Species: Coquillettidia perturbans


This species has been documented as a vector of WNV and eastern equine encephalitis (EEE). Although it is not the primary vector of EEE, its role in transmission influences the spread of this disease due to its ability to fly long distances and feed on large animals, including humans.


Cq. perturbans is found in the eastern half of the U.S., along the west coast, and small parts of Idaho, Montana, Colorado, and Utah. In Canada the species is found along the country’s southern border. Eggs are laid on the water surface in areas of heavy emergent vegetation. After hatching, the larvae insert a modified siphon into the roots of submerged stems of plants to obtain oxygen and remain attached for the greater part of the year. Pupae also attach to plants using their modified respiratory trumpets. Thus, larvae and pupae of this species are not readily collected because of their habit of remaining permanently under water attached to aquatic plants. The winter is passed in the larval stage. There is one generation a year; the adults appear in late spring and summer.

Identifying Characteristics:

Rounded abdomen, most scales on dorsal surface of wing very broad, hindtarsomeres with pale bands basally, may have a band of pale scales on the proboscis. May be misidentified as Cx. tarsalis to the untrained eye.

Distribution Map:

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Mosquito and Vector Surveillance Program

MSU Extension - Department of Animal and Range Sciences

Montana State University
P.O. Box 172900
Bozeman, MT 50717-2900

Location: Marsh Labs, Room 59

Veterinary Entomology Research Associate:

Marni Rolston

Professor Emeritus of Veterinary Entomology:

Dr. Greg Johnson


Dr. Grant Hokit (Carroll College)