Common American House Spider
Parasteatoda tepidariorum
Theridiidae (Cobweb Spiders), Order Araneae
Physical Description
Rounded, bulbous abdomen with a smaller, compact cephalothorax typical of cobweb spiders, featuring slender legs and a smooth body texture with subtle setae.
Size Estimate
Body length ranges from 5 to 8 mm for females, with a leg span of approximately 15 to 25 mm.
Coloration & Markings
Mottled brown, grey, and whitish patterns with dark chevron markings along the rear portion of the rounded abdomen.
Web Type
Tangle web or cobweb constructed in corners, crevices, or near ceilings, consisting of a messy, three-dimensional mesh of sticky silk.
Eye Arrangement
Eight small eyes arranged in two rows of four, set closely together on a raised ocular tubercle on the cephalothorax.
Leg Characteristics
Slender, moderately long legs featuring subtle darker banding patterns without heavy spination.
Venom & Safety Information
Venom Information
Contains mild neurotoxic venom designed primarily for subduing small insect prey.
Medical Significance
Not medically significant; bites are rare, typically occur only when trapped against the skin, and result in mild, localized irritation.
Safety Recommendations
No special safety measures required; can be safely relocated using a cup and card if found in an unwanted indoor location.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution found worldwide, commonly inhabiting human dwellings, outbuildings, barns, and protected outdoor niches.
Behavior & Temperament
Docile and non-aggressive; hangs upside down in its web, retreating when disturbed and dropping to the ground if threatened.
Diet & Prey
Feeds on a wide range of crawling and flying insects including flies, mosquitoes, ants, and other small spiders caught in its sticky web.
Seasonal Activity
Active year-round indoors, with peak mating and web-building activity occurring during the warmer spring and summer months.
Description
A familiar and harmless household resident, the common house spider builds messy webs in quiet corners to patiently capture nuisance insects.
Key Features
Globular, bulbous abdomen, mottled brown coloration with chevron patterns, and a messy three-dimensional cobweb.
Similar Species
Latrodectus species (Widow spiders), which are distinguished by shiny black bodies and distinct red hourglass or spot markings.
Life Cycle
Females produce brownish, pear-shaped silk egg sacs containing hundreds of eggs, guarding them until spiderlings emerge and disperse via ballooning.
Ecological Importance
Serves as an effective natural pest control agent by significantly reducing indoor populations of flies and mosquitoes.
Conservation Status
Not evaluated by the IUCN, but exceptionally common and widespread with secure population levels globally.
Interesting Facts
These spiders can adjust the tension of individual silk threads in their web to better detect the vibrations of struggling prey.
Photography Tips
Use macro lenses with good side-lighting to highlight the intricate abdominal patterns while maintaining a safe focal distance.
Identified: 2026-09-02T20:47:25.421984