Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

Species Ochlerotatus triseriatus - Eastern Treehole Mosquito

mosquito - Ochlerotatus triseriatus - female Culex? - Ochlerotatus triseriatus eastern treehole mosquito - Ochlerotatus triseriatus - female eastern treehole mosquito - Ochlerotatus triseriatus - female eastern treehole mosquito - Ochlerotatus triseriatus - female Mosquito biting arm - Ochlerotatus triseriatus - female swatted eastern treehole mosquito - Ochlerotatus triseriatus - female eastern treehole mosquito - Ochlerotatus triseriatus - female
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon ("Nematocera" (Non-Brachycera))
Infraorder Culicomorpha (Mosquitoes and Midges)
Family Culicidae (Mosquitoes)
Tribe Aedini
Genus Ochlerotatus
Species triseriatus (Eastern Treehole Mosquito)
Other Common Names
"Tris"
Pronunciation
tri-ser-ee-yay-tus
Synonyms and other taxonomic changes
Ochlerotatus triseriatus (Say)
Orig. Comb: Culex triseriatus Say 1823
Syn: Aedes triseriatus (Say)
Identification
- top of scutum dark - FMEL
- patch of white scales along edge of scutum; legs dark - FMEL
Adult Female:
- Legs, wings and proboscis are completely darkscaled
- The abdomen is mainly dark scaled with only the margins of the last four segments with pale patches
- Scutum with dark reddish brown broad medial band contrasting with silver scales laterally*
Range
e US (TX-FL-ON-ND) (Walker 1992)
Habitat
The larvae live in temporary tree holes.
Even though the accepted common name for "Tris" is the eastern treehole mosquito, it also breeds in tires, mainly in shaded locations. It can be found in a single water-filled tire behind the garage or in a tire dump with thousands of tires. In scrap tire yards, adults reach incredibly high numbers, as many as 60,000 females per acre in mid-summer. Ochlerotatus triseriatus has become an important urban mosquito because of its association with scrap tires. (Walker 1992)
Season
Larvae: May - September
Adults: June - October
Food
Females prefer blood from mammals and reptiles.
Few mosquito species feed rodents. These mammals are just too jittery and quick to sit still for that. But Ochlerotatus triseriatus, even though it bites a wide variety of mammals, including humans and sometimes birds, particularly likes chipmunks squirrels. These woodland rodents are active during the day when Ochlerotatus triseriatus is seeking hosts in the woods. (Walker 1992)
Life Cycle
Overwinters as an egg. It has many generations per year (multivoltine).
Remarks
Primary vector of LaCrosse Encephalitis virus. Females will bite anytime of day.
Ochlerotatus triseriatus is not the mosquito that you slap in the evening, or the one that has Joe Public on the phone all summer long with complaint calls. It just isn't all that abundant in most places in its range. Ochlerotatus triseriatus never drew much attention until it was found to be the vector of La Crosse encephalitis virus. La Crosse encephalitis is primarily a problem of children in the upper Midwest and east. Symptoms can range from a mild flu-like illness to seizures and coma. Ohio leads the nation in number of cases, followed by Wisconsin, Minnesota, Illinois and Indiana. Outside this "LaCrosse encephalitis crescent," cases occur in Texas, North Carolina, Michigan, Missouri, Iowa, West Virginia and New York. (Walker 1992)

filial infection is important for the La Crosse virus, which causes serious brain disease or death in about 72 Americans each year, most of them children. That virus is transmitted to humans by Aedes triseriatus, a forest mosquito that picks it up from chipmunks.
La Crosse virus passes down easily in mosquito eggs; about 70 percent of mosquito females maturing from those eggs inherit the virus, Dr. Tesh said. NYTimes, 2016
See Also
Ochlerotatus thibaulti has golden scales laterally
Print References
Walker, N. 1992. The eastern treehole mosquito, Aedes triseriatus. Wing Beats, Vol. 3(2): 17.
Internet References