Little slug
| Little slug | ||||||||||||
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Small slug ( Arion intermedius ) |
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| Scientific name | ||||||||||||
| Arion intermedius | ||||||||||||
| ( Normand , 1852) |
The Arion intermedius ( Arion intermedius ), and hedgehog slug or hedgehog snail called, is a slug from the family of slugs (Arionidae) that the subordination of terrestrial snails is provided (gastropod).
features
The small slug measures about 2 to 2.5 cm when stretched out and belongs to the small species within the genus Arion . It is dark brown, yellow-brown, gray-yellow to whitish in color. Different color variations occur together. The rudimentary case is completely covered by the jacket. It is small and firmly calcified, the top is convex, the bottom almost straight. The head and antennae are usually much darker in color, often dark gray to black. There may be a faint indistinct bandage on the sides of the body and mantle shield. The foot is lined with yellowish-gray to yellow, the row of wrinkles above it is colored white. The sole of the foot is yellow, the body mucus is light yellow. When the small slug shrinks, the wrinkles swell to form small tubercles, giving it a hedgehog-like appearance, which has earned it the second common German name hedgehog slug. In the genital apparatus, the free part of the spermatic duct is relatively short and opens apically into the epiphallus. This is narrow and conical. The inner surface is covered with regularly arranged warts. The sperm library has a large, spherical reservoir with a short stem. This is a little swollen at the base. The atrium is short and about as long as it is wide. It has many, irregular folds on the inside. The genital retractor is attached to the spermathec, the epiphallus, and the mouth of the fallopian tube.
Similar species
The small slug resembles the black slug ( Arion ater ) when stretched out due to its coloring . When contracted, it takes on the characteristic prickly shape that the juvenile forms of the black slug do not show.
Geographical distribution, occurrence
The distribution area of the small slug extends from Iceland , the Faroe Islands and Norway (up to 65 °) across western and central Europe to northern Portugal and Sicily . In Central Europe it is widespread, but relatively rare. In Germany it occurs mainly in the northwest, in the south rather scattered. In contrast, it is common in the British Isles. The eastern border of the distribution runs in western Poland and the Czech Republic. Like many other European nudibranch species, the small slug has been introduced to the temperate zones of other parts of the world.
It prefers to live in mixed and heather forests, alluvial forests, also on lake shores, bushes, hedgerows, in gardens, parks and meadows and lives there under leaves, moss, stones and dead wood. In Switzerland it rises to 900 m above sea level. In England it was also found in open biotopes (meadows) where it lives among the grasses.
Way of life
The small slug feeds mainly on mushrooms. In the Faroe Islands, it has been seen eating rotting sheep dung. But fresh plants are also occasionally eaten. At least under breeding conditions, it was observed that they also ate carrion.
In Central Europe, oviposition begins in July or August and lasts for two months. Up to 10 clutches with around three to ten pieces are placed loosely next to each other under moss. The elliptical eggs measure 2.0 to 2.4 × 1.4 to 1.8 mm and are opaque milk white. They are often very different in size within a clutch, often also from clutch to clutch. The development time is approx. 17 to 30 days, depending on the temperature. Under breeding conditions, some animals were sexually mature after just three months and began to copulate. Under natural conditions, this will only be the case after about seven to nine months. The egg-laying period lasts about two months, after which the animals die.
Under natural conditions, the animals are usually only nine months to one year old; up to 15 months under growing conditions. They show a clear annual cycle. In dry areas, the animals take a summer break, which they spend in self-made nests made of earth particles.
swell
literature
- Klaus Bogon: Land snails biology, ecology, biotope protection. 404 p., Natur Verlag, Augsburg 1990 ISBN 3-89440-002-1
- Rosina Fechter and Gerhard Falkner: molluscs. 287 pp., Munich, Mosaik-Verlag 1990 (Steinbach's Nature Guide 10), ISBN 3-570-03414-3
- Ewald Frömming: Biology of the Central European Landgastropods. 404 p., Duncker & Humblot, Berlin 1954.
- Michael P. Kerney, RAD Cameron, Jürgen H. Jungbluth: The land snails of Northern and Central Europe. 384 pp., Paul Parey, Hamburg and Berlin 1983, ISBN 3-490-17918-8
- Andrzej Wiktor: The nudibranchs of Poland Arionidae, Milacidae, Limacidae (Gastropoda, Stylommatophora) Polska Akademia Zakład Zoologii Systematycznej i Doświadczalnej Monograph Fauny Polski, I, 182 S., Kraków 1973
