Steatoda grossa

From Wikipedia, the free encyclopedia

Steatoda grossa

Scientific classification

Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Arachnida
Order:	Araneae
Family:	Theridiidae
Genus:	Steatoda
Species:	S. grossa

Binomial name

Steatoda grossa
(C. L. Koch, 1838)

Steatoda grossa, commonly known as the cupboard spider, the dark comb-footed spider, the brown house spider (in Australia), or the false black widow (though several other species are known by these names), is a common species of spider in the genus Steatoda. As one of this spider's common name indicates, the spider superficially resembles, and is frequently confused for, the black widow and other venomous spiders in the genus Latrodectus.

1 Description
2 Habitat and range
3 Medical significance
4 Trivia
5 External links

[edit] Description

Like black widows, the female S. grossa is 6-10.5 mm in length, and dark colored, with a round, bulbous abdomen. Typical coloration ranges from purplish-brown to black, with light-colored markings. Unlike black widows, red-backs, and other Latrodectus species, the S. grossa does not have a bright red hourglass pattern or any other bright markings. Like many spiders, the male is smaller; it measures 4.1-7.20mm in length, and is thinner than the female. The two sexes are colored similarly.

Female S. grossa spiders can live up to six years; the typical lifespan for the male is 1-1.5 years. Males die shortly after mating.

[edit] Habitat and range

In common with other members of the Theridiidae family, S. grossa constructs a cobweb, i.e., an irregular tangle of sticky silken fibers. As with other web-weavers, these spiders have very poor eyesight and depend mostly on vibrations reaching them through their webs to orient themselves to prey or warn them of larger animals that could injure or kill them. They are not aggressive, and most injuries to humans are due to defensive bites delivered when a spider gets unintentionally squeezed or pinched somehow. It is possible that some bites may result when a spider mistakes a finger thrust into its web for its normal prey, but ordinarily intrusion by any large creature will cause these spiders to flee.

S. grossa is a cosmopolitan species, and is found in many parts of the world, including all three coasts in North America, in Australia and New Zealand, and in Europe.

A related species, commonly found in North America, is Steatoda borealis. This spider is similar to S. grossa in shape, but slightly smaller, and is generally found in colder climates. This spider can be identified by colored markings on the dorsal side of its abdomen, rather than on the ventral side.

[edit] Medical significance

The bite of S. grossa is known to be medically significant in humans, however without any long-lasting effects. Symptoms of bites include blistering at the site of the bite, and/or a general malaise lasting for several days. The Latrodectus antivenin has been shown to be effective at treating bites from Steatoda grossa, after it was mistakenly administered to a S. grossa bite victim who was erroneously believed to have bitten by the far more dangerous redback. These spiders are known for preying on true black widows, redback spiders and hobo spiders, in areas where the species share a common range.

[edit] Trivia

A specimen of S. grossa, painted with blue and red stripes, was used as the spider which bit Peter Parker in the Sam Raimi-directed Spider-Man film, released in 2002.