Nature Table: Woodlice

Many people call them ‘slaters’, which is probably a better name because a woodlouse is not particularly associated with wood and is certainly not a louse. They are, however, slate-coloured. Woodlice are not insects, they are crustaceans and related to shrimps.

Many people dislike them, which is a bit unfair because they are not only generally harmless they also perform a vital ecological function. They are what biologists call a detritivore, which means an animal that eats rubbish. Just as binmen perform a vital role that is often not appreciated, the woodlouse gets little thanks for its tireless work in cleaning up dead plant material.

Occasionally however, when dead plant material is in short supply, woodlice will create their own by killing living plants, usually young seedlings, which can make them a garden and greenhouse pest. They are largely nocturnal, spending the day hiding in dark, damp places. There are 32 species in Ireland including the common rough woodlouse and the pill bug, which curls up like a hedgehog when it’s disturbed.