Culex tarsalis

Culex tarsalis is frequently encountered at lower elevations in the valleys in Teton County.  Its larvae are found in permanent water sources and some semi-permanent sources such as hay and pasture that have been flooded for extended periods of time.  Cx. tarsalis is important because of its role in the transmission of West Nile virus.  Although many species found in Teton County may transmit WNv, Cx. tarsalis is the most efficient local vector of the disease, transmitting the disease between its natural bird hosts and other dead-end hosts including human and horses.  Image from Carpenter & LaCasse,1955.