Woodlouse spider

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Woodlouse spider
Dysdera crocata.jpg
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Suborder: Araneomorphae
Family: Dysderidae
Genus: Dysdera
Species: D. crocata
Binomial name
Dysdera crocata
C. L. Koch, 1838
  • D. interrita
  • D. gracilis
  • D. rubicunda
  • D. wollastoni
  • D. maurusia
  • D. balearica
  • D. coerulescens
  • D. crocota
  • D. australiensis
  • D. sternalis
  • D. cretica
  • D. menozzii
  • D. palmensis
  • D. inaequuscapillata

The woodlouse spider, Dysdera crocata, is a species of spider that preys exclusively 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.


Female specimens are 15–30 mm long, while males are 10–15 mm. They have six eyes, a dark-red cephalothorax and legs, and a shiny (sometimes very shiny) yellow-brown abdomen. Notably, they have disproportionately large chelicerae. Dysdera crocata is difficult to distinguish from the much less common Dysdera erythrina[1] though this species is not often found near human habitation.


D. crocata, which originated in the Mediterranean area, now has a cosmopolitan distribution (see map).[2]


Woodlouse spiders are usually to be found under logs in warm places, often close to woodlice. They have 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 without the use of a web.

Male Dysdera crocata

Their diet consists exclusively of woodlice which—despite their tough exoskeleton—are pierced easily by the spider's large chelicerae; the spider is able to inject venom into the woodlouse's soft underbelly while avoiding any noxious defensive chemicals.[2] Laboratory experiments have shown D. crocata will take other invertebrates, and shows no particular preference for slaters; these are simply the dominant prey in its habitat.[2]

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 like the "Mothercare" spider (Theridion sisyphium).

They have been known to bite humans if handled. Their bite is less painful than a bee sting and the venom causes no major medical problems. Localized itchiness at the bite site has been reported in some cases.[3]


  1. ^ Cooke, J. A. L. (June 1965), "Systematic aspects of the external morphology of Dysdera crocata and Dysdera erythrina (Araneae, Dysderidae)", Acta Zoologica 46 (1-2): 41–65, doi:10.1111/j.1463-6395.1965.tb00726.x 
  2. ^ a b c Vink, Cor J. (2015). A Photographic Guide to Spiders of New Zealand. Auckland: New Holland. p. 29. ISBN 978-1-86966-403-9. 
  3. ^ Vetter, R. S.; Isbister, G. K. (2006). "Verified bites by the woodlouse spider, Dysdera crocata". Toxicon 47 (7): 826–829. doi:10.1016/j.toxicon.2006.02.002. PMID 16574180. 

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