Although woodlice have been mentioned in BugBlog a few times, they haven't been the main character in any post yet, and this has to be addressed. This little group I found yesterday under a pot gives me the perfect excuse. There are over 3,000 described species of terrestrial isopods (woodlice) in the world, with only 35 native to the UK. The Common Rough Woodlouse (Porcellio scaber) - above- is one of the most common. Unlike the Pill Woodlouse (Armadilium), it is unable to roll into a ball, and instead, its defence mechanism consists in grasping the substrate and pressing its dorsal armour against it, so that its more vulnerable underside is protected. Its nocturnal habits and love of humid places reflect the fact that it loses water very easily from its body due to transpiration as their surfaces are not waterproof. Woodlice absorb water from their surroundings when they rest under stones, in compost heaps or similar places and they lose it when they forage away from their refuge. They are detritivores and feed on dead vegetable matter and therefore are involved in the decomposition of dead leaves and the production of compost.
Woodlice usually have separate sexes, that is, there are males and females. Females brood the eggs and their young in their first instar, suplying them with nutrients and water, in a pouch under their body. In the common rough woodlouse, females can produce three broods (of around 20 young) a year in good conditions. Breeding is very seasonal, and starts when days become longer (16 h light). Woodlice can live several years.