The woodlouse spider, Dysdera crocata, is a species of spider that preys primarily upon woodlice. Other common names refer to variations on the common name of its prey, including woodlouse hunter, sowbug hunter, sowbug killer, pillbug hunter and slater spider.
Woodlouse spiders are usually found under logs, rocks, bricks, and in leaf litter in warm places, often close to woodlice. They have also been found in houses. They spend the day in a silken retreat made to enclose crevices in, generally, partially decayed wood, but sometimes construct tent-like structures in indents of various large rocks. Woodlouse spiders hunt at night and do not spin webs.
Because of its relatively large fangs and wide gape, the woodlouse spider is an unusually dominant predator for its size. Like many other Dysdera spiders, it frequently dominates, and sometimes kills, other spiders and centipedes.
The courtship of these spiders is typically aggressive and mates risk injury from each other’s large chelicerae. The female lays her eggs in a silken sac and is believed to look after her young after hatching.
They have been known to bite humans if handled. Verified bites have caused no major medical problems. Localized itchiness at the bite site has been reported in some cases.