Underside of woodlouse, coloured scanning electron micrograph (SEM). Woodlice are terrestrial crustaceans from the order Isopoda. They have a flattened segmented body which allows some families of woodlice to roll up completely into a spherical shape as a defence mechanism. They have seven pairs of jointed legs. Woodlice are often found living in damp and dark conditions feeding on dead wood and plants. Magnification: x30 when printed at 10cm wide.