The woodlouse spider, scientifically known as Dysdera crocata, is an arachnid often encountered in homes and gardens. Its name directly reflects its primary prey, woodlice. This spider is generally reclusive.
Appearance and Identification
Its cephalothorax, which is the fused head and thorax, and its legs are typically a reddish-orange or dark red color. This contrasts with its abdomen, which is elongated, shiny, and ranges from grayish-white to pinkish-tan.
A prominent feature of the woodlouse spider is its large, forward-pointing chelicerae, or fangs, which are disproportionately large for its body size. These fangs are adapted for piercing the tough exoskeletons of its prey. Unlike most spiders that have eight eyes, Dysdera crocata has six eyes, arranged in a tight oval or semicircle on its head. Adult females are typically larger than males, measuring about 11–15 mm in body length, while males are slightly smaller, around 9–10 mm.
Habitat and Behavior
Woodlouse spiders prefer damp, secluded environments, often found under rocks, logs, leaf litter, and in gardens. Indoors, they commonly inhabit basements, crawl spaces, and other areas with high humidity. These spiders do not spin webs to catch prey; instead, they are nocturnal, active hunters.
Their hunting strategy involves actively searching for prey at night, using their powerful fangs to pierce the tough outer shells of woodlice. While woodlice are their primary diet, they also prey on other invertebrates such as silverfish, earwigs, millipedes, and beetles. Despite their predatory nature, woodlouse spiders are generally reclusive and non-aggressive towards humans, typically only biting if provoked or accidentally trapped.
Bite and Interaction with Humans
Bites from a woodlouse spider are rare and usually occur when the spider feels threatened or is accidentally pressed against the skin. The bite typically causes localized pain, redness, and itching, often described as similar to a bee sting. The discomfort from the bite usually subsides within an hour.
The venom of Dysdera crocata is not considered medically significant to humans. While the bite can be painful due to the mechanical puncture from its large fangs, it poses little risk. It is advisable to seek medical attention if symptoms worsen, signs of infection appear, or if an individual experiences a known severe allergic reaction to insect bites. To avoid bites, simple precautions include wearing gloves when gardening and shaking out clothing or shoes before use, especially in areas where these spiders might reside.