Armadillidium vulgare, the common pill-bug, potato bug, common pill woodlouse, roly-poly, slater, doodle bug, or carpenter, is a widespread European species of woodlouse. It is the most extensively investigated terrestrial isopod species.
Armadillidium vulgare may reach a length of 18 millimetres (0.71 in), 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. vulgaredoes not leave such a gap.
Because of their unusual yet non-threatening appearance, some Armadillidium vulgare are kept as pets in areas throughout the U.S., typically among children. Different lineages are bred, usually in regards to color, in order to provide stock to hobbyists. One supposed variation, “Punta Cana,” is often referred to as Armadillidium sordidum, while others insist it is a variety of A. vulgare. Keeping a pet pill bug requires a very moist habitat with limited light and abundant decaying botanical matter. They can often live up to three years. Among non-hobbyist adults, they are often seen as unwanted (but essentially harmless) home pests.