Woodlouse

Information about Woodlouse

Woodlice

Porcellio scaber

Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Isopoda
Suborder:	Oniscidea Latreille, 1802

Infraorders and Families

Infraorder Tylomorpha
Tylidae
Infraorder Ligiamorpha
Superfamily Trichoniscoidea
Buddelundiellidae
Trichoniscidae
Superfamily Styloniscoidea
Schoebliidae
Styloniscidae
Titaniidae
Tunanoniscidae
Superfamily Oniscoidea
Bathytropidae
Berytoniscidae
Detonidae
Halophilosciidae
Olibrinidae
Oniscidae
Philosciidae
Platyarthridae
Pudeoniscidae
Rhyscotidae
Scyphacidae
Speleoniscidae
Sphaeroniscidae
Stenoniscidae
Tendosphaeridae
Superfamily Armadilloidea
Actaeciidae
Armadillidae
Armadillidiidae
Atlantidiidae
Balloniscidae
Cylisticidae
Eubelidae
Periscyphicidae
Porcellionidae
Trachelipodidae
incertae sedis (Ligiamorpha)
Dubioniscidae
Hekelidae
Irmaosidae
Pseudarmadillidae
Scleropactidae
Ligiidae
Mesoniscidae

Woodlice (known by many common names; see below) are terrestrial crustaceans with a rigid, segmented, calcareous exoskeleton and fourteen jointed limbs. They form the suborder Oniscidea within the order Isopoda, with over 3,000 known species.

Ecology

Woodlice need moisture because they breathe through gills, called pseudotrachea, and so are usually found in damp, dark places, such as under rocks and logs. They are usually nocturnal and are detritivores, feeding mostly on dead plant matter. Woodlice then recycle the nutrients back into the soil. In artificial environments such as greenhouses where it can be very moist, woodlice may become abundant and damage young plants.

They have a shell-like exoskeleton. As the woodlouse grows, it must progressively shed this shell. The moult takes place in two stages; the back half is lost first, followed two or three days later by the front. Woodlice are the only arthropods to moult in this way, with all others shedding their cuticle in a single process.

A female woodlouse will keep fertilised eggs in a patch on the underside of her body until they hatch into small, pink offspring. The mother then appears to "give birth" to her offspring.

Some species of woodlice are able to roll into a ball-like form when threatened by predators, leaving only their armoured back exposed. This ability, or dominant behavior, explains many of the woodlouse's common names.

Metabolic rate is temperature dependent in woodlice. In contrast to mammals and birds, invertebrates are not "self heating": the external environmental temperature relates directly to their rate of respiration.

They are not generally regarded as a serious household pest as they do not spread disease and do not damage wood or structures, however their presence can indicate dampness problems.

Aquatic isopods

Although woodlice are terrestrial crustaceans, several forms have returned to water. Although most of these are amphibian, some have become truly aquatic.

Examples include some Haloniscus species from Australia (family Scyphacidae), and in the northern hemisphere several species of Trichoniscidae and Thailandoniscus annae (family Styloniscidae). Species for which aquatic life is assumed include Typhlotricholigoides aquaticus (Mexico) and Cantabroniscus primitivus (Spain) ^[1].

Common names

Common names for woodlice vary throughout the English-speaking world. They include: "armadillo bug" ^[2], "cheeselog" (Reading, Berkshire) ^[3], "doodlebug" (also used for the larva of an antlion) ^[4], "pill bug" (usually applied only to the genus Armadillidium) ^[2], "roly-poly" ^[5], "potato bug"^[5], "roll up bug" ^[6], "slater" ^[7] and "sow bug" ^[4]^[5].

United Kingdom

There are 37 native or naturalised species in the United Kingdom, ranging in colour and in size (3–30 mm) of which only five are common: Oniscus asellus (the common shiny woodlouse), Porcellio scaber (the common rough woodlouse), Philoscia muscorum (the common striped woodlouse), Trichoniscus pusillus (the common pygmy woodlouse) and Armadillidium vulgare (the common pill bug).

Pill millipedes

A comparison of the pill millipede Glomeris marginata and isopod Armadillidium

Pill millipedes are often confused with pillbugs (woodlice of the family Armadillidiidae). This is an example of parallel evolution, and pill millipedes can be distinguished from woodlice in several ways, especially that they have two pairs of legs per body segment, instead of one pair like isopods. They also have thirteen body segments rather than eleven, and they are smoother, more like those of normal millipedes in color and style.

Fiction

In To Kill a Mockingbird, the main character Scout pokes a "roly-poly".
In the Pixar film A Bug's Life two supporting characters are acrobatic woodlice, "Tuck" and "Roll", who have their own ride at Disney's California Adventure Park.
The giant creatures called Ohmu in Hayao Miyazaki's Nausicaä of the Valley of the Wind also resemble woodlice.
In the webcomic Wigu, giant woodlice ("slagathors") are infrequently featured. They are forced to run organised races on alien planets.
The Gustav, a mecha from the Zoids franchise, is similar in design to a woodlouse.
In Harry Potter and Order of the Phoenix, woodlice are fed to bowtruckles.
Dink Smallwood includes the woodlouse as an enemy.
In a Rugrats episode, Chuckie Finster kept one as a pet, but it died a few days after. Its name was Melville.
In Salad Fingers (an underground cartoon by David Firth) there was a woodlouse which was tragically flattened when Salad Fingers tried to pet her.
Woodlice are part of the story in the movie Tierra by Julio Medem.
In the film , woodlice (cloportes) are a part of the title, and shots of woodlice appear during the opening credits.
In Lexx, the Gigashadow resembles a gigantic, planet-sized woodlouse. The Lexx logo resembles a rolled-up woodlouse as well.
In Rescue Rangers, Professor Nimnal uses his Giganto Gun to turn pillbugs in to fake aliens for extorting gold as spaceship fuel.

Gallery

''Porcellio scaber (left) and Oniscus asellus (center)

Armadillidium vulgare

Armadillidium vulgare rolled up

Philoscia muscorum

External links

References

1. ^ Ivo Karaman (2003). Macedonethes stankoi n. sp., a rhithral oniscidean isopod (Isopoda: Oniscidea: Trichoniscidae) from Macedonia. Organisms Diversity & Evolution 3 (8): 1-15.
2. ^ Bill Amos (2002-08-10). Little armored tanks. Caledonian-Record.
3. ^ Paul Kerswill. The sound of Reddin. BBC. Retrieved on 2006-09-17.
4. ^ "Sow bug". Dictionary.com Unabridged (v 1.0.1) (2006). Retrieved on 2006-09-17.
5. ^ Bert Vaux & Scott A. Golder. Dialect Survey. Harvard University. Retrieved on 2006-09-30.
6. ^ Gail Smith-Arrants (2004-03-20). You say potato bug, I say roly-poly, you say… (PDF). Charlotte Observer.
7. ^ Maria Minor & A. W. Robertson (2006). Guide to New Zealand soil invertebrates: Isopoda. Massey University. Retrieved on 2007-05-13.

Examples

The taxonomy for humans is usually recognized as follows:

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See also Wikipedia:Naming conventions (common names) and Wikipedia:Naming conventions

In science, a common name is any name by which a species or other concept is known that is not the official scientific name.
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An exoskeleton is an external anatomical feature that supports and protects an animal's body, in contrast to the internal endoskeleton of, for example, a human. Whilst many many other invertebrate animals (such as shelled mollusks) have exoskeletons in the sense of external hard
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A gill is a respiration organ that functions for the extraction of oxygen from water and the excretion of carbon dioxide. Unlike many small aquatic animals, which can absorb oxygen through the entire surface of their bodies, more complex aquatic organisms have gills specially
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nocturnality describes sleeping during the daytime and being active at night - the opposite of the diurnal human lifestyle, and that of those animals with which we are most familiar. The intermediate crepuscular schedule (twilight activity) is also common.
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Detritivores (also known as detrivores or detritus feeders) are animals that consume detritus (decomposing organic material), and in doing so contribute to decomposition and the recycling of nutrients.
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shell is a hard, rigid outer layer, which has evolved in a very wide variety of different animals, including mollusks, sea urchins, crustaceans, turtles and tortoises, armadillos, etc.
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Ecdysis is the moulting of the cuticula in arthropods and related groups (Ecdysozoa). Since the cuticula of these animals is also the skeletal support of the body and is inelastic, it is shed during growth and a new, larger covering is formed. The old skin is called an exuvia.
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Fertilization (also known as conception, fecundation and syngamy), is fusion of gametes to form a new organism of the same species. In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo.
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In most birds and reptiles, an egg (Latin ovum) is the zygote, resulting from fertilization of the ovum. To enable incubation the egg is usually kept within a favourable temperature range as it nourishes and protects the growing embryo.
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Metabolism is the complete set of chemical reactions that occur in living cells. These processes are the basis of life, allowing cells to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories.
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