Woodlice feed on dead organic matter, which they detect by means of taste and smell (2). During the breeding season, reproductive females develop a 'brood pouch', which consists of overlapping leaf-like structures known as 'oostegites', that form a 'false floor' below the body. The fertilised eggs pass into this fluid-filled chamber, and the young crawl out of the brood pouch when they are fully developed. Woodlice undergo a series of moults before reaching maturity, growing at each stage; the stages between these moults are known as 'stadia', and are generally similar in structure and appearance. Mature woodlice continue to moult. Prior to moulting, the calcium contained in the old cuticle is removed and stored as conspicuous white blotches, these blotches disappear after moulting as the calcium is used to reinforce the new cuticle (2). The rear part of the body moults a few days before the front half, and occasionally woodlice may be seen with half a pinkish body and half a 'usual' grey body for this reason (4). The discarded cuticle is frequently eaten by the newly moulted woodlouse (2).

Woodlice are not insects, but are crustaceans; more closely related to crabs and shrimps than insects. The body is divided into three main regions, the head, the thorax (known in woodlice as the 'pereion'), and the abdomen ('pleon') (2). The pill woodlouse is so called because it is able to roll into a ball when threatened; it is often confused with the pill millipede (Glomeris marginata) for this reason (3). This woodlouse is typically slate grey in colour, but red or patchy forms may arise (2).

You have probably seen them in your basement or garden, for they live under stones and bark in damp places. While they exist in large numbers here in North America, they also reside in the wettest areas of Germany.

Biogeographic Regions: nearctic (Native ); palearctic (Native )

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

This species is very common in the south-east of England, is found in parts of western and northern England and becomes rare in Scotland (2).

Their light shell-like crustaceous exterior is usually a drab earthy color. Pill bugs found in North America range from gray to brown. However, those with habitats in Europe have large red dots, which give them protection by conferring a resemblance to black widow spiders. Pill bugs have five abdominal segments which are distinct dorsally. Their first antennae are vestigial.

Pill bugs hide in damp places during the day and are active at night. Under moist areas such as bark and stones, they make their burrow (living quarters.) One of the pill bugs' most surprising characteristics is that they have such a wide distribution pattern. "Home" can be a forest, garden, or basement.

Terrestrial Biomes: savanna or grassland ; forest

Depth range based on 2 specimens in 4 taxa.

Environmental ranges
  Depth range (m): 229 - 1646

Graphical representation

Depth range (m): 229 - 1646
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Habitat Type: Terrestrial

Occurs only on calcareous soils, except in coastal areas (2), and is able to withstand much drier conditions than most other woodlice (3). It shows a distinct preference for chalky or limestone sites with stony turf (2).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

A. vulgare, like most isopods, are omnivorous. They feed on fungi, live or dead plants and animals. Special treats for pill bugs are monocotyledonous leaves. All isopods increase decomposition by processing leaves through their alimentary canal. It is not uncommon for pill bugs to shift from one type of food to another, for during a drought they turn from being vegetarians into scavengers.

Primary Diet: carnivore (Scavenger ); herbivore (Folivore , Frugivore ); mycophage ; detritivore

These animals are part of the community of species that break down dead plants and animals.

Ecosystem Impact: biodegradation

Mutualist Species:

• Pillbugs and sowbugs have microbes in their guts that allow the crustacean to digest plant material.

They are famous for curling up into a tight ball for a defense mechanism. Some may secrete a substance which discourages spiders. The most common defense among all of them is to remain inconspicuous.

Known Predators:

• centipedes
• spiders
• ants
• birds
• amphibians
• anything that eats invertebrates

Animal / parasite / endoparasite
Prosthorhynchus formosus endoparasitises Armadillidium vulgare

A. vulgare reproduce on land as opposed to in water. Eggs develop in a brood pouch filled with fluid, from which fully developed young are released. They produce between one and two broods. The number produced depends on the size and condition of the female, who may cease to grow under stress due to excessive hydration, which reduces the chance of a second reproduction. Ironically, when the food supply is short, the offspring grow larger.

The following is a representative barcode sequence, the centroid of all available sequences for this species. 

 
There is 1 barcode sequence available from BOLD and GenBank.   Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen.  Other sequences that do not yet meet barcode criteria may also be available.
 

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Species: 6
Species With Barcodes: 1

Pill bugs are quite common and have no special conservation status.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: GNR - Not Yet Ranked

Common and widespread (1).

Not currently threatened.

Conservation action has not been targeted at this common species.

Pillbugs may occasionally eat small plants as they germinate, causing some trouble in gardens.

Pill bugs living in gardens help circulate soil, although they may also eat small plants.