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For other uses, see Slug (disambiguation).
Various species of land slugs
Various species of land slugs

Slug is a common non-scientific word which is most often applied to any gastropod mollusk whatsoever that has a very reduced shell, a small internal shell, or no shell at all. The class Gastropoda or the gastropods, also previously known as gasteropods, or univalves, and more commonly known as Snails Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000 A slug-like body is an adaptation which has occurred many times in various groups of snails. The word snail is a Common name that can be used for almost all members of the Molluscan class Gastropoda which have coiled shells in the

The common name "slug" is most often applied to land species, but the word has also been applied to many marine species. For Wikipedia aspects see WikipediaNaming conventions (common names, WikipediaNaming conventions, and WikipediaStyle manual. The largest group of marine shell-less gastropods or sea slugs are the nudibranchs, but there are in addition many other groups of sea slug such as the heterobranch sea butterflies, sea angels, and sea hares, as well as the only very distantly related, pelagic, caenogastropod sea slugs, which are within the superfamily Carinarioidea. A nudibranch (pronounced (BrE or (AmE is a member of one Suborder of soft-bodied shell-less marine Opisthobranch Gastropod Mollusks Sea butterflies, also known as Thecosomata or flapping Snails, are a Taxonomic suborder of Pelagic swimming sea snails Sea angels, also known as cliones, and previously known as one kind of Pteropod, are a group of small swimming sea Slugs. Sea hares ( Aplysia species and related genera are very large sea Slugs with a soft internal shell made of protein

Evolutionarily speaking, the loss or reduction of the shell in gastropods is a derived characteristic; the same basic body design has independently evolved several times, making slugs a strikingly polyphyletic group. In Phylogenetics, a Taxon is polyphyletic ( Greek for "of many races" if the trait its members have in common evolved separately in different In other words, the shell-less condition has arisen many times in the evolutionary past, and because of this, the various different taxonomic families of slugs are often not at all closely related to one another, despite a superficial similarity.

This article is primarily about pulmonate land slugs. The Pulmonata or "pulmonates" are an order (once a Subclass) of Snails and Slugs that have developed a pallial Lung

Contents

Land slugs

Although land slugs have undergone torsion (180º twisting of the internal organs) during development, their bodies are streamlined and worm-like, and so externally they show only a little evidence of this asymmetry, and that mainly in the positioning of the pneumostome. Torsion is a Gastropod Synapomorphy which occurs in all gastropods during Larval development Asymmetry is the absence of or a violation of a Symmetry. In organisms Due to how cells divide in Organisms asymmetry in organisms is pneumostome is a feature (the respiratory opening of the external body anatomy of an air-breathing land slug or land snail

The soft, slimy bodies of slugs are prone to desiccation, so land-living slugs are confined to moist environments. Desiccation is the state of extreme dryness or the process of extreme drying

Morphology and behaviour

Anatomy of a slug
Anatomy of a slug

Slugs macerate food using their radula, a rough, tongue-like organ with many tiny tooth-like denticles. The radula is a toothed Chitinous ribbon typically used for scraping cutting and chewing food before it enters the Esophagus. Denticles are body surface structures found on some fish and insects

Like snails, most slugs have two pairs of 'feelers' or tentacles on their head; the upper pair being light sensors, while the lower pair provides the sense of smell. A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument Olfaction (also known as olfactics or smell) refers to the Sense of smell. Both pairs are retractable and can be regrown if lost. On top of the slug, behind the head, is the saddle-shaped mantle, and under this are the genital opening and anus. The mantle is an important part of the anatomy of Molluscs It is the dorsal body wall which covers the visceral mass The mantle also has a hole, the pneumostome, for respiration. pneumostome is a feature (the respiratory opening of the external body anatomy of an air-breathing land slug or land snail The slug moves by rhythmic muscular action of its foot.

Some species hibernate underground during the winter in temperate climates, but in other species, the adults die in the autumn.

Mucus

Slugs' bodies are made up mostly of water and are prone to desiccation. They must generate protective mucus to survive. In drought conditions they hide under fallen logs, rocks, plants, and planters in order to help retain body moisture.

Slugs produce two types of mucus: one which is thin and watery, and another which is thick and sticky. In vertebrates mucus is a slippery secretion produced by and covering Mucous membranes It is a viscous Colloid containing Antiseptic enzymes (such as Both are hygroscopic. Hygroscopy is the ability of a substance to attract Water Molecules from the surrounding environment through either absorption or Adsorption The thin mucus is spread out from the centre of the foot to the edges. The thick mucus spreads out from front to back.

Mucus is very important to slugs because it helps them move around, and contains fibres which prevent the slug from sliding down vertical surfaces. Mucus also provides protection against predators and helps retain moisture. Some species use slime cords to lower themselves on to the ground, or to suspend a pair of slugs during copulation.

Reproduction

Slugs are hermaphrodites, having both female and male reproductive organs. A hermaphrodite is an organism having both male and female reproductive organs Once a slug has located a mate they encircle each other and sperm is exchanged through their protruding genitalia. A few days later around 30 eggs are laid into a hole in the ground or under the cover of objects such as fallen logs.

A commonly seen practice among many slugs is apophallation, when one or both of the slugs chews off the other's penis . The penis of these species is curled like a cork-screw and often becomes entangled in their mate's genitalia in the process of exchanging sperm. When all else fails, apophallation allows the slugs to separate themselves. Once its penis has been removed, a slug is still able to participate in sex subsequently, but only using the female parts of its reproductive system.

Ecology

Arion lusitanicus feeding on leaves.
Arion lusitanicus feeding on leaves. The Spanish slug, more commonly known in English -speaking countries under its Latin name Arion lusitanicus, is a highly invasive slug species

Many species of slugs play an important role in ecology by eating dead leaves, fungus, and decaying vegetable material. In Botany, a leaf is an above-ground Plant organ specialized for Photosynthesis. A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Some slugs are predators. Most slugs will also eat carrion including dead of their own kind.

Predators

Frogs, toads, snakes, hedgehogs, Salamanders, eastern box turtles, humans and also some birds and beetles are natural slug predators. This article is about the block cipher algorithm For the ultrafast laser pulse measurement technique see Frequency-resolved optical gating. A toad can refer to a number of Species of Amphibians in the order Anura. A snake is an elongate Reptile of the suborder Serpentes Like all reptiles snakes are covered in scales. A hedgehog is any of the small spiny Mammals of the Subfamily Erinaceinae and the order Erinaceomorpha. Salamander (orig from Persian: sām, "fire" and andarūn, "within" is the common name for a group of approximately 500 Species The Eastern Box Turtle ( Terrapene carolina carolina) is a Subspecies within a group of Hinge -shelled turtles normally called Box turtles Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Slugs, when attacked, can contract their body, making themselves harder and more compact and thus more difficult for many animals to grasp. The unpleasant taste of the mucus is also a deterrent.

Human relevance

A small number of species of slugs feed on fruits and vegetables prior to harvest, making holes in the crop that makes it more vulnerable to rot and disease, and making individual items unsuitable to sell. Slugs such as Deroceras reticulatum are a serious pest to agriculture. Deroceras reticulatum, Common names "grey field slug" and "grey garden slug" is a Species of small air-breathing land Slug Pesticides are used in large-scale agriculture, while small home gardens may use slug tape as a deterrent to keep slugs out of crop areas. Copper tape refers to an Adhesive Copper tape. Copper tape is also marketed as slugit to keep Slugs and Snails out of certain

In a few cases, humans have contracted parasite-induced meningitis from eating raw slugs [1]. Meningitis is Inflammation of the protective membranes covering the Brain and Spinal cord, known collectively as the Meninges.

Sammy the slug.
Sammy the slug.

The banana slug, Ariolimax dolichophallus, is the mascot of the University of California at Santa Cruz.

Photographs

Red slug, Arion rufus - red color form on a rhubarb leaf, in England

Banana slug, Ariolimax columbianus, Univ. The red slug, also known as the chocolate arion or the European red slug, Arion rufus, is a large land Slug, a terrestrial Banana slugs are any Species of the pulmonate Gastropod Genus Ariolimax, (literally " Arion 's slug" of Calif. Santa Cruz

Great grey slug, Limax maximus, in Illinois, USA

Two Great grey slugs mating

Tropical leatherleaf, Laevicaulis alte

A slug from North Bend, Washington, USA

A slug from the Western Ghats of India

A slug found in Hampshire, England, feeding on a leaf. The Great Grey Slug, Limax maximus (literally "great slug" also known as the Tiger slug or the Spotted leopard slug, is one of the The State of Illinois ( roughly ill-i-NOY is a state of the United States of America, the 21st to be admitted to the Union. The Great Grey Slug, Limax maximus (literally "great slug" also known as the Tiger slug or the Spotted leopard slug, is one of the The tropical leatherleaf, Laevicaulis alte, is a Species of tropical Slug, a terrestrial Pulmonate Gastropod Washington ( is a state in the Pacific Northwest region of the United States. The Western Ghats ( Kannada ಸಹ್ಯಾದ್ರಿ Marathi / Konkani - सह्याद्री Sahyadri Malayalam സഹ്യപര്‍വ്വതം India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Wildlife Hampshire has wildlife typical of the island of Great Britain England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland

Close up of mating Great Grey Slug found in Maryland, USA

Mating Great Grey Slug found in Maryland, USA

Great Grey Slug pictured in Maryland, USA

Subinfraorders, superfamilies, and families

References

  1. ^ Health and Medicals News - Man's brain infected by eating slugs. The Punctoidea are a Superfamily of air-breathing land snails and slugs terrestrial Gastropod Mollusks This superfamily is in the Rhytididae is a Taxonomic family of medium-sized Predatory air-breathing land Snails Carnivorous terrestrial For the 19th century chemist by the same name see Johannes Thiele (chemist. John Edward Gray ( 12 February 1800 &ndash 7 March 1875) was a British zoologist. For the 19th century chemist by the same name see Johannes Thiele (chemist. Zonitidae, Common name the true glass snails, are a family of mostly rather small air-breathing land Snails terrestrial Pulmonate Retrieved on 2006-03-15. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 44 BC - Julius Caesar, Dictator of the Roman Republic, is stabbed to death by Marcus Junius Brutus,

External links

Dictionary

slug

-noun

  1. Any of many terrestrial pulmonate gastropod mollusks, having no (or only rudimentary) shell
  2. (physics, rarely used) the Imperial (English) unit of mass that accelerates by 1 foot per second squared (1 ft/s²) when a force of one pound-force (lbf) is exerted on it.
  3. A discrete quantity of one fluid that flows though the line surrounded by another.
  4. A bullet.
  5. A counterfeit coin, especially one used to steal from vending machines.
  6. A shot of a drink, usually alcoholic.
  7. A title, name or header
  8. (slang) A lazy person, a sluggard.
  9. (television editing) A black screen.
  10. (typesetting) A piece of typemetal imprinted by a Linotype machine; also a black mark placed in the margin to indicate an error.
  11. (regional) A stranger picked up as a passenger to enable legal use of high occupancy vehicle lanes.

-verb

  1. To drink quickly; to gulp.
  2. To down a shot.
  3. (transitive) To hit very hard.
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