Common snail snail
| Common snail snail | ||||||||||||
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Common snail snail ( Bithynia tentaculata ) |
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| Scientific name | ||||||||||||
| Bithynia tentaculata | ||||||||||||
| ( Linnaeus , 1758) |
The Common bithyniidae ( Bithynia tentaculata ) is a freshwater snail from the family of bithyniidae (Bithyniidae) that the order of Caenogastropoda is provided. It is widespread in Europe.
features
The housing is highly conical and has 5.5 turns that increase relatively quickly. They are moderately arched and separated from one another by a clear seam. The housing is up to 11 mm high and has a max. Thickness or width of 8 mm. The navel is usually not visible. The mouth is approximately oval, but pointed at the upper end. The operculum fits exactly into the mouth and is built concentrically around a core. The body is dark with yellow flecks
Way of life
The animals are usually 12 to 27 months old. Presumably a small part of the population survives another winter and is therefore somewhat larger than the rest of the population ( Bithynia tentaculata f. Producta ). After mating, the female lays 20 to 40 eggs on stones or some other hard surface, which are arranged in spawning lines of three eggs in a transverse row. The young hatch after 14 to 20 days, depending on the water temperature. The development of the eggs takes place at temperatures between 13 and 26 ° C. The animals live in stagnant or poorly flowing waters. They feed as grazers and detritus filter feeders . The filtering way of life predominates.
distribution
The species is distributed throughout Europe with the exception of northern Scandinavia and Greece. In the east the distribution area extends to western Siberia. In large parts of Central Europe, the common snail snail is one of the most common freshwater snails. It was abducted to the Great Lakes in the 1870s and is now found in large parts of North America.
Saprobic index
The saprobic index of this type is 2.3, but is not without controversy: The worm comes mostly in the waters of grade II to II - before, but is also critically polluted waters of grade encountered III.
Systematics
Several forms are distinguished, but their status is unclear.
- Bithynia tentaculata f. codia (occurrence: pre-alpine lakes )
- Bithynia tentaculata f. gigas (occurrence: Denmark and Sweden)
- Bithynia tentaculata f. excavata (occurrence: Great Britain, Denmark and Sweden)
- Bithynia tentaculata f. bottnica (Occurrence: Sweden)
- Bithynia tentaculata f. producta (occurrence: in the distribution area of the species)
literature
- Peter Glöer: The animal world of Germany. Mollusca I Freshwater gastropods of Northern and Central Europe Key to identification, way of life, distribution. 2. rework. Ed., 327 pages, ConchBooks, Hackenheim 2002 ISBN 3-925919-60-0
- Rosina Fechter and Gerhard Falkner: molluscs. 287 pp., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10) ISBN 3-570-03414-3
Web links
Individual evidence
- ↑ Jennifer S. Sauer, Rebecca A. Cole and James M. Nissen: Finding the Exotic Faucet Snail (Bithynia tentaculata): Investigation of Waterbird Die-Offs on the Upper Mississippi River National Wildlife and Fish Refuge. (PDF; 1.52 MB) PDF
- ↑ Meyer, Detlef .: Macroscopic biological field methods for assessing the water quality of rivers: with lists of species for beginning and experienced investigators and detailed descriptions and images of the indicator organisms . 4th, unchanged. BUND, Hannover 1990, ISBN 3-9800871-4-X .