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More About Slugs and Snails ...
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Slugs are gastropods without or with very small shells, in contrast with snails, which have a prominent shell. Although they undergo torsion during development, their bodies are streamlined and worm-like, and so show little external evidence of it. This same basic design developed independently in several different groups, the largest being the sea slugs or nudibranchs. Other slugs are found on land, but their soft, slimy bodies are prone to dessication, so they are confined to moist environments. Some are notable garden pests. Among the various species are the grey field slug, Deroceras reticulatus, the garden slug, Arion hortensis and the banana slug, Ariolimax columbianus.
Various methods exist for controlling these pests. Commercial slug pellets containing metaldehyde or methiocarb are available, but are not approved for organic gardening as they can poison creatures further up the food chain. Aluminium sulphate can also be used and its proponents say that it is less toxic to the environment. Salt will cause a slug to dry out, but this is probably cruel to the slug and also washes away easily.
Slugs have an aversion to copper. Copper pipe can be used and commercial slug rings are available. A six inch (15 cm) length of plastic pipe with copper foil tape stuck round it can be used to protect individual plants. Slugs also find rough surfaces such as crushed eggshells irritating.
Beer traps can be used to drown slugs. Put a jar containing half an inch of beer (12 mm) into a hole in the ground. The slugs will be attracted to the beer and will drown.
Comfrey can be used as a decoy. Put comfrey leaves round plants that need protecting. The slugs will eat the comfrey and leave the protected plant alone. (This is the honeypot approach.)
Frogs and hedgehogs, also some birds and beetles are natural slug predators. Encouraging these creatures will help to keep the slug population under control. Nematodes are parasites that can be used to kill slugs.
Snails
The name snail applies to most members of the molluscan Class Gastropoda that have coiled shells. Other gastropods, which lack a conspicuous shell, are commonly called slugs, and are scattered throughout groups that primarily include snails. Snails are found in freshwater, marine, and terrestrial environments.
Snails move like worms by alternating body contractions with stretching, with a proverbially low speed (hence the term snail mail for postal services). They produce a slime in order to aid locomotion by reducing friction. The slime also reduces the snail's risk of injury and helps keep away potentially dangerous insects like ants. When retraced into their shells, snails cover the entrance with a 'trapdoor' like structure called an operculum.
In winter some snail species hibernate in their shells by closing the opening with a thin shell-like plate that they build only for this use and destroy in spring. Even some slug species build a shell-like object below their upper skin.
Snails come in a range of different sizes. The largest land snail is the Giant African Snail (Achatina fulica; Family Achatinidae), which can measure up to 30cm. Pomacea maculata (Family Ampullariidae), or Giant Apple Snail is the largest freshwater snail, with its size reaching 15 cm diameter and over 600 g weight. The biggest of all snails is Syrinx aruanus, a marine species living in Australia. Shell lengths up to 1 m have been reported.
Snail shells, like those of the Nautilus, are an example of the appearance of the phi, the golden ratio, in nature.
As one of the largest classes of animals, snails can be found throughout the world. They are found in freshwater, marine, and terrestrial environments. The majority of the world's snails live in the oceans and new species are being discovered regularly. Terrestrial snails prefer damp areas around vegetation which they can use for cover during the day.
A snail's diet varies by species. Terrestrial snails such as garden snails generally eat young plant shoots or bark, or decaying vegetative matter. Carnivorous snails, such as the Decollate Snail feed on other snails. Snails eat by using their radula, or scraping tongue, to shear their food.
Snails, like many worms, are hermaphrodites, producing both sperm and eggs. Prolific breeders, snails exchange sperm with one another to fertilize their eggs. Each brood may consist of up to 100 eggs.
Garden snails bury their eggs in shallow topsoil primarily while the weather is warm and damp. After 2 to 4 weeks of favorable weather, these eggs hatch and the young emerge. Snails may lay eggs as often as once a month
Snails have many natural predators, including ground beetles, snakes, toads, turtles, and birds like chickens, ducks and geese. Snails are also eaten by people in several countries of Europe, where they are considered a delicacy. Snails as a food are commonly referred to by the French word escargot. The two commonly eaten species are the Burgundy snail (Helix pomatia) and the brown garden snail (Helix aspersa) also known as the European brown snail.
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Source: Wikipedia Read more about Slugs and Snails
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