Date of Award

Spring 5-13-2017

Document Type



Life & Environmental Sciences


West Nile Virus (WNV) is an increasing problem worldwide due to vector competence and enzootic transmissibility between vector and host. The most prevalent vector of WNV in the state of Montana is the Culex tarsalis mosquito, which is found in varying ecological conditions such as shallow, standing water and at high temperatures (14°C – 34°C). These conditions are not well understood in Montana, thus limiting predictions concerning potential outbreaks. This study tested the ecological effects on C. tarsalis and found that land cover and May precipitation were significant factors that affect the ability of C. tarsalis to thrive in Montana, with May precipitation being negatively associated with C. tarsalis abundance. Land cover classified as sagebrush steppe had a greater abundance of C. tarsalis than did lowland prairie grassland and wetland riparian, with modified agricultural lands having the lowest abundance of C. tarsalis. A better understanding of the predictive ecological factors of C. tarsalis will allow state officials to predict when outbreaks may become prevalent.