Common House Spider, American House Spider
Parasteatoda tepidariorum (or similar Theridiidae species)
Theridiidae (Cobweb Spiders), Order Araneae. Characterized by a comb-like row of setae on the fourth tarsus used to pull silk from spinnerets.
Physical Description
Bulbous, rounded abdomen with a cephalothorax that is considerably smaller and narrower. The body texture appears smooth to slightly hairy, typical of comb-footed spiders.
Size Estimate
Small to medium, approximately 5mm to 8mm in body length, with a leg span around 15mm to 25mm based on standard residential observations.
Coloration & Markings
Mottled brown, grey, and cream coloration with chevron patterns or darker spots along the dorsal side of the abdomen to provide camouflage against walls and corners.
Web Type
Irregular tangle web (cobweb) constructed in corners, crevices, and architectural features like the shingle siding shown in the image.
Eye Arrangement
Eight eyes arranged in two slightly curved rows of four, with lateral eyes often touching or closely grouped.
Leg Characteristics
Slender, moderately long legs with faint dark banding, lacking heavy spination but featuring the diagnostic serrated comb on the rear tarsi.
Venom & Safety Information
Venom Information
Neurotoxic venom specialized for subduing small insect prey; poses no significant threat to humans.
Medical Significance
Harmless to humans. Bites are extremely rare, typically only occurring if the spider is directly trapped against the skin, resulting in minor localized discomfort similar to a mild mosquito bite.
Safety Recommendations
No special safety measures 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; highly synanthropic, commonly found in and around human habitations, basements, sheds, and exterior walls.
Behavior & Temperament
Timid and non-aggressive; spends most of its time motionless in its web, retreating when disturbed rather than striking.
Diet & Prey
Generalist insectivore feeding on crawling and flying household pests including flies, mosquitoes, ants, and other small spiders.
Seasonal Activity
Active year-round indoors, with peak visibility and outdoor web construction during the warmer spring and summer months.
Description
A familiar and harmless tenant of human structures, this small cobweb spider quietly spins its disorderly web in neglected corners and crevices, acting as a natural pest control agent.
Key Features
Bulbous, rounded abdomen, mottled brown and grey coloration, and an irregular cobweb constructed in a structural corner or crevice.
Similar Species
Steatoda grossa (False Black Widow), which is darker, shinier, and more robustly built.
Life Cycle
Females produce several brownish, pear-shaped silk egg sacs suspended within the web. Spiderlings hatch and disperse via ballooning or crawling short distances.
Ecological Importance
Serves as an effective biological control agent by consuming large numbers of nuisance and disease-vector insects around human dwellings.
Conservation Status
Not evaluated by the IUCN, but populations are abundant, secure, and thriving globally alongside human infrastructure.
Interesting Facts
Common house spiders can adjust the tension of their web threads to efficiently detect the vibrations of trapped prey.
Photography Tips
Use macro settings and adequate lighting, focusing on the abdomen and leg patterns while maintaining a steady hand against architectural surfaces.
Identified: 2026-08-01T21:23:48.173670