Cross click beetle
| Cross click beetle | ||||||||||||
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Snapback beetle ( Selatosomus cruciatus ) stuck |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Selatosomus cruciatus | ||||||||||||
| ( Linnaeus , 1758) |
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| Image 4: View from above, below, front and the side | |||||||
The cross-beetle ( Selatosomus cruciatus ) is a beetle from the family of beetles and the subfamily of Ctenicerinae. The black cross on the wing covers and the bright color on the pronotum and the underside of the body make the beetle within the genus Selatosomus unmistakable. The beetle becomes ten to fourteen millimeters long.
The species is listed under category 3 (endangered) in the Red List of Endangered Species in Germany. In Rhineland-Palatinate , it is classified as seldom without a current risk . In North Rhine-Westphalia it is considered lost (not found for over fifty years).
Notes on the name
The species was first described by Linnaeus in 1758 under the scientific name Elater cruciatus . The short description contains the phrase: cruce nigra margineque nigro ( Latin , with black cross and black border). This explains the species name cruciātus (Latin crux, crúcis, cross, provided with a cross).
The genus Selatosomus was established by the Englishman Stephens in 1830. The generic name Selatosōmus (from ancient Greek σέλας, σέλατος sélas, sélatos, gloss and σώμα sōma, body) expresses that the body has a metallic sheen. Stephens writes: The typical species of this genus are eminently distinguished by the splendor and brilliancy of their coloring, the surface glabrous and richtly adorned with lively metallic hues ( en .: The typical species of this genus are outstanding because of their sheen and brilliance Coloring, the hairless surface decorated with vivid metallic tones is excellent).
The genus Selatosomus is represented in Europe with ten species in two subgenera. Selatosomus cruciatus belongs to the subgenus Pristilophus. There are over seventy species worldwide, which are divided into five subgenus.
Description of the beetle
In the cruciform beetle, a member of the subfamily Ctenicerinae, the forehead ridges , which arise from the antennae in front of the eyes, run diagonally forward, then towards the middle, where they end before they have reached the middle of the head (Fig. 1). The front chest is fused with the undersides of the pronotum (front chest pisterns) from the head to the front hip cavities. The fusion seam is not deepened to accommodate the antennae and is only set off inwards by a line (simple Prosternal seam , Fig. 3). Compared to the genus Ctenicera , which gives the subfamily its name, the end of the fore-chest towards the head (Prosternal lobe, Mentonnière) is more widened forward and downward and round, not truncated (Fig. 3, marked orange). It covers the mouthparts up to the upper jaw when the beetle lowers its head slightly. At the back, the front breast is pulled out into a long point (Fig. 3), which can snap into a corresponding pit in the middle breast and snap out again. This quick mechanism, typical of the family, enables the beetle to jump into the air from the supine position.
The legs are rusty red, sometimes a little darkened. The tarsi are all five-part. The claws are not serrated or serrated.
The rear hip, which connects to the rear of the rear chest, is hollowed out to partially accommodate the rear thighs. The part that is on the same level as the rear chest is called the thigh ceiling . The thigh covers in the cruciferous beetle narrow outwards so that the shiny side of the thigh cavities, which are at the level of the abdomen, is clearly visible in the top view (Fig. 2).
The top appears hairless to the naked eye. The black pronotum has an elongated red spot on both sides. The drawing on the wing covers in the form of a cross can be greatly reduced, so that only a shoulder mark and the seam where the wing covers meet remain black. Or the blackening is extensive, so that only two elongated red-yellow spots can be seen on each wing cover. There are also yellow-red vertical stripes on both sides of the black underside.
The head is small and significantly narrower than the pronotum: the mouthparts do not point downwards in the rest position, but forward (prognath). In contrast to other genera of the subfamily, the eleven-jointed antennae do not have long antennae (combed) in the males either. The second link is short, the third elongated, neither of which is enlarged. The following links are slightly widened (sawn) inwards, and shorter than the third, but their widening is not acute-angled on the outside. The fourth link is no longer than the third, but significantly longer than the fifth.
The pronotum is clearly bordered on the side, but not in front. It has long back angles that are keeled and, viewed from below, are broadly truncated at the end (Fig. 3).
Occurrence
The beetle is widespread in Central Europe , but its frequency decreases from northeast to southwest. Its distribution area extends there as far as the Pyrenees . In the east it is distributed across northern Europe to Siberia , it is also found in North America . It is absent in higher mountains.
The beetles live in beech forests, on moist sandy soils near the banks and on the edges of the forest . They can occur more frequently at the sites where they were found, but the species is rare to very rare in some areas. The adults can be found in May and June on bushes, on tree stumps and on lying wood.
Way of life
The larvae live in the soil and feed on the roots of herbaceous plants.
literature
- Heinz Joy, Karl Wilhelm Harde, Gustav Adolf Lohse: The beetles of Central Europe . tape 6 : Diversicornia . Spectrum, Heidelberg 1979, ISBN 3-87263-027-X .
- Klaus Koch : The Beetles of Central Europe Ecology . 1st edition. tape 2 . Goecke & Evers, Krefeld 1989, ISBN 3-87263-040-7 . P. 74
Individual evidence
- ↑ Red lists at BioNetworkX
- ↑ C.Linnaeus: Systema Naturae per Regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata Stockholm 1758 first description page 404 No. 6
- ↑ Sigmund Schenkling: Nomenclator coleopterologus 2nd edition Jena 1922 Explanation of the scientific beetle names (species) in short form
- ↑ Sigmund Schenkling: Nomenclator coleopterologus 2nd edition Jena 1922 Explanation of the scientific beetle names (genus) in short form
- ↑ James Francis Stephens: Illustrations of British Entomology… Mandibulata Vol. III, London 1830 Description of the genus Selatosomus Genus 227 p. 268
- ↑ Selatosomus in Fauna Europaea. Retrieved March 22, 2013
- ↑ Selatosomus (Pristilophus) cruciatus in Fauna Europaea
- ↑ Subgenera of the genus Selatosomus at BioLib
