Woodlouse Spider

Dysdera crocata

Summary 4

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. These are woodlouse hunter, sowbug hunter, sowbug killer, pillbug hunter and slater spider.

Appearance 5

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 though this species is not often found near human habitation.

Behavior 5

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.

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. 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.

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.

Distribution 5

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

Sources and Credits

  1. (c) Kurt Andreas, some rights reserved (CC BY-NC-SA), http://www.flickr.com/photos/42227089@N00/5812923363/
  2. (c) B Staffan Lindgren, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/bslindgren/25912831683/
  3. (c) J. Maughn, some rights reserved (CC BY-NC), https://www.flickr.com/photos/jmaughn/12386979793/
  4. Adapted by kmarie333 from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Dysdera_crocata
  5. (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Woodlouse_spider

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