The ecological niche of the woodlice Porcellio scaber.
The woodlouse Porcellio scaber is native to Europe but also commonly found in New Zealand. They live in cool, dark, damp microhabitats such as in rotting wood, under rocks, in caves and leaf litter. Small insectivorous rodents and birds as well as some spiders feed on woodlice. In the rotting log from which I gathered my specimens there were also millipedes, crickets, weta and spiders living.
Woodlice have physical adaptations to allow them to live in a variety of habitats, provided they are dark and damp. These include; * A mottled grey-brown colour for camouflage. * Olfaction structures on the ends of the large antennae or covering the surface of the antennulae (smaller set of antennae). These are used to find food and other woodlice. * The excretion of nitrogenous waste as ammonia gas through their exoskeletons. This means that as well as being permeable to ammonia their exoskeletons are also permeable to water. (This means in arid conditions the woodlouse dries out and in humid conditions it absorbs a lot of water) * Up to seven sets of legs. * Pores opening to simple lungs. The pore is unable to be closed resulting in constant water loss from the lungs.
Behavioural adaptations such as: * Freezing when exposed or attacked. (I also observed when I picked the woodlice up for the experiment that if they were accidentally rolled over on their backs, they would curl their legs up and play dead) this combined with their good camouflage makes it hard for predators to see them. * Burrowing back underground when exposed to light. * Clustering together (a thigmokenetic response) to reduce the surface area to volume of the whole group resulting in a reduction of water loss.
Woodlice are very vulnerable to desiccation. As one of the few terrestrial animals in the phylum crustacea they lack some of the structures other land dwelling arthropods