Species: Aedes trivittatus


This mosquito is an aggressive human biter often attacking hosts in a swarm-like manner. Human populations in close proximity to emergence sites are at greatest risk since these mosquitoes do not migrate very far from their breeding grounds. This species is a possible vector of canine heartworm but it is has not been involved with transmission of encephalitic viruses.


Ae. trivittatus is found primarily in states east of the Rocky Mountains. It has been collected throughout Montana with highest densities in the northcentral and eastern parts of the state. Collections have also been made in western Montana. Larvae can be found in a variety of freshwater habitats especially ones associated with riparian areas and river drainages and can tolerate relatively high alkaline water. Light traps are considered ineffective at assessing adult populations of Ae. trivittatus. It has been reported that populations of this species can be high while light trap catches remain low. Landing rate collections or resting boxes placed in thick vegetative cover reportedly provide better population density estimates.

Identifying Characteristics:

Small mosquito, pointed abdomen, no leg bands, top of thorax with 2 pale stripes (often rubbed off from handling), triangular-shaped pattern of pale scales on sides of abdomen. Similar to Ae. sticticus.

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)