House Spider

The common house spider, Parasteatoda tepidariorum, belongs to the family Theridiidae, known as the cobweb or tangle-web spiders. It is one of the most widespread synanthropic spiders, meaning it thrives in close association with human buildings across much of the world.

This species is notable for constructing loose, irregular three-dimensional webs rather than the neat orb webs many people associate with spiders, and for its habit of remaining in the same web for extended periods while it captures passing insects.

Ecologically, house spiders act as beneficial indoor predators, helping to naturally reduce populations of flies, mosquitoes, and other small insects that wander into their webs.

• Rounded, bulbous abdomen, typically brown to gray with darker mottled chevron-like markings.
• Long, thin, banded legs relative to body size.
• Eight eyes arranged in two rows, though eye pattern is rarely visible without close inspection.
• Builds messy, irregular tangle webs rather than symmetrical orb webs.
• Lookalikes: often confused with widow spiders, but house spiders have mottled brown patterning rather than a solid black body with a red hourglass marking.

House spiders are found across North America and many other regions worldwide, almost always in and around structures such as homes, garages, barns, and sheds. They favor undisturbed corners, window frames, and ceiling junctions, remaining active year-round indoors where temperatures stay stable.

This spider builds a tangled, irregular web and waits at its center or in a nearby retreat for prey to become ensnared, then quickly wraps and subdues it with silk. Its diet consists of small flying and crawling insects that blunder into the web. House spiders are generally sedentary, rebuilding or repairing the same web site over long periods rather than relocating frequently.

House spiders undergo simple development without metamorphosis, hatching from eggs as miniature versions of adults and growing through a series of molts. Females produce round, papery egg sacs that are guarded within or near the web and can contain dozens of eggs. Multiple generations can occur per year in heated indoor environments, with adults capable of living for a year or more.