Parasteatoda

Parasteatoda is a genus of spiders in the family Theridiidae, commonly known as cobweb spiders. Members are small to medium-sized with rounded abdomens and typically brown, gray, or reddish coloring that may display various patterns. They construct tangled, irregular cobwebs in sheltered locations such as corners of rooms, basements, sheds, and under eaves.

The best-known species is Parasteatoda tepidariorum, the common house spider, which has a cosmopolitan distribution and is frequently found in human structures. Another widely distributed species is Parasteatoda triangulosa, the triangulate cobweb spider, recognizable by triangular patterns on the abdomen. The genus includes several other species with overlapping ranges in warm to temperate regions.

Parasteatoda spiders are opportunistic predators that feed on small insects caught in their irregular webs. They are generally not aggressive toward humans, and bites are uncommon and usually mild when they occur. Their presence can help reduce indoor pest populations, though they may be considered nuisances when they inhabit living spaces.

Taxonomically, Parasteatoda lies within Theridiidae, a family known for diverse cobweb-building spiders. The genus comprises multiple species described worldwide, with P. tepidariorum and P. triangulosa among the most commonly encountered. As with other spiders that inhabit human-made structures, Parasteatoda species show adaptability to a variety of microhabitats.