''Armadillidium vulgare'', the common pill-bug, potato bug, common pill woodlouse, roly-poly, slater, doodle bug, or carpenter, is a widespread

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

woodlouse A woodlouse (plural woodlice) is an isopod crustacean from the polyphyleticThe current consensus is that Oniscidea is actually triphyletic suborder Oniscidea within the order Isopoda. They get their name from often being found in old wood ...

. It is the most extensively investigated terrestrial isopod species.

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 millipede Pill millipedes are any members of two living (and one extinct) orders of millipedes, often grouped together into a single superorder, Oniscomorpha. The name Oniscomorpha refers to the millipedes' resemblance to certain woodlice (Oniscidea), also ...

s such as ''

Glomeris marginata ''Glomeris marginata'' is a common European species of pill millipede. It is a short millipede, rounded in cross-section, which is capable of rolling itself up into a ball (" volvation") when disturbed. This behaviour is also found in the pill wo ...

''. It can be distinguished from ''

Armadillidium nasatum ''Armadillidium nasatum'' is a large, Western European-based species of woodlouse that has been introduced to North America, along with ''Armadillidium vulgare'' also found in other parts of Europe. Description ''Armadillidium nasatum'' can ...

'' 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 Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an ad ...

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 The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

, ''A. vulgare'' is very common in southern and

eastern England The East of England is one of the nine official regions of England. This region was created in 1994 and was adopted for statistics purposes from 1999. It includes the ceremonial counties of Bedfordshire, Cambridgeshire, Essex, Hertfordshire ...

, but is more confined to coastal areas in the north. Similarly, in

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

, ''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 Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical term.Matt RosenberPopu ...

of up to . It is now one of the most abundant invertebrate species in

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

coastal

grassland A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...

habitats. It has also been introduced, to a lesser extent, to sites across the world.

Relationships with humans

Because of their unusual yet non-threatening appearance, some ''Armadillidium vulgare'' are kept as

pet A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive appearances, intelligence ...

s in areas throughout the world. 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 PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...

Mitochondrial genome

Most metazoans have circular mitochondrial genomes, but ''A.vulgare'' has an unusual combination of both circular and linear mitochondrial DNA.

Gallery

File:Armadillidium vulgare 000.jpg, ''Armadillidium vulgare'' beginning to unroll from its defensive posture File:Cloporte01.JPG, A related isopod (sowbug) with its clutch on its belly File:A. Vulgare adults.jpg, Solid grey ''A. vulgare'' as adults

References

External links

* * {{Authority control Woodlice Woodlice of Europe Crustaceans described in 1804