Family: Theridiidae, large common spider family also called “cobweb weavers” or “combfooted spiders” Range: Worldwide cosmopolitan areas and coastal United States (Atlantic, Pacific and Gulf). It ranges inland from the Pacific Northwest as far east as Idaho. Habitat: Common “house spider” found in and around buildings, and other structures. Size: Female body length 0.3 inch (8 mm), male 0.23 inch (6 mm).

Photo: Ric Brewer

Description: Resembles the black widow spider with its spherical abdomen but without the distinctive red “hour glass” marking. However, there are vague, flesh-colored spots on the underside that are easily mistaken for the "hourglass." May be reddish to purplish brown in color with or without pale yellowish or whitish markings on the dorsal abdomen. In Seattle, most mature females show no dorsal markings.

Life Span: Females may live up to six years and males for 12-18 months.

Web: The sedentary cobweb weavers construct irregular webs and hang upside down in the center or hide nearby. The comb or bristles on the ends of the fourth pair of legs enable these spiders to throw silk over their prey.

Diet: Chiefly crawling insects, especially isopods (sowbugs, pillbugs), sometimes other spiders.

Interesting Facts:
False black widows are known to prey upon both the black widow in its natural habitat (black widows do not live in the Seattle area) and the hobo spider found in the Seattle area. They almost certainly serve as a very important predator of the hobo in the coastal Pacific Northwest!

These spiders are capable of biting but produce, at most, only minor symptoms like temporary redness and soreness!

Steatoda grossa was the species that bit Peter Parker turning him into “Spiderman” (in the movie). However, the metallic blue color with red-orange markings was painted.