A Guide to Common House Spiders in Virginia Homes

The Common House Spider of Virginia

The common house spider (Parasteatoda tepidariorum) is frequently found in and around homes across Virginia. While most spiders play important roles in controlling pests and maintaining the balance of nature, the sudden appearance of spiders in living spaces can startle homeowners. Understanding the habits and traits of this uninvited eight-legged guest can help Virginia residents coexist comfortably with these small spiders.

Physical Description

The common house spider is a small to medium-sized spider, measuring about 4 to 10 millimeters in body length as adults. Their bodies are oval-shaped with a vaguely triangular outline when viewed from above. They have eight eyes arranged in two rectangular rows of four. The body color can range from almost white or tan to a dark brown or grey. The abdomen often has darker mottling or a faint pattern of checkering or stripes. They have eight legs covered in short hairs and small spines. The legs tend to be the same color as the body.

Behaviors

Common house spiders construct messy-looking webs in secluded spot inside homes, typically in corners, crevices, under furniture, in basements, garages, sheds and outbuildings. The strands that anchor the web to various surfaces often extend for several feet, enveloping a large area, but the central part of the web may be quite small. These spiders usually remain hidden within thick webbing during the day and emerge at night to wait near the edges of the web for prey to become stuck. They quickly swarm over trapped insects, using their fangs to inject venom that kills or immobilizes them. They then wrap the prey in silk.

This species tends to thrive indoors because human dwellings provide refuge from predators, mild temperatures, and easy access insect prey attracted to artificial lighting. The messy webs also help camouflage the spider from predators who hunt by sight. Outdoors, common house spiders may build similarly large, disorganized webs under rocks, wood piles, dense vegetation and similar protected locations.

Bite Risk to Humans and Pets

Although they do possess venom like most spiders, common house spiders rarely bite humans. When bites do occur, they result in temporary mild pain and very minor swelling similar to a mosquito bite. These spiders tend to be quite shy and docile. They will often flee from threatening motions and vibrations caused by nearby humans or sudden shadows. The messy web provides them with an early warning system and plenty of room to retreat from perceived threats. Even if carefully picked up by a human, bites almost never occur.

Population Control

The common house spider plays an important role helping to control populations of flies, moths, roaches, silverfish and other household pests that stray into their webs. A single spider may consume dozens of insects per week. Their management does not usually require harsh chemicals or insecticides if only small numbers are present.

To control larger infestations, try non-toxic methods first. Remove as much of the webbing as possible using gloves, sticky tape or vacuuming. Pruning back thick vegetation and wood piles near foundations will eliminate protected nesting spots. Cracks and crevices where spider entry occurs can be caulked. Using screens on attic vents prevents them from colonizing roof spaces. Keeping basements, sheds and garages clean and dry makes them less attractive. Use yellow "bug lights" or LED lighting outdoors at night instead of traditional bulbs which attract night-flying insect meals. Sticky traps for insects can also control food sources.

For more severe infestations indoors, carefully apply desiccant dusts containing silica gel into cracks and crevices where the spiders hide. As the spiders groom themselves, they will ingest the fine particles and die off within a few days. Vacuum up any visible corpses to prevent secondary poisoning of lizards and birds that might feed on the spiders.

Are Common House Spiders Dangerous?

The common house spider gets an unfair bad reputation simply because people fear spiders in general. In truth, they are quite harmless to humans. Their bites are extremely rare and produce only mild and temporary discomfort when they do occur. They eat many pest insects, so a few spiders can benefit households looking for non-toxic ways to control flies, roaches, moths and other indoor nuisances. While unexpectedly encountering their messy webs can certainly give homeowners a fright, these docile spiders are nothing to worry about once their habits and behaviors are understood.

Other Common Virginia Spiders

Several other spider species frequently encountered by Virginians in and around their homes include the southern house spider, American house spider, barn funnel weaver, longbodied cellar spider and brown recluse spider:

Southern House Spider

The southern house spider (Kukulcania hibernalis) is medium-sized, grey to brown in color with long legs and prominent spinnerets. They build loose sheets of webbing on walls, furniture, porches and other sites, but do not catch prey this way. Instead they wander in search of insects to pounce upon. They have potent venom, but rarely bite humans.

American House Spider

The barn spider (Neoscona crucifera) is identified by an orb-style web decorated by zipper-like stabilimenta. Fast moving with banded legs, they are large, somewhat hairy spiders that come in color variations of grey, brown and orange. Common in rural structures, bites to humans are rare despite possessing medically significant venom.

Barn Funnel Weaver

The barn funnel weaver (Tegenaria domestica) constructs dense, funnel-shaped webs extending from crevices in wall voids, window or door frames, stone foundation gaps and tree holes. They are solid dark brown or grey with stripes or chevron markings when young. Fast and aggressive, they will bite if handled carelessly.

Longbodied Cellar Spider

The longbodied cellar spider (Pholcus phalangioides) build messy, chaotic webs populated by carcasses of their victims in corners of crawlspaces and ceilings. Despite their ghoulish decorating habits and off-putting appearance, they do not pose safety risks to people or pets in the home.

Brown Recluse Spider

The brown recluse spider (Loxosceles reclusa) inhabits dark, sheltered spaces in attics, crawlspaces, woodpiles and sheds. About 1cm long with a dark brown body and legs, they are identifiable by the prominent violin-shaped marking on the back. Poisonous hemolytic venom makes bites quite dangerous in rare cases. Seek medical care promptly if bitten.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.