Common House Spider, American House Spider
Parasteatoda tepidariorum
Theridiidae (Cobweb Spiders), Order Araneae
Physical Description
The spider has a bulbous, globular abdomen that is noticeably larger than its cephalothorax, typical of cobweb spiders. The body is relatively smooth with sparse, fine hairs. Females are larger and more round-bodied, while males are slender with longer legs.
Size Estimate
Body length typically ranges from 5 to 8 mm for females and 3.8 to 5 mm for males, with a leg span of roughly 2 to 3 cm.
Coloration & Markings
Coloration ranges from yellowish-brown to dark brown or grayish. The abdomen often features darker chevrons, mottling, or spots, sometimes with light triangular markings bordered in dark brown.
Web Type
Builds an irregular, three-dimensional tangle web commonly known as a cobweb, constructed in dark corners, under furniture, or around human dwellings.
Eye Arrangement
Consists of eight small eyes arranged in two rows of four, typical of the Theridiidae family, with lateral eyes often touching.
Leg Characteristics
Legs are long and slender, typically yellowish-brown with faint dark banding or rings, lacking heavy spination but equipped with combs on the tarsi for wrapping prey.
Venom & Safety Information
Venom Information
Possesses neurotoxic venom designed for subduing small insect prey; it is generally weak and poses no serious threat to humans.
Medical Significance
Harmless to humans. Bites are extremely rare, usually only occurring if the spider is trapped directly against the skin, resulting in minor, localized pain and redness that resolves quickly.
Safety Recommendations
No special safety measures required. If relocation is desired, gently guide the spider into a cup using a piece of card and release it outdoors.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide; commonly found indoors in houses, basements, sheds, and garages, as well as outdoors in sheltered crevices, bark, and rock piles.
Behavior & Temperament
Non-aggressive and very timid. They hang upside down in their webs and retreat rapidly when disturbed, dropping to the ground or fleeing.
Diet & Prey
Feeds primarily on crawling and flying household pests including flies, mosquitoes, ants, beetles, and other small spiders.
Seasonal Activity
Active year-round indoors due to climate control, with increased visibility and mating activity peaking during the warmer spring and summer months.
Description
The common house spider is a familiar and harmless neighbor found in homes across the globe. With its characteristic bulbous abdomen and messy web tucked away in ceiling corners, it serves as an efficient and silent pest controller, quietly managing populations of household insects.
Key Features
Bulbous, rounded abdomen; irregular tangle cobweb; slender, banded legs; yellowish-brown to dark brown coloration with chevron patterns.
Similar Species
Steatoda grossa (False Black Widow), which has a more shiny, leather-like, and darker purple-brown abdomen without clear chevron patterns.
Life Cycle
Females produce pear-shaped silk egg sacs containing up to several hundred eggs, hanging them within the web. Spiderlings disperse via ballooning after hatching, undergoing several molts to reach maturity.
Ecological Importance
Acts as an effective natural pest control agent inside human structures and gardens, significantly reducing populations of nuisance and disease-carrying insects.
Conservation Status
Not evaluated by the IUCN, but populations are extremely abundant, stable, and widespread globally.
Interesting Facts
Despite living in close proximity to humans for centuries, they rarely bite and prefer to play dead or retreat when threatened. A single female can produce multiple egg sacs over her lifespan.
Photography Tips
Use macro lenses or smartphone macro attachments with good lighting. Photograph from a side angle to clearly capture the abdominal pattern and body proportions.
Identified: 2026-08-30T14:51:31.356876