Big Brown Spiders in Virginia: Appearance, Bites, and Control

Big Brown Spiders in Virginia

Virginia is home to a variety of spider species, some of which can reach fairly large sizes. One of the most notable is the big brown spider, which can be found throughout the state. While not considered highly dangerous, the big brown spider does have a mildly toxic venom that can cause mild symptoms in humans if bitten.

Appearance and Identification

The big brown spider (Eratigena atrica) is one of the most common house spiders in Virginia and throughout North America. As their name suggests, these spiders are identified by their large, brown bodies which can reach up to 25mm (1 inch) in length. Their legs span approximately 2-3 inches tip to tip.

Big brown spiders have a hairy appearance, with banded legs. Their cephalothorax (head region) is typically a lighter brown or tan compared to the rest of the body. The abdomen has a marbled or mottled pattern of lighter brown, gray, and black. Females tend to be slightly larger than males.

One key identifier is the eyes - big brown spiders have three rows of four small eyes each. Their legs point upward when at rest. Big brown spiders build messy-looking cobwebs in corners or crevices of structures.

Habitat and Behavior

In Virginia, big brown spiders can be found in a wide variety of habitats, especially in and around human structures. They like dark, sheltered areas such as attics, garages, sheds, and basements. They may also live under rocks, logs, and debris outdoors.

Big brown spiders are nocturnal predators that wait in their webs at night to ambush prey like insects, other spiders, and small vertebrates. They do not actively hunt. During the day, they retreat to a corner within their web. These spiders may wander indoors in search of food and shelter during the colder months.

Big brown spiders produce sticky, irregular webs that lack definite shape or organization. The webs frequently include dead prey, insect parts, and other debris. Females continuously produce egg sacs, each containing up to 35 eggs, from spring through fall. Spiderlings emerge in 5-6 weeks and reach maturity in about a year.

Bites and Venom

All spiders have venom to subdue prey, but most species pose little risk to humans. The big brown spider does have more potent venom than other common house spiders. However, bites are uncommon and symptoms are generally mild.

When bites do occur, they usually happen when a spider gets accidentally trapped or squeezed against bare skin. Common bite symptoms include:

• A mild stinging or burning sensation
• Redness and swelling at the bite site
• Mild itching or pain
• Small blisters or lesions

In rare cases, the reaction may be more severe with symptoms such as nausea, sweating, headache, abdominal pain, and localized swelling. Serious complications are very uncommon though.

Bites can be safely treated at home in most situations. Clean the bite area with soap and water and apply an antiseptic cream. Over-the-counter pain medication can help relieve discomfort. Seek medical care if severe swelling, blistering, or other worrisome symptoms develop.

Prevention and Control

Big brown spiders pose minimal risks to people and pets, so control is not essential in most cases. But bites can be avoided by taking some simple precautions:

• Clear clutter such as piles of debris, wood, or rock landscaping where spiders may live.
• Store boxes off the floor and regularly vacuum attics, basements, and garages.
• Seal cracks around windows, doors, and foundations to block entry.
• Avoid reaching into dark, hidden spaces where spiders may reside.
• Inspect or shake out shoes, towels, and clothing before use.
• Carefully handle dead wood piles or debris.

If control is desired, spraying insecticides labeled for spider treatment into garages, attics, basements or other infested areas can help reduce populations. Be sure to follow all label directions carefully. Insecticides with active ingredients like lambda-cyhalothrin, bifenthrin, or deltamethrin are effective against spiders when applied properly. Residual sprays or dusts tend to work better than fogs or mists.

The use of sticky traps or vacuum suction around baseboards and window frames can also help remove wandering spiders. Natural repellents like essential oils may provide limited relief as well.

Are They Dangerous?

The big brown spider rarely causes serious harm to people. While their venom can potentially produce skin lesions or other uncomfortable reactions in some individuals, medically significant complications are uncommon following bites.

Big brown spiders are timid and non-aggressive. They only bite when accidentally disturbed or trapped against skin. These spiders spend most of their time hidden in undisturbed webs and are not prone to attacking or chasing people.

Parents should teach children not to touch spiders and to request adult assistance for removal. This helps avoid accidental bites. There is no need to panic or actively eliminate populations of big brown spiders on a routine basis though.

For people with severe allergies or medical conditions, seek evaluation after any spider bite, even if symptoms seem minor at first. Otherwise, take basic first aid measures at home for uncomplicated bites. Keep the bite location clean, use cold compresses, take pain relievers, and monitor for spreading redness, swelling or other concerning reactions.

Key Takeaways

• The big brown spider is one of the most common house spiders found throughout Virginia homes, garages and sheds.
• They have large, brown, hairy bodies about an inch long with banded legs spanning 2-3 inches.
• Big brown spiders build messy cobwebs in secluded, sheltered areas and wait to ambush insect prey.
• They have mildly venomous bites but are unlikely to cause major illness. Bite symptoms include mild pain, itching, redness and swelling.
• Control is typically not needed but sealing cracks, clearing clutter, and vacuuming regularly can help reduce populations.
• Teach children not to touch spiders and to get adult help for removal. Seek medical care for any severe reactions to bites.

While not rare in Virginia, the big brown spider is not an aggressive species and rarely causes significant issues or dangers in homes. Basic pest control and bite prevention measures can help limit unwanted encounters with these spiders.

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.