Crayfish
| Crayfish | ||||||||||||
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A crab infested by Sacculina with the typical sack-like outgrowth Ernst Haeckel 's Kunstformen der Natur , 1904. |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Sacculina | ||||||||||||
| Thompson , 1836 |
The crayfish ( Sacculina ) are parasites from the subclass of barnacles . Crabs (brachyura) serve as hosts ; The food is supplied via a root-like network that the parasite forms inside the host animal, while the reproductive organs grow in a sac-like protuberance on the underside of the host.
Life and behavior
The adult animals show no similarity with other more barnacles as barnacles or barnacles , but can this order be assigned clearly about their larval stages.
The female larva of the Sacculina ( Cypris ) looks for a crab and tries to nestle in a hollow at the bristle base of the crab shell. It then sheds its skin into cypris pupa and penetrates the host with the cannula-like arrow of the Kentrogon . The female sacculina larva grows inside the crab ( internals ) and at the same time forms a sac-like protuberance on the outside of the host ( externa ) - typically at the point of the rear thorax where the crab hatches its eggs. The topical comprises as breeding bag the reproductive system of the animal, the internals first forms a nucleus and grow into a network of roots which umspinnt the surface of the intestine, midgut gland, muscle, and gonads of the host; it is the absorption system. Both parts are connected via a stem-shaped section.
When a female sacculina larva attacks a male crab, it actively changes its hormonal balance and tries to "polarize" the male crab to a female specimen. First the male crab is sterilized, later the abdomen changes. It was observed that male crabs infested with sacculina mimicked the courtship rituals of female crabs.
After the Sacculina infestation , the crab loses the opportunity to molt and grow with it. Due to the feeding and growth of the sacculina larva, the crab also loses the ability to rebuild its large claws, which are mainly used for defense.
Reproduction
The cypris larva of the male Sacculina crab looks for infested crabs in order to fertilize the eggs of the female parasite on the underside of the crab. The crab then changes its behavior again. She guards and cares for the eggs as if they were her own.
species
- Sacculina americana Reinhard, 1955
- Sacculina atlantica Anderson
- Sacculina bicuspidata Boschma, 1931
- Sacculina boschmai Reinhard, 1955
- Sacculina bourdoni Boschma, 1960
- Sacculina carcini Thompson, 1836
- Sacculina gerbei Bonnier, 1887
- Sacculina gibbsi Hesse
- Sacculina gonoplaxae Guerin-ganivet, 1911
- Sacculina hirsuta Boschma, 1925
- Sacculina inflata Leuckart, 1859
- Sacculina pustulata Boschma, 1925
- Sacculina rathbunae Boschma, 1933
- Sacculina reniformis Boschma, 1933
- Sacculina schmitti Boschma, 1933
- Sacculina tesselata Boschma, 1925
Web links
Individual evidence
- ↑ Rolf Siewing (Ed.): Textbook of Zoology, Volume 2 - Systematics, Chapter Crustacea / Copepodoidea. Gustav Fischer Verlag, 1985, ISBN 3-437-20299-5