s blood feeding behavior allows researchers to identify preferred hosts and to determine the rate at which this species parasitizes humans and other tangential hosts. Additionally, an understanding of blood feeding behavior allows an assessment of WNV risk based on the regional availability of preferred hosts and the hosts’ competency in viral amplification. In this study, blood engorged Cx. tarsalis were captured at Medicine Lake National Wildlife Refuge over three one-week periods spaced through early, middle, and late summer. Vertebrate DNA was isolated from mosquito blood meals and a fragment of the COI gene was PCR amplified to determine host species. Additionally, avian surveys were conducted at mosquito collection sites so that each bird’s relative abundance could be compared to its incidence in blood meals. The two most common host species were the Mourning Dove comprising 59% of blood meals and the American Robin comprising 33%. These species were ranked 4th and 14th, respectively in observed abundance out of the 47 species counted in this study. These results suggest that Cx. tarsalis at Medicine Lake NWR exhibits a feeding preference for these two species.