Woodlouse Spider

Dysdera crocata is instantly recognisable: 9–15 mm, with a shiny dark orange-red cephalothorax and legs contrasting with a smooth, glossy cream-grey abdomen, six eyes rather than eight, and disproportionately huge forward-projecting fangs adapted for piercing the armoured shells of woodlice. Females deposit 30–70 eggs in a loose silk cell in soil or under stone and guard the brood; the spiders live one to two years and can breed year-round in mild, damp conditions.

This is a nocturnal, webless hunting spider that spends the day sealed in a silken cell under stone, bark or debris and emerges at night to hunt pillbugs and sowbugs almost exclusively. The oversized chelicerae look alarming and the species can deliver a defensive bite if trapped against skin, but venom effects are minor and local — brief sharp pain and itching, with no medically significant sequelae despite the spider's reputation. Its presence is a direct indicator of a large woodlouse population, so prey management is the core control lever.