Warm summer weather is likely to drive woodlice into your home, seeking out an holes or gaps to escape the heat. And although they are not the nicest looking critters, they are however essential to the ecosystem in the way they recycle nutrients and often are a food source for prettier creatures.
Woodlice are both arthropods (as their bodies are divided into segments and their legs have several joints) and terrestrial isopods (a class Crustacea, a sub-order Isopoda) and have more in common with the likes of shrimp than other insects. They have a rigid, yet long segmented exoskeleton and usually feed on dead plant material and are often only active at night.
However, they are actually a great help to us because of what they eat. They may eat the odd seedling, but they are not destructive to gardens and plants and will mostly eat decaying or dead plant matter and animal dung (great if you have pets). Most of which is why you will see big groups of woodlice under garden rocks or in compost heaps.
Their diet of dead and decaying matter helps to recycle nutrients in their habitat and in turn the soil. They are also eaten by many other species including, but not limited to toads, shrew, ground beetles, harvestmen and some spiders.
So they may come into your home when the weather is hot, they are a good indicator of a happy healthy garden that is bound to be visited by plenty of wildlife.