Craesus
| Craesus | ||||||||||||
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Larvae of Craesus septentrionalis |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Craesus | ||||||||||||
| Leach , 1817 |
The genus Craesus ( Syn .: Croesus ) belongs to the plant wasps (Symphyta) within the hymenoptera (Hymenoptera). There are four types in Europe.
features
The animals are 7 to 11 millimeters long, depending on the species. Typical of the genus Craesus are the specially shaped hind legs, the first tarsal link of which is noticeably widened like a leaf.
The larvae ( anal caterpillars ) look, like those of all plant wasps, very similar to the caterpillars of butterflies , but differ from them by a total of eight instead of a maximum of seven pairs of legs. They have a black head, the rest of the body is yellow-green, green or blackish in color.
Way of life
The adults reproduce predominantly parthenogenetically. Often there are two generations a year. The larvae feed on birch trees such as alder , birch , hazelnut and hornbeam . They mainly sit in groups on the edge of the leaf and feed from the outside in. When disturbed, they curve the body characteristically to an "S" and thus present the ventral glands characteristic of the subfamily Nematinae, which in C. alniastri and C. septentrionalis contain exclusively dolichodial . The pupation of the animals takes place in the earth.
European species
- Craesus alniastri (Scharfenberg, 1805) (= Craesus varus (Villaret, 1832))
- Craesus brischkei (Zaddach, 1876)
- Craesus latipes (Villaret, 1832)
- Craesus septentrionalis (Linnaeus, 1758)
credentials
- ^ A. Taeger, E. Altenhofer, SM Blank, E. Jansen, M. Kraus, H. Pschorn-Walcher, C. Ritzau: Comments on the biology, distribution and endangerment of the plant wasps in Germany (Hymenoptera, Symphyta). ( Memento of the original from June 16, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: A. Taeger, SM Blank: Plant wasps in Germany. Goecke & Everts, Keltern 1998, pp. 49-135.
- ↑ JL Boevé, JC Braekman, D. Daloze, M. Houart, JM Pasteels: Defensive secretions of Nematinae larvae (Symphyta - Tenthredinidae). In: Cellular and Molecular Life Sciences (CMLS). 40 (6), 1984, pp. 546-547.
Web links
- Croesus (Leach) ( Memento from August 28, 2008 in the Internet Archive )