Armadillidium

Armadillidium
Armadillidium vulgare
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Isopoda
Suborder:	Oniscidea
Family:	Armadillidiidae
Genus:	Armadillidium Brandt, 1833
Diversity
about 200 species

Armadillidium is a genus of the small terrestrial crustacean known as the woodlouse. Armadillidium are also commonly known as "pill woodlice", "pill bugs," "potato bugs" or "roly-polies", and are often confused with pill millipedes such as Glomeris marginata. They are characterised by their ability to roll into a ball when disturbed. They typically feed on moss, algae, bark and other decaying organic matter. They are usually found in moist areas such as decomposing leaf matter and soil.

The colouration especially of young A. klugii resembles the red hourglass marking of the Mediterranean black widow Latrodectus tredecimguttatus. This is probably a kind of mimicry, to ward off predators that mistake the harmless animal for a venomous spider.

Unlike other arthropods such as insects and spiders, pill bugs do not have a waxy cuticle that would reduce evaporation from their bodies. Pill bugs also use modified gills, called pseudotrachea, for respiration, and the gills must remain moist to function. Individual pill bugs typically live for two or three years, and females brood eggs once or twice each summer. Several hundred eggs are brooded at a time in the marsupium, a pocket on the ventral side of the female pill bug. The marsupium must also be kept filled with water until the young hatch and crawl away.

Some species of Armadillidium are: A. Affine A. Armeniense A. Brevicaudatum A. Cinereum A. Commutattum A. Decipiens A. Marmoreum A. Nitidulum A. Oliveti A. Pilulare A. Schellenbergi A. Sorattinum A. Subdentatum A. Triviale A. Variegatum

Gallery

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  Armadillidium vulgare
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  Wandering Armadillidium vulgare
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  Armadillidium vulgare partially rolled up
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  Armadillidium vulgare rolled up in a ball