Colydium elongatum
| Colydium elongatum | ||||||||||||
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Colydium elongatum |
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| Scientific name | ||||||||||||
| Colydium elongatum | ||||||||||||
| ( Fabricius , 1787) |
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| Fig. 1: Top view | Fig. 2: underside |
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| Fig. 3: side view | Fig. 4: Head from the front |
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| Fig. 5: Larva | Fig. 6: Doll |
 A: upper jaw B: lower jaw C: lower lip |
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| Fig. 7: Mouth parts | Fig. 8: Sensor |
Colydium elongatum is a beetle from the family Zopheridae and the subfamily Colydiinae , which was previously considered an independent family andbelongsto the family of black beetles . The genus Colydium is mainly found in the New World ; in Europe, apart from Colydium elongatum, it is only represented by the species Colydium filiforme . However, the two types only differ in degree.
The species name elongatum ( lat. Extended) alludes to the unusual rod-like body shape, which is also present in Colydium filiforme . The generic name Colydium (from ancient Greek κώλον "kólon" for "limb" and ιδέα "idéa" for "shape") also stands for a beetle with an elongated body. In Reitter the genus is called thread beetles in German , in the Red Lists the name elongated thread sap beetle is given in two different spellings, and the name extended bark beetle can be found on the Internet , but these names are not common.
The hidden beetle is listed in the Red List of Endangered Species in Germany under category 3 (endangered).
Characteristics of the beetle
The narrow cylindrical beetle is almost five times as long as it is wide and becomes five to seven millimeters long. It is black-brown, legs and antennae are more red-brown in color.
The head (Fig. 4) is roughly the same length as it is wide and slightly trapezoidal. The round eyes are slightly arched and lie on the head side. The upper lip is not visible from above, its front edge is slightly double-indented. The curved upper jaws (Fig. 7 A) are unevenly bidentate at the tip, have a free skin flap on the inner edge and a cross-grooved grinding surface at the root. The terminal phalanx is large and slightly ax-shaped (Fig. 7 B). The end link of the lip switch (Fig. 7 C) is elongated ovoid and truncated at the tip. The eleven-part antennae (Fig. 8) are turned in under the side edge of the forehead in front of the eyes. They end in a tripartite club. This is more than twice as wide as the middle antennae of the antennae whip, the middle club segment is well twice as wide as it is long, and the base segment is significantly wider than it is long. In Colydium filiforme the limbs of the flagellum are less slender and the middle limb limb less transverse.
The almost rectangular pronotum is deeply grooved over the entire length in the middle of both species of the genus, parallel to it run near the side on one side, sharply delimited shallow furrows. In Colydium elongatum the pronotum is one and a half times as long as it is wide, in Colydium filiforme it is somewhat slimmer. The pronotum narrows very slightly towards the back and is still slightly wider than the head at the base. In Colydium filiforme , the base of the pronotum is not wider than the head. The pronotum is less densely punctured than the head, the points are elongated.
The elytra are ribbed lengthways. Rows of dots run between the ribs, which in Colydium elongatum consist of somewhat coarser dots than in Colydium filiforme . At the rear, the elytra are rounded together approximately in a semicircle. The elytra are uniformly only slightly lighter than the head and breast shield, the shoulders are only exceptionally a little lighter brown, while in Colydium filiforme the entire anterior part of the elytra are usually as brown as the legs.
The tarsi are all four-limbed, the limbs unlapped. The front, middle and rear hips are clearly separated (Fig. 2).
larva
The larvae (Fig. 5) are elongated and almost white. The limbs of the chest that support the legs are hardly wider and more sclerotic than the abdominal segments. The last two abdominal segments, especially the last, are more heavily sclerotized and yellow-brown on top. On the body there are two short chitinous appendages curved backwards and upwards in the shape of a horn.
biology
The species lives in and under rotten bark and in rotting wood of various deciduous and coniferous trees ( oak, beech, hornbeam , fir, spruce , pine , larch ). The adults can also be found on the wood at night, in exceptional cases also during the day. In Poland they appear from May to early August. The wintering takes place presumably as an imago.
The adults and probably also the larvae are predatory, mainly from larvae of various species of bark beetle . The larvae may also eat mushrooms that grow in the beetle tunnels. In England the species was often found together with the heartwood beetle Platypus cylindrus , the increasing spread of which is followed by Colydium elongatum . In addition to types of heartwood beetles, various bark beetles (Scolytidae) also belong to the range of prey for Colydium elongatum , but presumably no rodent beetles . The findings suggest that Colydium elongatum follows species that attack dying wood or fresh dead wood. With old dead wood these species are rarer and also finds of Colydium elongatum . The species can only be found preferentially in places without bark (trunk mirror) if the prey also concentrate on these dying areas of still living trees.
distribution
The range of Colydium elongatum includes that of Colydium filiforme , and reaches most of the European countries. There are no reports from Portugal , Ireland , the Baltic states with the Kaliningrad region , Moldova , central Russia , Albania and Macedonia . There are new finds from the Netherlands and Norway . Outside of Europe, the distribution area continues to the Middle East and West-North Africa.
In Germany, the species is more common in the east, it becomes significantly less common in the south and west. However, the frequency seems to be increasing recently not only in western Germany but also in western Europe (new finds in the Netherlands and the Rhineland ; spread in Great Britain).
literature
- Edmund Reitter : Fauna Germanica, the beetles of the German Empire III. Volume, KGLutz 'publishing house, Stuttgart 1911
- Heinz joy, Karl Wilhelm Harde, Gustav Adolf Lohse (ed.): The beetles of Central Europe . tape 7 . Clavicornia. Spektrum Akademischer Verlag, Munich 1967, ISBN 3-8274-0681-1 .
- Klaus Koch : The Beetles of Central Europe Ecology . 1st edition. tape 2 . Goecke & Evers, Krefeld 1989, ISBN 3-87263-040-7 .
- Gustav Jäger (Ed.): CG Calwer’s Käferbuch . K. Thienemanns, Stuttgart 1876, 3rd edition
Individual evidence
- ↑ a b c d Edmund Reitter : Fauna Germanica, the beetles of the German Empire III. Volume, KGLutz 'publishing house, Stuttgart 1911
- ↑ a b Colydium elongatum in Fauna Europaea. Retrieved November 5, 2012
- ^ Colydium in Fauna Europaea. Retrieved November 5, 2012
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (species)
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (genus)
- ↑ a b Red lists at BioNetworX
- ↑ Name "Outstretched Bark Beetle"
- ^ Polish entomological site
- ^ A b Klaas Reissmann: Colydium elongatum Fabricius 1787, Neufund for North Rhine (Insecta, Coleoptera, Colydiidae) Coleo 2, 2001 pp. 23-33
- ^ Klaas Reissmann : Colydium elongatum FABRICIUS 1787, other finds from North Rhine Coleo 3, 2003 pp. 67–70
- ^ O. Vorst: Colydium elongatum new to the fauna of the Netherlands (Coleoptera: Colydiidae) Entomological Reports 1994 Vol. 54 No. 2 pp. 23-25 ISSN 0013-8827
- ^ Arvid Pasche, Karl Erik Zachariassen: Colydium elongatum Fabr. (Col., Colydiidae) new to Norway Norwegian Journal of Entomology Vol. 23 No. 2 1976. as PDF
