Cobweb spiders are common in homes and gardens, often causing concern. Many wonder if these small arachnids, known for their irregular webs, pose a biting threat. Understanding their behavior and characteristics can clarify their interactions with humans.
The Truth About Cobweb Spider Bites
Cobweb spiders (family Theridiidae) can bite, but are not aggressive towards humans. Bites usually happen when a spider feels threatened or is accidentally pressed against skin, like when putting on clothes. Most cobweb spiders found in homes are harmless; their venom primarily affects insects. The black widow spider (Latrodectus mactans) is a notable exception within this family, known for its neurotoxic venom. However, black widows do not represent the biting capabilities of most other cobweb spiders.
Understanding Cobweb Spider Bites
A bite from a common cobweb spider results in mild, localized reactions. These may include a small red bump, slight itching, or minor swelling at the bite site. Symptoms resolve quickly, within a day or two, with basic at-home care. Unlike bites from more medically significant spiders, systemic symptoms are rare. Many skin irritations are mistakenly attributed to spider bites, making identification difficult without witnessing the bite.
Identifying Common Cobweb Spiders
Common cobweb spiders are characterized by their irregular, tangled, and messy-looking webs. These webs lack a distinct geometric pattern, unlike more organized spider webs.
Cobweb spiders are small to medium, measuring 3 mm to 10 mm in body length. They have a rounded abdomen and long, thin legs, with the first pair often the longest. These spiders inhabit undisturbed areas like corners of rooms, basements, garages, sheds, and under decks. They hang upside down in their webs, waiting for prey.
What to Do After a Bite
If a cobweb spider bite occurs, clean the affected area with mild soap and water. Apply a cold compress, such as a damp cloth or ice pack, to reduce pain and swelling. Elevating the bitten limb can also help minimize swelling. Seek medical attention if symptoms worsen, spread, or show signs of infection, such as increasing redness, warmth, pus, or fever. You should seek professional medical advice if the bite is from a known dangerous spider, like a black widow, or if you are unsure of the spider’s identity and experience severe pain or systemic reactions.