Duck leech
| Duck leech | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Theromyzon tessulatum | ||||||||||||
| ( OV Müller , 1774) |
The duck leech ( Theromyzon tessulatum ) is a species from the subclass of leeches (Hirudinea).
features
The duck leech reaches a length of 15 centimeters. He has 4 pairs of eyes one behind the other. The back has a greenish-gray to brownish-gray color and 4 longitudinal rows of yellow spots.
Occurrence and way of life
The duck leech's habitat is stagnant water. The species appears almost cosmopolitan. It sucks blood from waterfowl. Sometimes it penetrates into the pharynx to do this.
Life cycle
Duck leeches are around 1 to 2 years old. Like all leeches, duck leeches are hermaphrodites that mate in April, May or June. To do this, they wrap around each other and perform a longer act of mating in which pseudospermatophores - unlike most flat cones - are transferred into the female genital opening. In the partner rule, the sperm leave the pseudospermatophore and swim to the egg cells. Around 10 days after mating, up to 200 fertilized eggs are laid in 2 to 5 pear-shaped cocoons - in one up to 80 eggs - in May, June or July, which are formed by the clitellum and attached to the base. The mother incubates the eggs in the cocoons until small leeches hatch and attach themselves to the mother's belly with their rear suction cup. The mother, who no longer eats anything herself, is now looking for a host and attaches herself to his pharynx. The young animals change their place from their mother to the pharyngeal mucous membrane of the waterfowl, where they have their first blood meal in large numbers and are now on their own. The young animals stay with their mother for up to a month and a half. If this does not find a host, it is often eaten by a water bird. The young attach themselves to the throat of the bird that is eating the mother and in this way come to their first host.
Medical importance
From the saliva of Entenegels Theromyzon tessulatum can anticoagulant Therostatin be won. It prevents the blood from clotting by inhibiting blood clotting factor Xa , the activated form of thrombokinase . Therostatin can also prevent cancerous sores from metastasizing . In addition, other come protease - inhibitors as Theromin , Therin and Tessulin in the saliva of Theromyzon tessulatum ago.
Initial description
The leech was completely described in Latin by Otto Friedrich Müller in his work Vermium terrestrium et fluviatilium , published in 1774 on page 45 in the “Helminthica” section. Müller called him Hirudo tessulata , but the genus Hirudo was later divided into numerous genera.
supporting documents
literature
- Herbert W. Ludwig: Animals and plants of our waters . BLV Verlagsgesellschaft, Munich 2003, p. 142, ISBN 3-405-16487-7
- Hermann Hotz: Protoclepsis tesselata (OV Müller). A contribution to the knowledge of the construction and way of life of the Hirudineen Letterpress A. Kundig, Geneva 1938.
Individual evidence
- ↑ Helen Mellanby: Animal Life in Fresh Water: A Guide to Fresh-Water Invertebrates. Methuen & Co, London 1963, pp. 24-25. 978-94-009-5849-4
- ↑ James H. Thorp, Alan P. Covich: Ecology and Classification of North American Freshwater Invertebrates. Academic Press, London 2001. pp. 481-488. ISBN 978-0-12-690647-9
- ↑ Mark E. Siddall, Rebecca B. Rudinoff & Elizabeth Borda: Phylogenetic evaluation of systematics and biogeography of the leech family Glossiphoniidae. Invertebrate Systematics, 19, pp. 105-112, 2005, p. 105
- ^ Theromyzon tessulatum , page 45 in OV Müller: Vermium terrestrium et fluviatilium, seu animalium infusoriorum, helminthicorum, et testaceorum, non marinorum, succincta historia. Volume alterum. - pp. I-XXXVI [= 1-36], 1-214, [1-10]. Heineck & Faber, Havniæ & Lipsiæ, 1774
Web links
- Theromyzon tessulatum at Fauna Europaea