The woodlouse spider, known scientifically as Dysdera crocata, is a common arachnid found across North America, Europe, and Asia. Its distinctive appearance often raises questions about the threat its bite poses to humans. This article addresses the nature of the woodlouse spider’s venom and what to do if bitten.
Understanding Woodlouse Spider Venom
Woodlouse spiders are venomous, not poisonous; venom is injected through a bite or sting, while poison is ingested or absorbed. Like most spiders, Dysdera crocata produces venom to subdue its prey, primarily woodlice, with venom specifically adapted to affect these hard-shelled crustaceans. The woodlouse spider possesses notably large, forward-pointing fangs, or chelicerae, designed to pierce woodlice exoskeletons. While these fangs can penetrate human skin, the venom itself is generally not considered harmful to humans. Bites cause minor pain, primarily due to the mechanical puncture by the large fangs rather than venom potency, and this pain typically lasts for less than an hour.
Typical symptoms of a woodlouse spider bite include localized pain, redness, swelling, and itching at the bite site. These reactions are usually mild and comparable to a bee or wasp sting. Severe reactions are rare, and the venom is not potent enough to cause significant harm to humans or even pets.
Identifying a Woodlouse Spider
Identifying a woodlouse spider involves observing several distinct physical characteristics. They typically have a reddish-brown cephalothorax and legs, contrasting with a grayish-white or creamy abdomen. Their body length ranges from about 0.25 inches for males to 0.5 inches for females.
One of their most recognizable features is their prominent, large fangs that project forward. Unlike most spiders, woodlouse spiders possess six eyes, usually arranged in two rows of three or a semicircle. They do not build webs for catching prey; instead, they are active nocturnal hunters, relying on their speed and powerful fangs.
Woodlouse spiders are commonly found in damp environments where their prey is abundant. These habitats include areas under rocks, logs, leaf litter, and compost piles outdoors. Indoors, they may be encountered in basements, garages, or other moist areas, particularly during cooler months when they seek shelter.
What to Do After a Bite
If bitten by a woodlouse spider, clean the bite area thoroughly with mild soap and water to prevent infection. Apply a cold compress or ice pack to reduce pain and swelling, for about 15 minutes each hour.
Over-the-counter pain relievers (e.g., ibuprofen) can manage discomfort, and antihistamines may alleviate itching. Most woodlouse spider bites resolve quickly without complications. Monitor the bite for any signs of worsening symptoms or infection, such such as increasing redness, warmth, pus, or spreading pain.
Seek medical attention for signs of an allergic reaction, such as difficulty breathing, facial swelling, severe pain, or abdominal cramping. Medical consultation is also advisable if symptoms persist or worsen, or if you are unsure about the spider type. Even though woodlouse spider bites are generally minor, professional medical advice is recommended for any concerning symptoms.