Genetic Identification of Culex tarsalis Host Plants from Extracted Gut Contents
Since its introduction to the United States in 1999, West Nile Virus (WNV) has become the most prevalent arthropod borne virus (arbovirus) in the Americas. WNV possesses the potential to manifest encephalitic symptoms in both humans and horses, making it an area of constant concern. The most common vector of WNV in the Western United States is the mosquito Culex tarsalis, which likely derives WNV from migrating bird populations that act as viral reservoirs. C. tarsalis blood feeds specifically for nutrients needed in reproduction, and imbibes floral nectar or other plant sugars for energy. Work with other mosquito species, including members of the genus Culex, suggests that there are definite preferences in the kinds of plants for which mosquitoes forage. Using the contents of extracted mosquito guts, it has been demonstrated that the identity of host plants can be determined through genetic methods. This study uses these methods in an attempt to identify popular host plants among C. tarsalis females residing in wetlands near Helena, Montana with the hypothesis that C. tarsalis selectively forages for floral nectar in a wetland environment, and does not simply feed on the flowers which are most abundant given vegetative data. While no determinations of host plant preference can be made with certainty due to inconclusive PCR results, Cirsium arvense is implicated as a possible sugar source due to its high nectar content and relative abundance.