Variable rodent beetle
| Variable rodent beetle | ||||||||||||
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Variable rodent beetle Grynobius planus |
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| Grynobius planus | ||||||||||||
| ( Fabricius , 1787) |
The variable rodent beetle ( Grynobius planus ) is a beetle from the family of rodent beetles . It is the only representative of the genus Grynobius and is widespread in Europe.
In the Red List of Endangered Animals, Plants and Fungi in Germany , the species is listed under category 3 (endangered).
Notes on names and synonyms
The species was first described in 1787 by Fabricius under the name Anobium planum . The short description begins with the sentence: Anobium fuscum thorace plano ( Latin: a dark anobium with a flat chest section). This explains the species name planus (Latin for flat). The genus Anōbium (from ancient Greek άνευ "áneu" for "without" and βίος "bíos" for "life" because the animals play dead) has been split up several times.
As the name of the variable rodent beetle suggests, the beetle varies in appearance. It has therefore been described under different names. The Fauna Europaea has seven synonyms . Mulsant described Anobium planum in 1864 (Fabricius 1787) in great detail and placed the beetle as the third species in the genus Priobium established by Motschulsky in 1845 and split off from Anobium . Directly before that, Mulsant presented the species Anobium tricolor (Olivier 1790) , which was also described in detail . Mulsant himself points out the astonishing similarity between the two species. Because of the existence of intermediate forms, the differences are now explained by the variance within a species and the names ( Anobium ) tricolor and ( Anobium ) planum are considered synonyms.
The genus Grynobius was established in 1859 by the Swede Thomson in the form of an identification key for the anobiids with nine genera. The key does not contain any indication of the meaning of the generic name. According to Schenkling , he is from old Gr. γρυνός “grynós” for “dry wood” and βίος “bíos” for “life” and indicates that the beetle develops in dry wood.
Thomson named Anobium castaneum ( Fabricius ) as a type for the genus Grynobius . He took over the name Mulsant used in the above-mentioned script for the beetle, which he cited in the first place of the three species of Priobium and whose description also points to extensive agreement with tricolor and planum . However, Fabricius did not describe Anobium castaneum , but quoted Anobium castaneum Olivier . However, the Anobium castaneum described by Mulsant is not identical with Anobium castaneum (Olivier), but with Anobium excavatum ( Kugelann , 1791), which Mulsant also uses as a synonym . For this reason, Anobium excavatum (Kugelann, 1791) was designated as the type for the genus Grynobius in 1976 by the International Commission for Zoological Nomenclature . Today Grynobius excavatus is counted as belonging to the same species as Grynobius planus , so the names are considered synonyms. The specific epithet excavatus is explained from the Latin short description by Kugelann: Ferrugineum, thorace subaequali, antice excavato, ... In the German description Kugelann explains : Very similar to the previous one in size and shape, but it differs in its smaller, more round shape and breast shield cut out in front (lat. excavatus = cut out). In Reitter there is a fourth variant classified as a species: Priobium Eichhoffi . The beetle was named by Seidlitz in 1889 after the forester and coleopterologist Eichhoff . Also Grynobius eichhoffi (i) is a synonym for today Grynobius planus considered.
Description of the beetle
The four to six millimeter long beetle is matt dark brown, the wing covers can be lighter, which, together with rust-colored legs and antennae, results in a tricolor (name tricolor). The top is very fine, short, dense and yellowish hairy lying down. The puncture on the top is dense and wrinkled.
The head is tilted downwards. It is smaller in the female than in the male. The eleven-limbed antennae have a roughly dotted first limb, followed by a spherical to egg-shaped second limb and a thinner third limb that is slightly to significantly longer than the following limb. The fourth to the eighth antennae widens conically and is hardly longer than wide. The antennae end with three very elongated links. In the male these are together as long as the seven preceding limbs are together. The terminal of the antennae in the male is almost straight on the inside and ends at an obtuse angle. In the female, the three terminal links together are no longer than the six preceding ones together. The end link is elongated, elliptical and pointed. The antennae are pivoted away from each other between the eyes , their distance is three times as large as the transverse diameter of the eyes visible from above. The eyes are large and protrude like a hemisphere. The upper lip is punctured very finely to negligibly and covered with fine hair on the front edge. The upper jaws are flat with a shiny and smooth tip.
The pronotum is hardly wider than it is long, in the male it is as long as it is wide. In addition, the pronotum is slightly more rounded in the females than in the males. In both sexes, it is significantly narrower than the elytra and slightly to significantly wider than the head. In front, the pronotum is obliquely truncated to slightly hooded. However, it is flat and not raised like a comb like some related species (name planus ). Behind the front end it is more or less constricted (name excavatus ). The pronotum sides are not canted, the pronotum base is clearly edged and slightly double-indented (slightly indented in front of each wing cover). A longitudinal groove in the pronotum is only indicated.
The label can be a little wider than long to a little longer than wide. It is rounded at the tip, strongly and often lighter haired and protrudes above the level of the surrounding parts of the elytra.
The elytra are three and a half to four times as long as the pronotum. Their sides are approximately parallel. In cross-section, the elytra are less arched than those of related species. The elytra have eleven deep and clear stripes made of slightly elongated square points, these point stripes are about the same width or significantly narrower than their spaces. The innermost point stripe is inclined and reaches only about a sixth of the length of the wing cover, the others narrow a little at the end of the wing cover and converge. The dotted stripes curve slightly outwards at the front. The spaces in between are slightly to distinctly curved. The first space communicates with the outer space at the wing cover end. This connection forms a raised, thick bead. The elytra in the female rather individually rounded, in the male rather individually truncated.
The underside of the insect is only slightly arched and wrinkled and weakly punctured, the puncture is stronger on the sides of the breast. There are no recesses to insert the legs. The two anterior segments of the abdomen are only moderately elongated, the first abdominal sternite ends with two bays, the second is not much longer than the third. The mid-thoracic process that separates the mid-hip varies in width from slightly wider than to two and a half times as wide as the fore-chest process that separates the front hips. The rear hips are very widely separated from each other. The rear breast has a clear longitudinal furrow that extends over the last two thirds of the male and the rear half of the female. The legs are strong. The five-limbed tarsi are shorter than the splints, the hind tarsi best developed. The claws on the end link of the tarsi are small, membranous expanded and silky hand tomentiert .
larva
Like the larvae of related species, the larvae of the variable rodent beetle have a protruding, small and arched head with downward-pointing mouthparts. The three breast segments are not significantly larger than the ten abdominal segments. There is only one ocelle on each side of the head . The antennae are very short, the basal phalanx has a button attached. The upper jaws are simply pointed. The grinding surface of the lower lip is bilobed, the inner lobe is much narrower than the outer. The claws are only slightly curved. They are about half the length of the rail. There is no lobe at its base . A key in English for the Grynobius larva can be found on the Internet.
biology
The beetle develops in dried branches of various hardwood species (often in the rose family mountain ash , hawthorn , crab apple , also in oak , beech , chestnut , poplar , ivy , in growths on the trunks of the hornbeam , often also in hazel , in Northern Europe also in stored wood of birch , alder and willow ) in sun-exposed locations in deciduous forests, also in solitary trees. Infested trees can remain colonized for many years and the larvae can then also be found in the trunk or in stumps . Development takes at least two years. Pupation takes place in autumn and the species overwinters as an imago . The beetles appear in late spring. The beetle is active in the evening and then walks around briskly. If shaken, it drops.
The species is threatened by the lack of dead wood .
distribution
The species occurs from southern northern Europe to southern Europe. It has been found in Western Europe and Western Central Europe. It is absent in the Alpine region and has been proven on the plains in Germany as far as Mecklenburg .
In the north, the occurrence is limited to the southwestern parts of Scandinavia . A clear preference for the oceanic climate is observed in western Norway . In the Iberian Peninsula , the species occurs mainly in the northern mountainous regions.
literature
- Heinz joy , Karl Wilhelm Harde , Gustav Adolf Lohse (ed.): The beetles of Central Europe . tape 8 . Teredilia Heteromera Lamellicornia . Elsevier, Spektrum, Akademischer Verlag, Munich 1969, ISBN 3-8274-0682-X . P. 38
- Klaus Koch : The Beetles of Central Europe Ecology . 1st edition. tape 2 . Goecke & Evers, Krefeld 1989, ISBN 3-87263-040-7 . P. 268
- Edmund Reitter : Fauna Germanica, the beetles of the German Empire III. Volume, KGLutz 'Verlag, Stuttgart 1911 p. 307 f as Priobium
Individual evidence
- ↑ a b c d e f Grynobius planus at Fauna Europaea. Retrieved December 22, 2014
- ↑ a b Grynobius at Fauna Europaea. Retrieved December 22, 2014
- ↑ a b Distribution map of Fauna Europaea Distribution of the species in Europe ( Memento of the original from January 15, 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.
- ↑ Red List of Endangered Animals in Germany ( Memento of the original from March 1, 2016 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.
- ↑ Joh. Chris. Fabricius: Mantissa insectorum Volume 1 Copenhagen (Hafnia) 1787 First description as the 4th species of the 15th genus
- ↑ a b Sigmund Schenkling: Explanation of the scientific beetle names (genus) in detail in the 2nd edition 1922 .
- ↑ a b Synonyms in NBN
- ↑ a b Mulsant, Histoire naturelle des coléoptères de France t.19, 1864 key for the species p. 52 and description for tricolor and planum p. 55ff
- ↑ WF Erichson u. a .: Natural history of the insects of Germany Coleoptera 5th volume, 1st half Berlin 1898 Comment on Pr.tricolor p. 97
- ^ A b Carl Gustav Thomson: Scandinavia Coleoptera 1st vol. Lund 1859 S. Preview in the Google book search
- ↑ Joh. Chris. Fabricius: Entomologiae systematicae, emmendatae et auctae Volume 1 Part 1, Copenhagen (Hafnia) 1792 p. 238
- ^ Request to change the type of the genus Grynobius
- ↑ Decision of the ICZN on the type for the genus Grynobius
- ^ Johann Gottlieb Kugelann: List of the beetle species discovered in some areas of Prussia ... in G. H. Schneider (Hrsg.): Latest magazine for lovers of entomology 1st volume, 4th issue p. 488, Stralsund 1792 preview in the Google book search
- ↑ Georg Seidlitz: Fauna baltica - The beetles of the German Baltic Sea provinces of Russia, 2nd edition, 1891, p. 498
- ^ Coleo-net, genus Grynobius
- ↑ Coleo-net, family Anobiidae
- ↑ Adam G. Böving: The Larva of Nevermannia dorcatomoides Fischer with comments of the classification of the Anobiidae according to their larvae (Coleoptera, Anobiidae) in Proceedings of the Entomological Society of Washington Vol. 29, No. 3, March 1927 p. 51 ff key p. 57
- ^ Information sheet of Polish coleopterologists
- ↑ Norwegian Species Journal
- ↑ a b Frank Baum: Beetles and beetle fauna on the Belchen in the Black Forest 3rd page of section 3.1
- ↑ José Ignacio López-Colón: Algunos datos corológicos sobre Anóbios Ibéricos (Coloeptera, Anobiidae) in Bol. SEA, nº 28 (2001): 115-116 (Spanish)
