Common House Spider
Parasteatoda tepidariorum
Theridiidae (Cobweb Spiders), Order Araneae. Key family characteristics include a rounded abdomen, comb-like setae on the fourth tarsus used to pull silk over prey, and building irregular tangle webs.
Physical Description
The spider has a globose, bulbous abdomen that is notably larger than the cephalothorax, typical of cobweb spiders. The body texture is smooth to sparsely bristled, and females are visibly larger and more rounded than males.
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. The specimen appears to be an adult or sub-adult.
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 triangular or pale patches.
Web Type
Builds an irregular three-dimensional tangle web, commonly known as a cobweb, constructed in dark, protected corners of ceilings, walls, or furniture.
Eye Arrangement
Eight eyes arranged in two parallel rows of four, typical of the Theridiidae family, with lateral eyes often touching or closely grouped.
Leg Characteristics
Long, slender legs with faint dark banding. The legs lack heavy spination but possess specialized comb-like structures on the hind tarsi for wrapping prey in silk.
Venom & Safety Information
Venom Information
Neurotoxic venom specialized for subduing small insect prey. It is generally harmless to humans and large pets.
Medical Significance
Not medically significant. Bites are extremely rare, usually occurring only when trapped against human skin, and result in mild, localized irritation similar to a mosquito bite.
Safety Recommendations
No special safety measures are required. If relocation is desired, gently guide the spider into a container using a piece of paper and release it outdoors.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution globally. Found almost exclusively indoors and in sheltered outdoor structural locations like sheds, garages, eaves, and window frames.
Behavior & Temperament
Non-aggressive and very timid. They spend most of their time hanging upside down in their webs, retreating rapidly when disturbed.
Diet & Prey
Feeds on a wide variety of household insects including flies, mosquitoes, ants, beetles, and other small spiders caught in its web.
Seasonal Activity
Active year-round indoors due to climate-controlled environments, with increased wandering and mating activity typically observed in late summer and autumn.
Description
The Common House Spider is a familiar and harmless indoor resident. With its bulbous abdomen and preference for quiet corners, it acts as a natural pest control agent inside homes.
Key Features
Rounded, bulbous abdomen, mottled brown coloration, slender legs with faint banding, and construction of messy tangle webs in corners.
Similar Species
Can be confused with cellar spiders (Pholcidae), which have much longer, thread-like legs, or occasionally with medically significant spiders like Steatoda grossa (False Widow), which has a glossier, more purplish-black body.
Life Cycle
Females produce several brownish, pear-shaped silk egg sacs containing up to several hundred eggs. Spiderlings disperse shortly after hatching. Lifespan can exceed one year for females.
Ecological Importance
Serves as an effective biological control agent by consuming large numbers of nuisance and disease-vector insects inside human habitations.
Conservation Status
Not evaluated by the IUCN, but highly abundant and secure globally due to its close association with human habitations.
Interesting Facts
Common house spiders are known to mate multiple times, and females will often maintain the same web site for months, adding layers of silk over time.
Photography Tips
Use macro lenses or smartphone macro modes with adequate lighting. Take photos from the side to capture the profile of the rounded abdomen and leg banding.
Identified: 2026-09-07T09:22:37.261750