Common house spider

Description:

They are generally dull in appearance, with patterns consisting of brown shades for coloration, often giving a vague spotted appearance that is particularly noticeable on the legs. Their average body size is a quarter-inch (6 mm) long. These traits combined allow the spiders to blend into the background and escape notice. Like some other species of the family Theridiidae, P. tepidariorum shares a body shape and size that makes it similar to widow spiders, which have venom that is classified as potentially dangerous. A male and female often share the same web for longer periods, and several females often build their webs in close proximity. However, several females will fight each other on an encounter. This species can live for more than a year after reaching maturity. Each egg sac contains from 100 to more than 400 eggs, with a single female producing up to 17 egg sacs. The hatchlings remain in the mother's web for several days. American house spiders usually feed on household pests such as flies, mosquitoes, ants and wasps. They can randomly attack grasshoppers, butterflies, cockroaches or other spiders depending on their size. If the prey is too agile, the spider will try shooting web at it from a distance before pulling the thread toward itself. Bigger females can also attract baby skinks inside their web by leaving fly remains hanging in it. Once its food dries out, the spider usually drops it to the floor in order to free some space in its web, instead of destroying and rebuilding it or changing its location. Three spider species usually prey upon them: the pirate spiders of the genus Mimetus (Mimetidae), as well as two jumping spider species - Phidippus variegatus and Metacyrba undata. The latter one also often falls prey to its own food when it gets trapped in the tangling web after missing the jump on its target. The assassin bug Stenolemus lanipes (Emesinae) feeds apparently exclusively on spiderlings of this species, but can also become prey of the adult spider.

Habitat:

House wall.

Notes:

Photos 1-4 are of the female that was about 5 mm long. The male (photo 5) was about one third of her size.