Common House Spider, American House Spider
Parasteatoda tepidariorum
Theridiidae (Cobweb Spiders), Order Araneae
Physical Description
A small, globular spider with a high, rounded abdomen that often tapers to a point at the rear. The cephalothorax is relatively small compared to the bulbous abdomen. Texture is generally smooth but covered in very fine hairs.
Size Estimate
Typically 5-8 mm for females (body length); males are smaller at 3-5 mm. Leg span reaches approximately 20-30 mm. This specimen appears to be an adult or sub-adult based on body proportions.
Coloration & Markings
Highly variable, usually a mottled mix of dull brown, tan, and grey. Often features a distinctive 'V' or 'U' shaped dark marking on the abdomen and chevrons or spotting on the sides. Legs are typically pale yellow or tan with dark banding at the joints.
Web Type
Builds a messy, irregular tangle web (cobweb). These are usually located in corners, under furniture, or behind shutters. The web includes a dense 'retreat' area where the spider hides during the day.
Eye Arrangement
Eight small eyes arranged in two rows of four. The anterior median eyes are often the darkest, used for basic light and motion detection in their tangled webs.
Leg Characteristics
Long, slender legs. The first pair is the longest, followed by the fourth. The legs exhibit distinct dark annulations (banding). They possess 'comb-feet' (serrated bristles) on the fourth tarsi used to throw silk over prey.
Venom & Safety Information
Venom Information
Contains neurotoxic proteins used to paralyze insects. However, the venom is not considered potent or dangerous to humans due to the small quantity and the spider's inability to easily pierce human skin.
Medical Significance
Harmless to humans. Bites are rare and usually only occur if the spider is squeezed. Symptoms are typically limited to minor localized redness, itching, or slight swelling similar to a bee sting. No special treatment is required.
Safety Recommendations
No action is necessary for safety. To remove, simply use a broom or vacuum to clear the web. If relocation is desired, use a cup and a piece of paper to catch the spider and move it to a garage or shed.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution; found worldwide in association with human structures. Prefers dark, humid areas such as basements, crawlspaces, barns, and the corners of ceilings.
Behavior & Temperament
Extremely docile and non-aggressive. They are sedentary hunters that wait in their webs for prey to stumble into the sticky silk. If disturbed, they usually retreat to a corner or drop to the floor and play dead (thanatosis).
Diet & Prey
Generalized insectivore. Consumes flies, mosquitoes, ants, and occasionally other spiders or beetles much larger than themselves by using their comb-feet to wrap prey in silk quickly.
Seasonal Activity
Active year-round in temperature-controlled indoor environments. In natural settings, they are most active from late spring through autumn, with mating peaks in mid-summer.
Description
The quintessential 'cobweb spider' found in homes globally. While their messy webs can be a nuisance to cleaners, these spiders are master pest controllers, quietly capturing nuisances like flies and mosquitoes in the dark corners of our dwellings.
Key Features
Globular abdomen with mottled brown/tan patterns, long banded legs, pear-shaped brown egg sacs, and the construction of irregular tangle webs in structural corners.
Similar Species
May be confused with the Brown Widow (Latrodectus geometricus), but lacks the bright orange/red hourglass. Also similar to Steatoda species (False Widows), which usually have darker, glossier abdomens.
Life Cycle
Females produce several brownish, pear-shaped, papery egg sacs throughout the year. One sac can contain 100-400 eggs. Spiderlings disperse via ballooning. Lifespan is typically about one year.
Ecological Importance
Major household predator of indoor pests. They play a significant role in reducing populations of disease-carrying insects like houseflies and mosquitoes within human environments.
Conservation Status
Not listed by IUCN; extremely common and widespread. Populations are stable and benefit from human urbanization.
Interesting Facts
They are one of the few spiders that are somewhat social as spiderlings, sharing a web for a short time. They are also known to steal prey from other spiders' webs (kleptoparasitism).
Photography Tips
Lighting is key as they often hide in dark corners. Use a macro lens or phone macro mode to capture the banding on the legs and the mottled pattern on the abdomen for positive identification.
Identified: 2026-06-01T00:25:20.402206