Cellar spiders, recognized by their long, thin legs, are common in many households. They often inhabit undisturbed areas, leading to questions about their potential threat, particularly concerning bites. This article clarifies common misconceptions and provides accurate information about cellar spiders and what happens if one bites you.
Identifying Cellar Spiders
Cellar spiders, belonging to the family Pholcidae, have small, oval-shaped bodies, ranging from pale yellowish to light brown or gray. Their most distinguishing feature is their eight very elongated and slender legs, which can make them appear fragile. Adult female long-bodied cellar spiders can have bodies up to 8 mm long with front legs extending up to 50 mm.
These spiders prefer dark, damp, quiet environments like cellars, basements, crawl spaces, and garages, earning them their common name. They construct loose, irregular, and often messy webs, typically found in corners, near ceilings, or over windows. Unlike some other spider species, cellar spiders do not typically consume old webs; instead, they layer new silk, leading to a noticeable accumulation of cobwebs.
The Nature of a Cellar Spider Bite
Concerns about cellar spider bites often stem from an urban myth claiming their venom is highly potent but fangs are too short to penetrate human skin. This widely circulated myth is not supported by scientific evidence. Cellar spiders do possess fangs, approximately 0.25 mm long, a length capable of penetrating human epidermis (less than 0.1 mm thick). Despite this, reports of cellar spider bites are rare.
Cellar spiders are generally non-aggressive and rarely bite humans, even when provoked. If a bite occurs, the sensation is typically a mild, fleeting prick, if noticed at all. Research indicates their venom is quite mild and not considered medically significant to humans. Studies have shown the venom of Pholcus phalangioides to be significantly weaker than that of medically concerning spiders like the brown recluse. Their primary method of immobilizing prey, even larger spiders, often involves wrapping them in silk rather than relying solely on venom.
What to Do After a Cellar Spider Bite
Given the rare and mild nature of cellar spider bites, serious reactions are not expected. If bitten, recommended first aid is straightforward: Clean the bite area gently with mild soap and water to prevent infection. Applying a cool compress or ice pack for about 15 minutes each hour can help reduce minor pain or swelling.
Any discomfort, such as mild itching or slight redness, is usually minimal and resolves quickly, comparable to a mosquito bite. Over-the-counter pain relievers or antihistamines can be used for minor symptoms. Medical attention is almost never required for a cellar spider bite. However, seek professional medical advice if you experience unusual or worsening symptoms, such as spreading redness, increased pain, significant swelling, or signs of infection, as these might indicate a different issue or a bite from another type of spider.