Woodlouse Spider: Identification and Extermination

The woodlouse spider, scientifically known as Dysdera crocata, is an intriguing and specialized arachnid species renowned for its unique hunting habits and association with woodlice and other small arthropods. This comprehensive guide offers a wealth of information, encompassing everything from identifying woodlouse spiders to delving into their captivating behavior. Additionally, it provides valuable insights into effective techniques for managing woodlouse spiders, should the need arise. By understanding the ecological role of woodlouse spiders in controlling woodlice populations and their generally harmless nature, we can appreciate their place within the intricate web of interactions in the natural world.



Woodlouse spiders possess distinct characteristics that aid in their identification:
Size: Adult woodlouse spiders range from 8 to 15 mm in body length, with females typically larger than males.
Appearance: They have a reddish-brown to dark brown cephalothorax and abdomen. Their bodies are flattened, with long legs that allow them to maneuver easily in narrow crevices.
Chelicerae: One distinguishing feature of woodlouse spiders is their large, powerful chelicerae, which they use to crush and subdue their prey.
Specialized Diet: Woodlouse spiders have a unique and specialized diet. Unlike many other spiders that primarily feed on insects, woodlouse spiders predominantly prey on woodlice (also known as pill bugs or sow bugs). They have adapted to their diet by possessing specialized mouthparts and venom that allows them to efficiently capture and subdue their woodlouse prey.




Woodlouse spiders, scientifically known as Dysdera crocata, are fascinating arachnids that exhibit interesting behaviors and adaptations. These predominantly nocturnal spiders can often be found in a variety of moist habitats, including gardens, leaf litter, and damp basements. Their preference for such environments is closely tied to their primary prey source – woodlice. Woodlouse spiders have evolved to specialize in hunting woodlice, but they may also prey on other small arthropods that share their habitat. Woodlouse spiders have a relatively restricted distribution, primarily found in certain regions of Europe, including the Mediterranean region and parts of the United Kingdom. They have been introduced to other areas, such as North America, but their populations tend to be localized. These spiders are adept at navigating their surroundings in low-light conditions, and their activity peaks during the nighttime when their preferred prey, woodlice, are most active. Woodlouse spiders employ their stealth and agility to capture and subdue their prey. They possess specialized mouthparts and venom that aids in immobilizing their victims.
When threatened, woodlouse spiders exhibit a defensive behavior known as “curling.” They curl their bodies and raise their legs in a defensive posture, displaying their reddish fangs as a warning. However, woodlouse spiders are generally non-aggressive towards humans and are unlikely to bite unless handled or provoked.

Extermination Techniques

If the presence of woodlouse spiders becomes a concern, the following extermination techniques can be employed:

Non-Chemical Methods:

  • Physical Removal: Use a soft brush or vacuum cleaner to capture woodlouse spiders and remove them from infested areas. Carefully release them outdoors or dispose of them properly.
  • Habitat Modification: Reduce moisture levels and eliminate woodlice populations by addressing any damp conditions, repairing water leaks, and removing decaying organic matter.

Chemical Control:

  • Targeted Insecticides: In severe infestations or specific situations, professional pest control services may apply targeted insecticides labeled for spider control. Consult with a licensed pest control expert for appropriate recommendations.

Despite their formidable hunting abilities, woodlouse spiders are not known to pose any significant threat to humans. They are generally non-aggressive and prefer to avoid confrontations. In the rare event that a human comes into contact with a woodlouse spider, it is unlikely to result in harm. These spiders are more likely to retreat or seek shelter rather than display aggression towards humans.


For professional assistance or more information, please contact our pest control experts who are experienced in spider management.