Common House Spider

Parasteatoda tepidariorum, commonly known as the common house spider, belongs to the family Theridiidae, true cobweb weavers. Adults measure 4–8 mm in body length, typically exhibiting mottled brown, grey, or black colorations on a distinctly globose abdomen, often with a subtle white or yellowish chevron pattern. Its lifecycle comprises egg, multiple instars (spiderlings), and adult stages, with females producing up to 17 spherical egg sacs over their 12–24 month lifespan, each containing 100–400 eggs, often suspended within the web. Development from egg to adult takes approximately 3–4 months under optimal indoor conditions (20–25°C, 60–80% RH), with males generally being smaller and having shorter lifespans. Distinguishing features include proportionally long, slender legs, the lack of a strong carapace, and the characteristic messy, three-dimensional cobweb.

This species exhibits primarily nocturnal activity, constructing and maintaining its irregular, tangled three-dimensional cobwebs in undisturbed areas. Individual spiders are solitary, with no complex social structures, and communicate primarily through tactile cues on the web and potentially through contact pheromones during mating. Their feeding ecology is generalist and opportunistic, encompassing a wide range of crawling and flying insects such as flies, mosquitoes, ants, and even other spiders, captured by entanglement in the non-sticky portions of their web followed by venom injection. While capable of biting, P. tepidariorum is non-aggressive; bites to humans are rare, usually occurring only when the spider is severely provoked or accidentally pressed against skin, delivering a venom that causes only localized, mild irritation akin to a bee sting, posing no significant public health risk.