Common House Spider

Theridiidae—Cobweb Weavers

(Parasteatoda tepidariorum)

Parasteatoda tepidariorum is a cosmopolitan spider that is widely distributed throughout most of the world. It is extremely common in barns and houses, where it constructs webs in the corners of walls, floor joists, and windows. The common house spider may also be found outside under objects such as rocks and boards, as well as beneath bridges and similar structures. In homes, it is most often encountered in damp areas such as basements and crawl spaces. Because this spider frequently abandons its web to build a new one nearby, it can produce many webs in a short period of time. This behavior causes homeowners much grief.

Description

Common house spider web and egg cases. Photo by Steven Jacobs, Penn State Extension

The common house spider female is 5 to 6 millimeters in length with a yellowish-brown carapace and a dirty-white to brown abdomen with gray chevrons. The legs are yellow, with darker rings at the end of each segment. Some individuals have a triangular black spot on the top of the abdomen. The male is 3.8 to 4.7 millimeters in length with orange legs.

Life History

Males and females can be found at any time of year, and there are reports of the spiders living for a year or more after maturing. The male and female will coexist in the web and mate repeatedly. The egg sacs are brown and ovoid with tough, papery covers and can be 6 to 9 millimeters in diameter. A female may deposit twelve or more egg sacs over her lifetime, each containing 140 to 380 eggs.

Medical Importance

Parasteatoda tepidariorum is not regarded as a medically important species. In fact, given this spider's tendency to populate houses, plus the paucity of reported bites in the literature, it is apparent that the house spider does not often bite people. The few recorded and verified bites were accompanied by pain (increasing for one hour), red mark, or redness, with the duration of pain being 4 to 24 hours.

Reference

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Levi, H. W. 1959. "The Spider Genus Latrodectus (Araneae, Theridiidae)." Trans. Amer. Microscopical Soc. 78(1): 7–43.

Long, D., R. Snetsinger, and K. F. Helm. 1995. "Localized Pruritic Rash Due to Recurrent Spider Bites." J. Geriatr. Dermatol. 3(6): 186–190.

McKeown, N., R. S. Vetter, and R. G. Hendrickson. 2014. "Verified spider bites in Oregon (USA) with the intent to assess hobo spider venom toxicity." Toxicon 84: 51–55.