House Spider

The common name reflects the fact that this is usually the spider most often encountered indoors. It is a nuisance pest, probably more because of its webs than the spider itself. This spider is found worldwide and is common throughout the United States and Canada.

Recognition

Adult female body length is about 3/16-5/16 inch including an almost spherical abdomen. Male body length is about 1/8-3/16 inch including and elongated abdomen. Color highly variable with carapace yellowish brown; abdomen dirty white with a few dark spots to almost black, with several dark stripes meeting at angle medially above tip of abdomen; legs orange in male but yellow in female, with dusky ring at end of each segment. With eight eyes, two lateral pairs almost touching. Last tarsal segment of fourth pair of legs with row of serrated bristles on venter; all tarsi with three claws each.

Habits

The house spider randomly selects its web sites. If a web does not yield prey it is abandoned, another site is selected, and a new web built. Eventually, successful webs are constructed where air currents bring in prey. Survival is low in modern homes with low humidity and few insects, higher in garages, sheds, barns, warehouses, etc. because of more prey and generally higher humidity, and highest outdoors in protected places.

Inside structures, house spiders most likely are found in upper corners, under furniture, in closets, angles of window frames, basements, garages, and crawl spaces. In warehouses, they are common in corners near doors that stay open. Outside, they are often around windows and under eaves, especially near light sources, which attract prey.