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

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

woodlouse Woodlice are terrestrial isopods in the suborder Oniscidea. Their name is derived from being often found in old wood, and from louse, a parasitic insect, although woodlice are neither parasitic nor insects. Woodlice evolved from marine isopods ...

. It is the most extensively investigated terrestrial

isopod Isopoda is an Order (biology), order of crustaceans. Members of this group are called isopods and include both Aquatic animal, aquatic species and Terrestrial animal, terrestrial species such as woodlice. All have rigid, segmented exoskeletons ...

species. It is native to Mediterranean Europe, but as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

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 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 woo ...

''. It can be distinguished from '' Armadillidium nasatum'' and ''

Armadillidium depressum ''Armadillidium'' () is a genus of the small terrestrial crustacean known as the woodlouse. It is one of 18 genera nested within the family Armadillidiidae. ''Armadillidium'' is also one of the groups commonly known as pill woodlice, leg pebble ...

'' 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 (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

soils or coastal areas. It feeds chiefly on decaying plant matter, but also grazes

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

s and

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

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 Dormancy is a period in an organism's Biological life cycle, life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolism, metabolic activity and therefore helps an organism to conserv ...

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 Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

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

eastern England Eastern or Easterns may refer to: Transportation Airlines *China Eastern Airlines, a current Chinese airline based in Shanghai * Eastern Air, former name of Zambia Skyways *Eastern Air Lines, a defunct American airline that operated from 192 ...

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

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

, ''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 North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, 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 RosenberPopul ...

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

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

coastal

grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...

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/ cute appearances, inte ...

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 ...

. They do not bite or spread disease to humans.

Mitochondrial genome

Most animals have circular

mitochondrial genomes Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in ...

, 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:A. Vulgare adults.jpg, Solid grey ''A. vulgare'' as adults File:Armadillidium vulgare 001.jpg, Spotted ''A. vulgare'' specimen

References

External links

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