Common American House Spider, Cobweb Spider
Uncertain (Likely Parasteatoda tepidariorum or similar Theridiidae species)
Theridiidae (Cobweb Spiders), Order Araneae. Key family characteristics include a rounded abdomen, comb-like setae on the fourth tarsus used for flinging silk, and building irregular, three-dimensional tangle webs.
Physical Description
The spider has a bulbous, rounded abdomen typical of comb-footed spiders, connected to a smaller cephalothorax. The body texture appears slightly glossy with fine setae.
Size Estimate
The visible specimen is partially obscured and out of focus, but typical adult body length for a house spider ranges from 5 to 8 millimeters with a leg span around 15 to 25 millimeters.
Coloration & Markings
Appears brownish with mottled or chevron-like darker patterns along the dorsal abdomen, typical of many common household cobweb spiders.
Web Type
Irregular tangle web or cobweb, constructed in corners, dark recesses, and near ground clutter. Composed of sticky, haphazard threads designed to catch walking or flying insects.
Eye Arrangement
Eight small eyes arranged in two rows of four, typical of the family Theridiidae, set on dark tubercles on the cephalothorax.
Leg Characteristics
Long, slender legs with faint banding. The fourth pair possesses a comb-like row of bristles used to pull silk from the spinnerets.
Venom & Safety Information
Venom Information
Contains neurotoxic components typical of cobweb spiders, but the venom is generally weak and poses no significant threat to humans.
Medical Significance
Harmless to humans. Bites are extremely rare, usually only occurring if the spider is trapped directly against the skin. Symptoms are typically minor localized pain and redness.
Safety Recommendations
No special precautions needed. 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, frequently found indoors in human dwellings, garages, basements, and sheds, as well as outdoors in sheltered dark crevices.
Behavior & Temperament
Docile, sedentary, and non-aggressive. They spend most of their time hanging upside down in the center of their web, retreating when disturbed.
Diet & Prey
Generalist insectivore feeding on household pests such as flies, mosquitoes, ants, beetles, and other spiders.
Seasonal Activity
Active year-round indoors due to climate-controlled environments, with increased mating activity during warmer spring and autumn months.
Description
A common resident of human habitations, this cobweb spider plays a quiet yet effective role in natural pest control. Living inconspicuously in dark corners, it builds tangled webs to intercept unwary insects.
Key Features
Bulbous rounded abdomen, tangled web construction, long spindly legs, and habit of hanging upside down in a messy web.
Similar Species
Cellar Spiders (Pholcidae) which have much longer legs and lack a bulbous abdomen; Steatoda species (False Widows) which tend to have glossier, darker, more robust bodies.
Life Cycle
Females produce brownish, pear-shaped silk egg sacs containing hundreds of eggs. Spiderlings disperse via ballooning after hatching, undergoing multiple molts to reach maturity.
Ecological Importance
Acts as an effective biological control agent inside buildings and gardens by reducing populations of stinging or disease-carrying insects.
Conservation Status
Not evaluated by the IUCN, highly abundant and widespread globally, thriving alongside human development.
Interesting Facts
House spiders can survive long periods without food or water by retreating into deep cracks, and females may guard multiple egg sacs in the same web.
Photography Tips
Use macro settings with adequate lighting, as indoor settings are often dim. Focus on the dorsal pattern of the abdomen and eye arrangement if close enough.
Identified: 2026-07-31T00:42:17.935289