Many people encounter spiders in their homes and often wonder about their potential danger, especially regarding “dust spiders.” This article addresses common misconceptions and provides information about the safety of these common indoor arachnids.
Common House Spiders Known as “Dust Spiders”
The term “dust spider” is not a scientific classification but a general description for various spider species found indoors. Common examples include the common house spider (Parasteatoda tepidariorum), typically tan to nearly black and about 5-6 millimeters long. The long-bodied cellar spider (Pholcus phalangioides) is identifiable by its very long, thin legs and small, gray body. The domestic house spider (Tegenaria domestica), also known as the barn funnel weaver, is typically brown or gray and measures between 7 and 18 millimeters.
These spiders build webs in undisturbed areas like corners, basements, or attics, where dust accumulates, giving them their “dust spider” name. Their webs are irregular or funnel-shaped, trapping insects. They are generally small to medium-sized web-building spiders.
Are They Venomous?
Spiders are venomous, not poisonous. This means spiders inject toxins through a bite, while poisonous organisms are harmful if ingested or touched. Common house spiders, including “dust spiders,” use venom primarily to immobilize insect prey like flies, mosquitoes, and ants.
The venom of these spiders is mild and not medically significant to humans. For example, Pholcus phalangioides venom has a weak effect even on insects, and its effects on humans are negligible. Parasteatoda tepidariorum venom is also not dangerous to humans, despite belonging to the same family as black widow spiders. While their venom contains neurotoxins, these are not potent enough to cause severe reactions in people.
Understanding Their Bite
Bites from common house spiders are rare, occurring only when the spider feels threatened or is accidentally pressed against the skin. These spiders are not aggressive and avoid human contact. If a bite occurs, the reaction is mild, often compared to a mosquito bite or bee sting.
Symptoms may include a small red bump, localized itching, or minor swelling. Severe reactions are uncommon and generally due to an allergic response, not venom potency. Clean the bite with soap and water; apply a cold compress for discomfort. If symptoms worsen, spread, or an allergic reaction (e.g., difficulty breathing, widespread rash) is suspected, seek medical attention.
Coexisting with House Spiders
House spiders are non-aggressive, reclusive creatures that play a beneficial role indoors. They act as natural pest control, preying on household insects like flies, mosquitoes, and cockroaches. This helps manage pest populations without chemical pesticides.
To minimize encounters, regular dusting, vacuuming, and sealing cracks in foundations and around windows are effective. Understanding their behavior and limited threat alleviates apprehension, as they are a natural part of most indoor ecosystems. Their presence often indicates a healthy indoor environment with a food source.