Barn spiders (Araneus cavaticus) are common orb-weaving spiders often found near human structures like barns, sheds, and porches. This article clarifies information about barn spider venom, identification, and bite management.
Understanding Barn Spider Venom
Barn spiders, like most spiders, do possess venom, but it is generally not considered medically significant to humans. Their venom is primarily adapted for subduing insect prey, such as flies and mosquitoes, which become entangled in their webs. A bite from a barn spider is rare, typically only occurring if the spider feels directly threatened or is accidentally squeezed.
If a bite does occur, the symptoms are usually mild and localized, often comparable to a bee sting. These might include minor pain, redness, and slight swelling or itching at the bite site. Unlike the venom of medically significant spiders such as black widows or brown recluse spiders, barn spider venom is not potent enough to cause serious systemic reactions in people.
Identifying Barn Spiders
Barn spiders are identified by their physical traits and web-building habits. They are typically yellow, brown, or reddish-brown, with striped legs. Females are larger than males, reaching 20-25 mm (three-quarters of an inch to an inch) in length, with a large, round abdomen. The underside of their abdomen is often black with white markings.
Barn spiders construct large, circular, orb-shaped webs, often with symmetrical spokes. They build these webs in sheltered locations like doorways, window frames, eaves, barns, and sheds. Nocturnal, they are most active at night, often building a new web daily and resting in a nearby hiding spot during the day.
What to Do if Bitten
Barn spider bites are uncommon and usually cause only minor reactions. If bitten, clean the affected area with mild soap and water. Apply a cold compress or ice pack to reduce pain and swelling. Over-the-counter pain relievers can manage discomfort, and antihistamines may alleviate itching.
Seek medical attention if symptoms worsen, or if signs of infection develop such as increasing redness, warmth, or pus. Medical consultation is also advised if you experience an allergic reaction, such as facial swelling or difficulty breathing, or if you are unsure of the spider type and symptoms are concerning, like severe pain or spreading skin inflammation.