E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Aedes togoi (Theobald)
Family: Culicidae
Species account author: Peter Belton.
Extracted from The Mosquitoes of British Columbia (1983)
Photo of species

© Peter Belton  Email the photographer   (Photo ID #1243)

E-Fauna BC Static Map
Distribution of Aedes togoi in British Columbia
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Species Information

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Illustration 2

A large, elegantly marked mosquito with distinctively banded tarsi; wing length 5 mm. It is restricted to rocky coastal areas.


Proboscis uniformly dark. Palps dark, tipped with silver scales. Pedicels silver scaled on dorsomedian surface. Scutum predominantly brown to the naked eye, with six longitudinal stripes of golden scales, broadening anteriorly; curve of outermost stripes following suture, to scutal angle. Prescutellar space bordered by golden brown scales. Postprocoxal and hypostigmal areas bare. 4 lower mesepimeral setae. Abdominal tergites with dark brown scales and silvery white basal bands widening laterally. Dark scales of abdomen and legs with blue-green iridescence. Upper surfaces of femora and tibiae dark, pale scales below. Tarsomeres with white basal and apical bands, basal bands lacking on segment 5 in some specimens. Wings dark-scaled, a few pale scales at base of C.


Head setae 5 and 6-C close to anterior margin of head, 6 or more-branched. Comb scales slipper-shaped, small and very numerous (50-100 or more) in a semicircular patch. Siphon short, 2-2½ x 1, pecten teeth even, extending beyond middle. 1-S large many-branched, inserted beyond pecten. Saddle small, 1-X long unbranched, not inserted on saddle. Papillae very short, almost hemispherical.

Glossary of Terms [PDF]

Genus Description

Aëdes is the Greek word for disagreeable. Without the dieresis the word means house or building. Although Meigen did not use a dieresis, he translated it as troublesome. Some authorities, therefore, write the generic name Aëdes. Most species of British Columbian mosquitoes belong to this genus. The females all have short palps, usually less than one quarter of the length of the proboscis, and in both sexes the posterior margin of the scutellum is tri-lobed with the setae in three tufts.

Aedes is a large and variable genus and in the field the most reliable character to separate females from other mosquito genera is the pointed abdomen. Males can be identified in the field by their large and separated gonocoxites but if these are not obvious the thorax can be examined for the presence of postspiracular setae which are absent in the males of Culex, Culiseta, and Mansonia. A slide of the terminalia, as well as confirming the genus, can be used to determine the species. (See Wood et at. 1979).

When at the water surface, the larvae of all culicines hang downwards from the hydrophobic tip of the siphon and are thus easily distinguished from anophelines.

Aedes larvae can be distinguished from those of Culex and Culiseta by the position of the siphon seta (1-S). It is never at the base of the siphon in aedines and can be seen with a hand lens if the larva cooperates.

The pupae are hard to identify. It is usually simpler to let them emerge.

Nearly all aedine adults in British Columbia die in late summer or autumn. The eggs are laid singly or in clusters, usually in crevices at the margins of suitable breeding sites. They do not float. Most aedines overwinter as eggs.


Species Information

In North America, this species was first collected from Cordova Bay, Vancouver Island, by Dr. R. Ring of the University of Victoria, and shown at the meeting of the Canadian Entomological Society there in 1971. An adult specimen in the Canadian National Collection, however, appears to have been collected 20 years earlier at Horseshoe Bay by C. D. Garrett. Dr. M. Trimble and I have found it on the Gulf Islands, all along the Sechelt Peninsula and on Howe Sound, 46 km north of Horseshoe Bay. This species may have been introduced from Japan as Wood et at. (1979) suggest, but when milder climates prevailed, it could have been widely distributed around the Pacific rim. If its range is found to extend further north, I would find it difficult to believe that it is a recently introduced species. The larvae are found in rock pools just above high tide. They can easily be overlooked as they are able to remain for long periods in the debris at the bottom of the pools without surfacing. Adults bite humans readily but do not fly far from shore. Ae. togoi can transmit several diseases including Japanese B encephalitis and filariasis in Malaya, Japan and the coastal area of U.S.S.R. north of the Sea of Japan (La Casse & Yamaguti 1950). Fortunately these diseases do not occur in British Columbia.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
ExoticSNAExoticNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Notes

"This species could be as important a vector of West Nile Virus (WNv) as the two other species introduced from Asia, Aedes albopictus and Aedes japonicus established in the east. The last is now also established in western WA not far from our border. All 3 feed during the day on a variety of hosts. Fortunately our species has not spread inland from its favoured coastal rock pools but it is distributed widely around the Georgia Strait, the Gulf Islands and the Washington coast. In Asia, Aedes togoi is an important vector of Japanese Encephalitis, a virus of the same serotype, (B), as WNv. It breeds year round, overwintering as 4th stage larvae or eggs, feeds on birds and mammals and is often common enough to be a pest to seaside homeowners." (Belton 2007, with permission).


Belton, Peter. 2007. British Columbia mosquitoes as vectors of West Nile virus. Peter Belton web site. Simon Fraser University.

Synonyms and Alternate Names

Ochlerotatus togoi (Theobald)

Additional Photo Sources

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-06-15 1:21:12 PM]
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