Dolomedes sulfureus — identification & habitat

Dolomedes sulfureus is a large East Asian fishing spider that comes in yellowish, brown, and dark forms, sometimes with pale side stripes. In its native range it hunts on vegetation and the ground, including places away from open water.

Appearance

Appearance: Adults are large, with a body about 0.5–1 in (12–26 mm) long; males are usually smaller. The long, sturdy legs and highly variable colors make pattern alone unreliable for identification.

Look-alikes

dark fishing spiderDolomedes tenebrosus

A large brown fishing spider photographed in the eastern United States could be a dark fishing spider. Color alone cannot safely separate it from this East Asian species; a clear location is the first clue.

Why they get mixed upBoth are large, variably brown fishing spiders that may be found away from open water.

Where it lives

Typical habitats: low vegetation
damp ground
streamside vegetation
Range: Its documented range is the Russian Far East, China, Korea, and Japan.
Preferred conditions: It often hunts on vegetation and can occur away from open water, although it is also found in moist places and near streams.

Behavior

Diet: It is an active predator of insects. Korean records also document tadpoles and small fish as occasional prey.
Activity: It does not make a prey-catching web. In Japan, it has been observed waiting on leaves and grabbing insects that land nearby.

Life cycle

Breeding season: South Korean records place adult activity and mating mainly from June through September.
Nest: The female carries and guards a round beneath her mouthparts.
Incubation: South Korean records report hatching after about one to two weeks in the egg sac, with spiderlings emerging roughly two weeks later.

Name and classification

Varieties and forms: Plain yellow-brown, dark brown, mottled, and pale-striped individuals are color forms of the same species.

Conservation

IUCN Red List: NENot EvaluatedNot yet assessed

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