Helix aspersa
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| Helix aspersa (Müller, 1774) |
Helix aspersa (garden snail; syn. Cornu aspersum, Cantareus aspersus[1]) is one of the most well-known of all terrestrial molluscs.
It is native to the Mediterranean region and western Europe, from northwest Africa and Iberia east to Asia Minor, and north to the British Isles. However, it is very widely introduced and naturalised elsewhere in the world.[2][3]
Although this species is edible, it is often regarded as a pest in gardens, especially where it has been accidentally introduced.
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[edit] Description
The adult bears a hard, thin calcareous shell 25–40 mm in diameter and 25–35 mm high, with four or five whorls. The shell is somewhat variable in colour and shade but is generally dark brown or chestnut with yellow stripes, flecks, or streaks.
The body is soft and slimy, brownish-grey, and is retracted entirely into the shell when the animal is inactive or threatened. During dry and cold weather, the aperture of the shell is sealed with a thin membrane of dried mucus which is known as an epiphragm, which helps the snail retain moisture. During times of activity the head and foot emerge. The head bears four tentacles, the upper two of which have eyes, and the lower two of which are smaller, tactile and olfactory sensory structures. The tentacles can be retracted into the head. The mouth is located beneath the tentacles, and contains a chitinous radula which the snail uses to scrape and manipulate food particles.
The snail's muscular foot contracts to move the animal, and secretes mucus to facilitate locomotion by reducing friction against the substrate.[3] It moves at a top speed of 1.3 centimetres per second (47 metres per hour),[4] and has a strong homing instinct, readily returning to a regular hibernation site.[5]
Like other Pulmonata, it is a hermaphrodite, producing both male and female gametes. During a mating session of several hours, two snails exchange sperm and after a few days each will dig a nest in the soil and deposit fertilised eggs in it. The young emerge from the eggs after about two weeks, and take one to two years to reach maturity.[3]
[edit] Ecology
The garden snail is herbivorous and has a wide range of host plants. It damages numerous types of fruit trees, vegetable crops, garden flowers, and cereals.
It is a food source for many other animals, including small mammals, many bird species, lizards, frogs, centipedes, and predatory insects.
There is a variety of snail control measures that gardeners and farmers can take to reduce damage. Traditional pesticides are still in use, as are many less toxic control options such as concentrated garlic or wormwood solutions. Copper metal is repellent to snails. A copper band around the trunk of a tree will prevent snails from reaching the foliage and fruit.
The decollate snail (Rumina decollata) will capture and eat garden snails, so it is sometimes introduced as a biological pest control agent.
[edit] Relationship with humans
The species is an agricultural and garden pest, an edible delicacy, and occasionally a household pet.
In French cuisine, it is known as petit gris, and is served as escargot. The snails are farm-raised or bred as a hobby and enjoyed with garlic butter or cream sauces. Their texture is slightly chewy. The practice of rearing snails for food is known as heliciculture.
Recently, this snail has gained popularity as the chief ingredient in skin creams and gels (crema/gel de caracol) sold within the Latino community and used for wrinkles, scars, dry skin, and acne.
It has been introduced to many regions around the world, including southern Africa, Australia, New Zealand, North America and southern South America.[6] It was introduced to California as a food animal in the 1850s and is now a notorious agricultural pest there, especially in citrus groves. Many areas have quarantines established for preventing the importation of the snail in plant matter.
[edit] Notes
[edit] References
- ^ The Cornu problem (html). The Living World of Mollusks. Retrieved on 2007-03-05.
- ^ Pfleger, V. & Chatfield, J. (1983). A guide to snails of Britain and Europe. Hamlyn, London.
- ^ a b c Arkive: Helix aspersa
- ^ Velocity Measurement Units Conversion
- ^ Attia, J. (2004). Behavioural Rhythms of Land Snails in the Field. Biological Rhythm Research 35: 35-41. Abstract.
- ^ Florida Department of Agriculture and Consumer Services: Helix aspersa
[edit] Sources
- Cranshaw, Whitney. (2004). Garden Insects of North America. Princeton University Press ISBN 0-691-09561-2
[edit] External links
