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Common Rough Woodlouse

Porcellio scaber
Porcellio scaber
Did you know that… ?
  • …woodlice cannot roll themselves into a ball, unlike pillbugs (Armadillium), which can do so?
  • …when woodlice molt, they first discard the rear part of their exoskeleton, then two to three days later, discard the front part?
  • …woodlice do not excrete urine, but instead give off ammonia gas through their exoskeleton, which is why places where the live in large numbers smell bad?
  • …the original home of this species was Europe, from where it spread throughout the world?
  • …woodlice have seven pairs of legs, but the last pair is missing in freshly hatched young?
Porcellio scaber - image is under CC BY-NC
General info
Phylum: Arthropoda
Class: Malacostraca
Order: Isopoda
Size: 1.5 cm
Food: dead plant material
Habitat: basements, damp walls
Distribution: world wide
Relationship with humans: pest

Woodlice are one of the few crustaceans that live permanently on dry land. For respiration, they use a system of thin tubes in their abdomen. They prefer moist environments, like basements and building walls. During the day, they normally hide under rocks, wood or fallen leaves. They live on dead plant material. Unless they multiply to very large numbers, they are practically harmless. After mating, females carry about twenty fertilized eggs on the underside of their bodies, until the young hatch. Woodlice can live up to two and a half years. These crustaceans come from Europe, but riding with people has enabled them to spread all over the world.