Common Rottenwood Weevil
| Common Rottenwood Weevil | ||||||||||||
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Common Rottenwood Weevil |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Cossonus linearis | ||||||||||||
| ( Fabricius , 1775) |
The common weevil ( Cossonus linearis ) is a beetle from the family of weevils . It also bears the German name Schlanker Faulholzrüssler ; Flat weevil or slender bark weevil .
The beetle is not protected in Germany, but is on the warning list in Schleswig-Holstein as potentially endangered .
Notes on the name
The species was first described by Fabricius in 1775 under the name Curculio linearis . The description contains the characterization: Elytra striata ( Latin for striated wing coverts). This explains the species name linearis (Latin with lines). Later the genus Curculio was split up several times and the rotten weevil was placed in the genus Cossonus . The genus name Cossonus is from Altgr. κόσσος kóssos derived for woodworm. It expresses that the beetle can be found under wood bark. The endings -rüssler of the German names indicate that it originally belonged to Curculio . The other parts of the German name express that the beetle is found under the bark of rotting wood, that the beetle is flat and its trunk is flattened. As the word "mean" in the name shows, the four to six millimeter long beetle is common, at least in places.
The genus Cossonus is only represented by three species, all of which also occur in Europe and which are assigned to two different subgenera. A fourth species is now assigned to the genus Brachytemnus .
Description of the beetle
The body is elongated and very flat (Fig. 2). It is hairless and shiny dark. The elytra are dark brown, antennae and legs are rusty red.
The narrow head is extended into a trunk. The oval eyes sit at the base of the trunk and are not bulging laterally.
The trunk is stretched forward even at rest and cannot be inserted into a groove in the front chest. It is widened like a shovel in front of the deflection point of the sensor. The narrow basal part of the trunk is slightly longer than the enlarged part at the top. The shape of the proboscis does not differ significantly in males and females.
The feelers are turned behind the extension of the trunk. The sensor pits cannot be seen from above. They run obliquely back and down on the side of the trunk. They are short and end far before the eyes (Fig. 1). The first antenna segment forms a shaft that does not reach the eyes, the following seven flagella segments are bent forward and shaped like a string. The first two limbs of the scourge are elongated, the following short, wider than long, and tightly packed together. The end links form an egg-shaped club. The club members are only separated from each other by fine seams (weakly curled), so that in old descriptions the club was counted as just one antennae (the ninth).
The throat plate is viewed from the top approximately rectangular front and constricted to the width of the head. All four corners are rounded. The disk of the pronotum is finely dotted , the sides strong. However, the points are scattered. On both sides of the weak and only basally short central keel, the puncture is particularly strong and dense.
The elytra are only a little wider than the pronotum and strongly flattened above. They are brown and completely cover the abdomen. You have a shoulder bulge, the sides are parallel and at the back they are rounded together in a semicircle. They have distinctive stripes of dots. The spaces between the dot stripes are no wider than the dot stripes themselves. The label is clearly visible.
The first two abdominal rings are fused together, the third and fourth abdominal rings are very short (Fig. 4).
The front hips are separated from each other at around two thirds of the hip diameter (Fig. 4), the distance between the front hips is smaller in the two other Central European species of the genus . All splints are drawn out distally on the outside in a strong, inwardly curved spur. The four-limbed tarsi are short and narrow, the claw limb only slightly shorter than the rest of the limbs combined. The claws are not grown together at the base (free).
larva
As is typical of bark beetles and weevils, the larva is white, legless and curved towards the abdomen. It has twelve body segments. Only the rounded head with the mouthparts pointing downwards is more heavily sclerotized . The antennae are extremely small, as papillae covered with a short purse. The head shield and upper lip are leathery and cover the gap between the upper jaws (mandibles) from above. The mandibles are strongly developed, the maxillae have a ciliate ark with short, conical buttons. Two short, cone-shaped, two-part lip buttons are formed. The legs are missing, but are indicated by a rounded foot hump, which is equipped with a stiff bristle. One stigma is located on each side of the back bulges of the first eight abdominal segments, a ninth pair of stigmas on the side of the back bulge of the prothorax.
biology
The adult animals fly to suitable habitats. They are used as carriers for various phoretic mites .
The species is hygrophilous and is mainly found on banks, floodplains and in forests. It is not restricted to one host plant, but the larva is found in various hardwoods, but almost exclusively in willow and poplar species. She is counted to the guild of the reclaimed wood settlers. On the trees, the larva feeds under the bark (corticol) or inside, on dying or dead parts (xylodetricol). They are found preferentially in white rotten wood, which is still comparatively hard but already fungal.
Occurrence and distribution
You can find the beetle all year round, but more often in May and June. Its occurrence is limited to Europe, towards the north the species is rarer, but it is not consistently widespread in southern Europe either. For example, it is absent in Great Britain , but also in Greece .
literature
- Heinz joy , Karl Wilhelm Harde , Gustav Adolf Lohse (ed.): The beetles of Central Europe . tape 11 . Rhynchophora (end). Goecke & Evers, Krefeld 1983, ISBN 3-87263-031-8 .
- Edm.Reitter: Fauna Germanica, the beetles of the German Empire. Volume 5, KGLutz 'Verlag, Stuttgart 1912.
- Gustav Jäger (editor): CG Calwer 's Käferbuch. K. Thienemanns, Stuttgart 1876, 3rd edition
- Handbook of Zoology. Arthropods, arr. by A. Gerstaecker, Leipzig Verlag Wilhelm Engelmann, 1863.
- Klaus Koch : The Beetles of Central Europe . Ed .: Heinz Freude . tape 3 : ecology . Goecke & Evers, Krefeld 1992, ISBN 3-87263-042-3 , pp. 254 .
Web links
Individual evidence
- ↑ a b Distribution, systematics and synonyms for Cossonus linearis
- ↑ Red lists at BioNetworkX
- ↑ JCFabricius: Species insectorvm exhibentes eorvm differentias specificas, synonyma avctorvm, loca natalia, metamorphosin adiectis observationibvs, descriptionibvs, Bd.I Hamburg, Kiel 1781 first description p. 247, no. 10
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (species)
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (genus)
- ^ Cossonus at Fauna Europaea. Retrieved March 11, 2013
- ↑ Cossonus Cossonus (subgenus) in Fauna Europaea. Retrieved March 11, 2013
- ↑ Cosonus Caenocossonus (subgenus) in Fauna Europaea. Retrieved March 11, 2013
- ↑ Species of the genus Byctiscus at BioLib
- ^ WF Erichson: "On the systematic knowledge of the insect larvae" Archive for Natural History, 8th year, 1st volume, Berlin 1842
- ↑ Alois Kofler & Karl Schmölzer: "On the knowledge of phoretic mites and their carriers in Austria" Ber.nat.-med.Verein Innsbruck, Volume 87, pp. 133–157, Innsbruck, Oct. 2000 as PDF
- ↑ Schmidl.J & Bussler.H 2004: Ökologische Gilden xylobionter Käfer Deutschlands.-Naturschutz und Landschaftsplanung 36 (7); Stuttgart as XLS, no. 1402 ( Memento of the original from December 27, 2015 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.
- ↑ Mareike Güth: "Landscape ecological aspects of the settlement of agriculturally used open land locations" Diploma thesis Friedrich Schiller University Jena Institute for Ecology Jena 2000 as PDF ( Memento of the original from February 23, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Georg Möller: Structure and substrate binding of wood-dwelling insects, focus on Coleoptera - Beetle Dissertation, Institute for Zoology at the Free University of Berlin, March 2009 as PDF
