Mushroom snails
| Mushroom snails | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Fungus snail ( Malacolimax tenellus ), on the underside of a lamellar mushroom |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Malacolimax tenellus | ||||||||||||
| ( OV Müller , 1774) |
The mushroom snail ( Malacolimax tenellus ) is a species of nudibranch from the family of the snails (Limacidae) native to Northern and Central Europe in the suborder of the land snails (Stylommatophora). The species is native to Europe with the exception of the Mediterranean region, but in very dispersed occurrences. As the name correctly implies, the animals feed predominantly on mushrooms, the young on mushroom mycelium, and the larger animals on the fruiting bodies of the mushrooms.
features
When fully grown, the mushroom snail reaches a body length of approx. 25 to 40 mm (rarely up to 50 mm or 65 mm). The skin is gelatinous and translucent so you can see the outlines of some of the organs inside the snail. The color of the body varies from whitish, light yellow, lemon yellow, greenish yellow, brownish yellow to orange. The head is usually a little darker, the antennae are brown, dark brown to almost black. The sides can have very weak, somewhat darker lengthways bars. Juvenile animals are still colorless or only slightly yellow. Adult coloring is only achieved after about six months.
The blunt keel is short and limited to the rearmost end of the body. The coat takes up less than 3/4 of the body length. The wrinkles are small and weak. The sole of the foot is clearly divided into three parts, but monochrome yellowish white. The body mucus is yellowish to orange and tough, so tough that the animal sticks to it when touched with a finger. Wiktor (1973), on the other hand, describes the slime as thin. In contrast to body mucus, the foot mucus is colorless.
Like all specimens from the Schnegel family, the mushroom snail also has a small asymmetrical calcareous plate under its mantle shield with a slightly raised nucleus at the rear end.
In the hermaphroditic genital apparatus, the hermaphroditic gland is shortened and rounded. The hermaphroditic duct is long and thin, the protein gland large and white. The penis is short piston-shaped, spherical or cylindrical. The spermatic duct (vas deferens) is very short, runs next to the penis and opens apically into the penis. The penis is elongated like a horn at the mouth. The penile retractor inserts near the apical end and horn-shaped process of the penis. The seminal bag (spermathec) opens into the penis near the transition from the penis to the atrium. It is large and egg-shaped with a short stem. The prostate is fused with the fallopian tube. The fallopian tube gradually widens towards its confluence with the atrium. The atrium itself is very short and small.
In the digestive tract, the first of the three intestinal loops is the largest, the second intestinal loop the shortest. There is no appendix.
Geographical distribution and habitat
The mushroom snail is native to northern, central and eastern Europe. The distribution area extends from Eastern France to European Russia, Ukraine and in the south of the area to Romania (Dobruja). The southern border runs from Romania via Croatia, the southern Alps to the Pyrenees. It is absent in Ireland, Cornwall, north-western Scotland and the islands to the north and west, as well as in northern Scandinavia. However, the occurrences are very scattered.
It mostly lives in old deciduous and coniferous forests, rarely also in old, no longer maintained parks in very shady and damp locations. It also seems to prefer acidic soils and occurs from the plains to the high mountains; in Switzerland up to 2100 m, but usually below 1700 m.
Way of life
During the day, the mushroom snail lives hidden under stones, old leaves, tree trunks and rotten wood. In wet weather, adult animals crawl up smooth tree trunks (e.g. beeches) and eat the lawns of fungi, algae and lichen that grow on the bark. In autumn they prefer to feed on hat mushrooms. Juvenile animals, especially shortly after hatching, live almost exclusively in the upper crust and the leaf litter; they eat mushroom mycelia there. At least in captivity or in laboratory conditions, cannibalism was also observed when there was a lack of food. In feeding experiments they clearly preferred mushrooms, but also accepted green parts of plants and carrots.
Reproduction
The mushroom snail reaches sexual maturity after about 7 to 9 months. Then they have reached a size of 25 mm to 35 mm. Animals less than 25 mm in length are usually not yet sexually mature. Reproduction takes place in Central Europe from October to November.
Copulation begins with a brief pursuit of one animal by another that lasts only a few minutes. Then the pursued animal turns to the right and circles are formed. The heads rise and the two partners gnaw each other. Only a little later, the two partners lie next to each other and turn the right side of the body (with the genital opening) towards each other. The heads turn against each other, but there is no looping. The penes shoot out very suddenly. They swell to form blister-like structures that are bluish in color due to the hemolymph and that press against one another but are only minimally twisted. They adhere to one another through "suction pads", each roughly in the middle of the penis. At the beginning of the copulation, the two of them turn very slowly in a circle. Then the heads are drawn under the coat shield and the partners lie motionless. The combs of the penes unfold slowly and then swell thickly (after about half an hour). After another half an hour, the sperm masses have reached the penis tips. The sperm mass is transferred from penis to penis. After another 20 minutes, the penes begin to swell, the heads are stretched out again and the separation is initiated. The heads pull the penes apart violently. It may take a further 20 minutes until the penes separate from one another and are drawn in, and the animals have finally separated from one another. Copulation takes a total of 1½ to 1¾ hours. In the absence of a partner, the mushroom snail can also reproduce through self-fertilization.
The egg-laying period falls in late autumn and early winter and can last two to three months. Four to six times, 12 to 31 eggs are laid in piles in sheltered, moderately warm places, a total of 87 to 124 eggs. The eggs are ellipsoidal with a size of 4mm × 3mm. Depending on the viscosity of the gelatinous mass in which the eggs are embedded, the eggs are laid individually or as an egg string. The development until hatching takes 20 to 109 days (120 days) depending on the temperature. The young animals are initially colorless when they hatch, with the exception of antennae, cloak shield and tail end, which are slightly violet. With a longer development time (> 100 days) the hatchlings were yellowish. At about six months they have taken on the color of the adults. The animals are fully grown at around ten to eleven months. The animals are 12 to 13 months old.
Taxonomy
The taxon was first scientifically described by Otto Friedrich Müller in 1774. It is the type species of the genus Malacolimax Malm, 1868, which was previously mostly considered a sub-genus of Limax , but is now usually treated as an independent genus.
supporting documents
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
- Michael P. Kerney, RAD Cameron & Jürgen H. Jungbluth: The land snails of Northern and Central Europe. 384 pp., Paul Parey, Hamburg & Berlin 1983 ISBN 3-490-17918-8
- Andrzej Wiktor: The Polish Nudibranchs. 182 p., Monograph Fauny Polski, Polska Akademia Nauk Zakład Zoologii Systematycznej i Doświadczalnej, Warsaw & Kraków 1973.
- Künkel, Karl 1934: On the biology of Limax tenellus Nilsson with special consideration of the copula. Zoological Yearbooks, Department for General Zoology and Animal Physiology, 53: 533-566, Jena & Stuttgart.
Individual evidence
- ↑ Kerney et al. (1983: p. 185/6)
- ↑ a b c Bogon (1990: p. 230)
- ↑ a b Wiktor (1973: pp. 78–81)
- ↑ a b Frömming Ewald 1954: Biology of the Central European Landgastropods. 404 S., Duncker & Humblot, Berlin (pp. 199-200).
- ↑ AnimalBase University of Göttingen, Species summary for Malacolimax tenellus , accessed on October 9, 2012
- ^ Mueller, Otto Friedrich 1774: Vermium terrestrium et fluviatilium, seu animalium infusoriorum, helminthicorum, et testaceorum, non marinorum, succincta historia. Volume alterum. -SI-XXXVI + p. 1–214, Copenhagen & Leipzig, Heineck & Faber. [Online at Biodiversity Heritage Library] (p. 11)
- ↑ Fauna Europaea - genus Malacolimax
