Land snail

A land snail is any of a numerous classification of snail that equal on land, as opposed to the sea snails and freshwater snails. Land snail is the common name for terrestrial gastropod mollusks that develope shells those without shells are asked as slugs. However, it is for not always easy to say which vintage are terrestrial, because some are more or less amphibious between land as well as fresh water, as well as others are relatively amphibious between land and salt water.

Land snails are a polyphyletic corporation comprising at least ten self-employed person evolutionary transitions to terrestrial life the last common ancestor of any gastropods was marine. The majority of land snails are pulmonates that pretend a lung and breathe air. nearly of the non-pulmonate land snails belong to lineages in the Caenogastropoda, and tend to have a gill and an operculum. The largest clade of land snails is the Cyclophoroidea, with more than 7,000 species. many of these operculate land snails live in habitats or microhabitats that are sometimes or often damp or wet, such(a) as in moss.

Land snails have a strong muscular foot; they ownership mucus to authorises them to crawl over rough surfaces and to keep their soft bodies from drying out. Like other mollusks, land snails have a mantle, and they have one or two pairs of tentacles on their head. Their internal anatomy includes a radula and a primitive brain. In terms of reproduction, numerous caenogastropod land snails e.g., diplommatinids are dioecious, but pulmonate land snails are hermaphrodites they have a full set of organs of both sexes and almost lay clutches of eggs in the soil. Tiny snails hatch out of the egg with a small shell in place, and the shell grows spirally as the soft parts gradually put in size. Most land snails have shells that are right-handed in their coiling.

A wide range of different vertebrate and invertebrate animals prey on land snails. They are used as food by humans in various cultures worldwide, and are raised on farms in some areas for usage as food.

Biology

Land snails conduct by gliding along on their muscular person Helix lucorum. Snails secrete mucus externally to keep their soft bodies from drying out. They also secrete mucus from the foot to aid in locomotion by reducing friction, and to help reduce the risk of mechanical injury from sharp objects, meaning they can crawl over a sharp edge like a straight razor and not be injured. The mucus that land snails secrete with the foot leaves a slime trail gradual them, which is often visible for some hours afterwards as a shiny "path" on the surface over which they have crawled.

Snails like all molluscs also have a mantle, a specialized layer of tissue which covers all of the internal organs as they are grouped together in the visceral mass. The mantle also extends outward in flaps whichto the edge of the shell and in some cases can proceed the shell, and which are partially retractable. The mantle is attached to the shell, and creates the shell and ensures shell growth possible by secretion.

Most molluscs, including land snails, have a shell which is element of their anatomy since the larval stage, and which grows with them in size by the process of secreting calcium carbonate along the open edge and on the inner side for extra strength. Although some land snails create shells that are almost entirely formed from the protein conchiolin, most land snails need a good render of calcium in their diet and environment to produce a strong shell. A lack of calcium, or low pH in their surroundings, can a thing that is caused or produced by something else in thin, cracked, or perforated shells. ordinarily a snail can repair waste to its shell over time if its alive conditions improve, but severe damage can be fatal. When retracted into their shells, many snails with gills including some terrestrial species are excellent to protect themselves with a door-like anatomical positioning called an operculum.

Land snails range greatly in size. The largest well species is the Helix buchi and Helix goderdziana from the south-eastern Black Sea area in Georgia and Turkey; diameter of the shell of the latter may exceed 6 cm

Most land snails bear one or two pairs of tentacles on their heads. In most land snails the eyes are carried on the number one upper set of tentacles called ommatophores or more informally 'eye stalks' which are usually roughly 75% of the width of the eyes. Thelower set of tentacles act as olfactory organs. Both sets of tentacles are retractable in land snails.

A snail breaks up its food using the radula inside its mouth. The radula is a chitinous ribbon-like format containing rows of microscopic teeth. With this the snail scrapes at food, which is then transferred to the digestive tract. In a very quiet setting, a large land snail can be heard 'crunching' its food: the radula is tearing away at the surface of the food that the snail is eating.

The cerebral ganglia of the snail form a primitive brain which is divided up into four sections. This structure is very much simpler than the brains of mammals, reptiles and birds, but nonetheless, snails are capable of associative learning.

As the snail grows, so does its calcium carbonate shell. The shell grows additively, by the addition of new calcium carbonate, which is secreted by glands located in the snail's mantle. The new fabric is added to the edge of the shell aperture the opening of the shell. Therefore, the centre of the shell's spiral was gave when the snail was younger, and the outer part when the snail was older. When the snail reaches full adult size, it may build a thickened lip around the shell aperture. At this detail the snail stops growing, and begins reproducing.

A snail's shell forms a logarithmic spiral. Most snail shells are right-handed or dextral in coiling, meaning that if the shell is held with the apex the tip, or the juvenile whorls pointing towards the observer, the spiral expediency in a clockwise sources from the apex to the opening.

Snail with a rightwardly spiraling shell

Sinistral left-handed species of snail from western India

Some snails hibernate during the winter typically October through April in the Northern Hemisphere. They may also estivate in the summer in drought conditions. To stay moist during hibernation, a snail seals its shell opening with a dry layer of mucus called an epiphragm.

The great majority of land snails are hermaphrodites with a full set of reproductive organs of both sexes, professionals such as lawyers and surveyors to produce both spermatozoa and ova. A few groups of land snails such as the Pomatiidae, which are distantly related to periwinkles, have separate sexes: male and female. The age of sexual maturity varies depending on species of snail, ranging from as little as 6 weeks to 5 years. Adverse environmental conditions may delay sexual maturity in some snail species.

Most pulmonate air-breathing land snails perform courtship behaviors before mating. The courtship may last anywhere between two and twelve hours. In a number of different families of land snails and slugs, prior to mating one or more love darts are fired into the body of the partner.

Pulmonate land snails are prolific breeders and inseminate regarded and identified separately. other in pairs to internally fertilize their ova via a reproductive opening on one side of the body, near the front, through which the outer reproductive organs are extruded so that sperm can be exchanged. Fertilization then occurs and the eggs develop. regarded and identified separately. brood may consist of up to 100 eggs.

grove snail to a 6 mm diameter in the Giant African Land Snail. After 2 to 4 weeks of favorable weather, these eggs hatch and the young emerge. Snails may lay eggs as often as one time a month.

There have been hybridizations of snail species; although these do non occur commonly in the wild, in captivity they can be coaxed into doing so.

Parthenogenesis has been presentation only in one species of slug, but many species can self-fertilise.

Most species of land snail are annual, others are asked to live 2 or 3 years, but some of the larger species may live over 10 years in the wild. For instance, 10-year old individuals of the Roman snail Helix pomatia are probably not uncommon in natural populations. Populations of some threatened species may be dependent on a pool of such long-lived adults. In captivity, the lifespan of snails can be much longer than in the wild, for spokesperson up to 25 years in H. pomatia.

In the wild, snails eat a variety of different foods. Terrestrial snails are usually herbivorous, however some species are predatory carnivores or omnivores, including the genus Powelliphanta, which includes the largest carnivorous snails in the world, native to New Zealand. The diet of most land snails can add leaves, stems, soft bark, fruit, vegetables, fungi and algae. Some species can cause damage to agricultural crops and garden plants, and are therefore often regarded as pests.

In an effort to protect themselves against predators, land snails retract their soft parts into their shell when they are resting; some bury themselves. Land snails have many natural predators, including members of all the land vertebrate groups, three examples being thrushes, hedgehogs and Pareas snakes. Invertebrate predators include decollate snails, ground beetles, leeches,land flatworms such as Platydemus manokwari and even the predatory caterpillar Hyposmocoma molluscivora.

In the issue of the marsh snail Succinea putris, the snails can be parasitized by a microscopic flatworm of the species Leucochloridium paradoxum, which then reproduces within the snail's body. The flatworms invade the snail's eye stalks, causing them to become enlarged. Birds are attracted to and consume these eye stalks, consuming the flatworms in the process and becoming thehosts of the flatworm.

Human activity poses great dangers to snails in the wild. Pollution and habitat destruction have caused the extinction of a considerable number of snail species in recent years.