Environmental predictors and blood meal analysis of an important West Nile virus vector (Culex restuans) in ruffed grouse habitat

West Nile virus (WNV) was first detected in 1999 in New York City from American Crows; by 2000, the virus reached Pennsylvania. Less than a year later, in 2001, Ruffed Grouse (Bonasa umbellus) populations were determined to be declining, corresponding with the prevalence of WNV. The overarching hypothesis is that WNV was negatively affecting grouse in their habitats. However, trapping, handling, and sampling grouse for WNV is time intensive and costly. One way to assess whether WNV is affecting the grouse is to use their historical habitat as an index in Luzerne County, Pennsylvania. First, gravid trap surveys (1/week) of mosquitos were conducted to assess the mosquito community composition at eight sites. Culex restuans, an avian blood specialist, is a particularly important vector of the virus. Pennsylvania Department of Environmental Protection (PA DEP) conducted subsequent assays of trapped mosquitoes for the prevalence of WNV. Additionally, modified point counts were conducted to detect Ruffed Grouse and other potential avian hosts. Blood meals were also analyzed within targets using cytochrome c oxidase subunit 1 gene for host identification. By trapping mosquitoes on a regular basis over the breeding season of birds, was able to ascertain whether particular environmental conditions (e.g., temperature, precipitation, humidity, elevation, and human disturbance) predict vector abundance and community dominance. This was able to detect a wide range of mosquito abundance among the sites (0 to 240 individuals / sampling point). Low elevation, high human disturbance, high temperature, high humidity, and low precipitation scaled positively with mosquito abundance. In areas containing WNV, there was higher overall bird abundance (N= 445), higher Passeriformes abundance (N=372), and greater bird species diversity (N= 55). Grouse were detected on only four sites. The blood meal analysis identified four passerine bird species none of which are deemed “sensitive” to WNV. In conclusion, limiting stagnant water pools in areas near human disturbance and where there is high bird abundance and high Passeriformes abundance will aid in the decrease of potential WNV vectors in the area. This will then help limit the WNV infection to potential high-risk bird species that are in these areas, like the Ruffed Grouse.