Dolomedes tenebrosus

Hentz, 1844

Dark Fishing Spider

Dolomedes tenebrosus, commonly known as the dark fishing spider, is a large nursery web spider native to North America. Despite its , this is primarily arboreal and frequently found in wooded far from water, distinguishing it from more aquatic . Females are notably larger than males and exhibit sexual during mating. The species is capable of biting humans but typically flees when disturbed.

Dolomedes tenebrosus by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.

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Dolomedes tenebrosus by (c) Zachary Dankowicz, some rights reserved (CC BY), uploaded by Zachary Dankowicz. Used under a CC-BY license.

Pronunciation

How to pronounce Dolomedes tenebrosus: /dɔloʊˈmiːdiːz tɛnəˈbroʊsəs/

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Identification

Distinguished from other Dolomedes by interrupted white borders behind the W-shaped abdominal markings. Females measure 15–26 mm in body length (excluding legs), males 7–13 mm; leg span ranges 50–90 mm. Coloration is pale to dark brown with chevron markers on the and lighter stripes on the legs. Legs are banded with brown/black annulations on and reddish-brown/black annulations on tibiae. Similar to D. scriptus in general appearance.

Images

Habitat

Wooded areas, particularly forests with mature trees. Frequently found under loose bark, in tree holes, and within rock crevices. Commonly enters homes in wooded locations. Unlike many fishing spiders, this is typically found far from water in dry, arboreal settings.

Distribution

United States and Canada. Recorded from provinces including Manitoba and Ontario.

Life Cycle

Hibernates as an ( instar) under loose bark or stones.

Behavior

Females practice sexual on males during copulation; male consumption by the female has been observed to increase offspring . Typically flees at the slightest movement when encountered. activity pattern observed.

Ecological Role

Serves as prey for spider wasps, including Priocnemis minorata.

Human Relevance

Capable of biting humans, though bites are typically no more severe than or stings. Individuals sensitive to spider venom may be at increased risk. Frequently enters homes in wooded areas, where encounters with humans are common.

Similar Taxa

Dolomedes scriptusSimilar abdominal patterning and general appearance; distinguished by different border patterns on abdominal markings
Wolf spiders (Lycosidae)Similar robust build and arrangement; distinguished by preference (arboreal vs. ground-dwelling) and lack of burrowing

Misconceptions

Despite the 'fishing spider,' this is better described as tree-dwelling and is frequently encountered far from aquatic . The name reflects phylogenetic affinity rather than ecological habit in this case.