Armadillidium vulgare
Armadillidium vulgare, the common pill-bug, common pill woodlouse, roly-poly, potato bug, slater, doodle bug, or carpenter, is a widespread European species of woodlouse. It is the most extensively investigated terrestrial isopod species. It is native to Mediterranean Europe, but as an introduced species they have become naturalized in almost all suitable ecosystems. They are kept as pets by hobbyists for their wide range of possible color variations.
Description
Armadillidium vulgare may reach a length of, and is capable of rolling into a ball when disturbed; this ability, along with its general appearance, gives it the name pill-bug and also creates the potential for confusion with pill millipedes such as Glomeris marginata. It can be distinguished from Armadillidium nasatum and Armadillidium depressum by the gap that A. nasatum and A. depressum leave when rolling into a ball; A. vulgare does not leave such a gap.Ecology
Armadillidium vulgare is able to withstand drier conditions than many other woodlouse species, and is restricted to calcareous soils or coastal areas. It feeds chiefly on decaying plant matter, but also grazes lichens and algae from tree bark and walls.It is able to regulate its temperature through its behaviour, preferring bright sunshine when temperatures are low, but remaining in shadow when temperatures are high; temperatures below or above are lethal to it. A. vulgare is less susceptible to cold during the night, and may enter a state of dormancy during the winter in order to survive temperatures that would otherwise be lethal.
Distribution
The native distribution of A. vulgare ranges across Europe, especially in the Mediterranean Basin. In the United Kingdom, A. vulgare is very common in southern and eastern England, but is more confined to coastal areas in the north. Similarly, in Ireland, A. vulgare is common in the south and east, but rarer in the north and west.A. vulgare has also been introduced to many locations in North America, where it may reach population densities of up to. It is now one of the most abundant invertebrate species in California coastal grassland habitats. It has also been introduced, to a lesser extent, to sites across the world.