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Culex territans Walker

by Wayne J. Crans, Rutgers University

Subgenus : Neoculex

Type of Life Cycle : Culex pipiens Type

Typical Habitat : Permanent and semi-permanent clear water swamps containing liberal stands of emergent grasses

Larvae Present : Early spring through late fall

Head Hairs :

Upper: Single (Occasionally double)

Lower : Single (Rarely double)


Length: As long as head, constricted beyond tuft

Tuft: Large, multiple, inserted on outer 1/3 of shaft

Abdominal Hairs (Segments III-VI) : 2-2-2-2

Comb Scales : Large patch


Index: 6.0-7.0

Tufts: 4-5 pairs, inserted beyond the pecten

Pecten: Evenly spaced on basal 1/3 of siphon

Anal Segment:

Saddle: Complete ring

Precratal tufts: 2 or 3

GEOGRAPHIC DISTRIBUTION: Culex territans has a distribution that includes both the new and old worlds. The mosquito is quite common throughout most of eastern Europe and is even found in parts of Africa. In North America, Cx. territans extends from Alaska and Canada south through most of the United States. The mosquito is widespread in New Jersey with records from every county. The mosquito reaches greatest numbers in areas where clear grassy bogs and ponds provide suitable breeding habitat but specimens have also been documented from some of the more urbanized areas of the state .

SEASONAL DISTRIBUTION: Culex territans has a life cycle that is typical for most Culex species. In late fall, inseminated adult females feed on carbohydrates and hibernate in subterranean enclosures where they pass the winter in a state of torpor. The mosquitoes emerge in very early spring, obtain a blood meal and lay the first egg rafts of the season. Culex territans is a frog feeder and it is not uncommon to see this species feeding on Spring Peepers during the month of March in southern New Jersey. Egg hatch, however, may be delayed because of the mosquito's unique oviposition habits. Unlike most Culex, Cx. territans females rarely deposit their egg rafts directly on the surface of the water. This mosquito normally positions the raft up on the bank and relies on rainfall or rising water levels to flush the eggs onto the water's surface. Culex territans shares habitat with many of the univoltine Aedes in early spring, a variety of Anopheles sp. later in the summer and Uranotainia sapphirina very late in the season. Larvae generally can be collected through the month of September in most areas of New Jersey.

LARVAL HABITAT: Culex territans is found in a wide variety of clear water habitats that support grassy stands of emergent vegetation. The species is occasionally found in containers but cannot tolerate even moderate levels of pollution. Culex territans is common in farm ponds, swamps and bogs and roadside ditches. In northern New Jersey, the mosquito is widespread in beaver swamps. In southern New Jersey, the mosquito is very common in acid water spagnum bogs. Culex territans is one of the few species that can be collected from streams. It is not uncommon to find larvae within the grassy margins of slow moving streams and specimens are sometimes found in rock pool habitats normally associated with Aedes atropalpus.

COMMON ASSOCIATE SPECIES: Ae. abserratus, Ae. fitchi, Ae, aurifer, An. walkeri, Cs. morsitans, An. quadrimaculatus, An. punctipennis, Ur. sapphirina

LARVAL COLLECTION: Culex territans are usually very common in typical habitats and no special techniques are needed to collect specimens. Dipping in stands of emergent grasses increases the chances of finding larvae. Searching for shaded areas within sunlit pools can be productive because the larvae favor shade on bright days. Culex territans is a mosquito that prefers cool water habitats. Focusing attention toward areas of seepage can be productive in habitats where this mosquito is sparse.

LARVAL IDENTIFICATION: Culex territans larvae are very easy to recognize in the dipper. Their small size, extremely long air tube, prominent antennae and tendency to lie almost parallel to the surface are all diagnostic characters. The antennae are white toward the base and much darker toward the tip. In some habitats the larvae possess red eyes that can be quite striking. Under the microscope, Cx. territans superficially resembles Culiseta melanura. The air tube is nearly as long as that of Cs. melanura and both species possess siphonal tufts that form a line that runs directly up the back of the siphon. The comb scales are the easiest character to use to distinguish between these two similar species. Culiseta melanura has broad bar-like comb scales that are unlike those found on any other species. Culex territans has comb scales arranged in a broad patch.


Northern New Jersey

Location: Glen Gardner, Hunterdon Co.

Date : July 21

Habitat : Seepage pool along small stream

Instar : 1st - 4th & Pupae

Southern New Jersey

Location: Goshen, Cape May Co.

Date :August 7

Habitat : Sphagnum Bog

Instar : 1st - 4th & Pupae

IMPORTANCE: Culex territans is a frog feeding mosquito that has no known economic importance. The species shares habitat with a wide variety of amphibians and rarely, if ever, feeds on warm blooded animals. It is possible that the mosquito plays a role in the transfer of arboviruses to cold blooded overwintering hosts but the hypothesis has never been fully documented. Like Wyeomyia smithii, the mosquito is a tiny scientific curiosity that poses no threat to mankind.