Common House Spider
Parasteatoda tepidariorum
Theridiidae (Cobweb Spiders), Order Araneae
Physical Description
The Common House Spider features a bulbous, nearly spherical abdomen that is noticeably larger than its cephalothorax. Females are typically larger and rounder, while males have a narrower abdomen and longer legs. The body surface is covered in fine hairs, and the overall silhouette is compact yet rounded.
Size Estimate
Body length ranges from 5 to 8 mm for females and slightly smaller for males, with a leg span of approximately 1.5 to 2.5 cm. This represents a typical adult specimen.
Coloration & Markings
Base coloration varies from yellowish-brown to dark brown or grey. The abdomen often features mottled patterns, chevron markings, or dark spots, sometimes with light borders. The legs are typically yellowish with distinct dark brown or blackish rings.
Web Type
Builds an irregular, three-dimensional tangle web commonly known as a cobweb. These webs are constructed in dark, sheltered corners, under furniture, or near human structures, consisting of sticky silk threads that trap crawling and flying insects.
Eye Arrangement
Eight eyes arranged in two parallel rows of four. The lateral eyes are typically touching or very close together, while the median eyes are larger, which is characteristic of the Theridiidae family.
Leg Characteristics
Legs are moderately long and thin, featuring visible dark banding. The fourth pair of legs possesses a comb-like row of serrated bristles (the comb) used to pull and wrap silk around prey.
Venom & Safety Information
Venom Information
Possesses neurotoxic venom designed specifically for small invertebrate prey. Their venom is very mild and poses no significant threat to humans or larger domestic animals.
Medical Significance
Harmless to humans. Bites are extremely rare, typically only occurring if the spider is squeezed directly against the skin. Symptoms are minimal, usually limited to minor localized redness or slight temporary discomfort.
Safety Recommendations
No special safety measures are required. If removal is desired, gently guide the spider into a cup using a piece of paper and release it outdoors.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution found worldwide in association with human habitations. Prefers dark, undisturbed indoor areas such as basements, attics, garages, and corners of rooms, as well as sheltered outdoor niches.
Behavior & Temperament
Docile and non-aggressive. They spend most of their time hanging upside down in their cobwebs, waiting for prey. When disturbed, they typically drop to the ground or retreat quickly to a nearby crevice.
Diet & Prey
Feeds on a wide variety of household insects and arthropods, including flies, mosquitoes, ants, beetles, and other spiders. Prey is subdued with venom and wrapped in silk before consumption.
Seasonal Activity
Active year-round indoors, with peak mating and web-building activity occurring during the warmer spring and summer months.
Description
The Common House Spider is an inconspicuous yet beneficial neighbor found in homes across the globe. Known for constructing untidy cobwebs in quiet corners, this master pest controller quietly helps keep household insect populations in check while remaining entirely harmless to humans.
Key Features
Rounded, bulbous abdomen; irregular cobweb construction; mottled brown and grey coloration with banded legs; characteristic comb-like bristles on the fourth pair of legs.
Similar Species
Can be confused with cellar spiders (Pholcidae) or widow spiders (Latrodectus). Cellar spiders have much longer, thread-like legs, while widow spiders feature smoother, glossier black bodies with distinct red markings.
Life Cycle
Females construct brownish, pear-shaped silk egg sacs containing dozens to hundreds of eggs, often hanging several sacs in their web. Spiderlings disperse via ballooning after hatching. Lifespan for females can reach over a year.
Ecological Importance
Serves as an effective natural pest control agent inside human dwellings, significantly reducing populations of nuisance and disease-carrying insects.
Conservation Status
Not evaluated by the IUCN, but populations are abundant, widespread, and entirely secure due to their close association with human habitats.
Interesting Facts
Despite their messy reputation, these spiders meticulously clean their webs and consume old silk to recycle proteins. They are one of the most successful synanthropic spider species globally.
Photography Tips
Use macro photography with diffused lighting to capture the fine details of the abdominal patterns and the characteristic leg banding. Photographing from the side provides the best view of the body proportions.
User Notes
In a web
Identified: 2026-08-04T00:31:13.764573