Dung beetles

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Dung beetles
Wood dung beetle (Anoplotrupes stercorosus)

Wood dung beetle ( Anoplotrupes stercorosus )

Systematics
Class : Insects (Insecta)
Order : Beetle (Coleoptera)
Subordination : Polyphaga
Partial order : Scarabaeiformia
Superfamily : Scarabaeoidea
Family : Dung beetles
Scientific name
Geotrupidae
Latreille , 1802
Geotrupes egeriei

The dung beetles (Geotrupidae) are a family of beetles within the superfamily Scarabaeoidea . They used to be counted as a subfamily of the scarab beetle family (Scarabaeidae). Until recently, the current family Bolboceratidae was also assigned to it as a subfamily. Browne & Scholtz raised this to family status in 1995. The animals live in forests, on fields and in the steppe. A little more than 150 species are known, 59 of them in Europe and 11 in five genera in Central Europe .

features

Beetle

The beetles are 10 to 45 millimeters long. They are dark brown, purple or black in color, often with a metallic sheen. The head is not curved down. The compound eyes of the Geotrupinae are complete, otherwise partially separated by a canthus , the ommatidia are fully developed (eucon). The epipharynx is rounded and in the Lethrinae has a notched front margin; with the other subfamilies it is right now. The antennae are 11- membered in the Geotrupinae and Lethrinae, 10-membered in the Taurocerastinae and carry a three-membered club. The mandibles of the Taurocerastinae and the Geotrupinae are elongated, double-serrated at the tip and have a brush and connection mesal . In the Lethrinae they differ between the males and females; the former are larger. They are also heavily sclerotized. Molar surfaces and the brush are asymmetrically serrated. The maxillary palps are four-limbed, the labial palps usually too, but the Lethrinae have three limbs. In the Lethrinae, the maxilla is heavily modified. An empodium is trained. The dorsodistale ridge of the wing vein 2Ax has a long and curved apex and a conspicuously long anterior area. The cross artery ScA-BR of 1BP is established. The spiracles on the first through eighth abdomen are functional. In the Geotrupinae and Lethrinae , the stigma of the first abdominal segment is located on the sternite , the stigma II to VII in the pleural membrane, in the genus Geotrupes the stigma of the eighth abdominal segment is located on the tergite , otherwise also in the pleural membrane. In the Taurocerastinae, the stigma of the first to the seventh abdominal segment is in the pleural membrane, that of the eighth on the tergite. Only in the Geotrupinae is a central nervous system known in which the ganglia of the meso- and metathorax are partially connected and all ganglia of the abdomen are connected to the metathorax.

Larvae

The body of the larvae is broadly C-shaped. The segments of the thorax and the first through sixth segments of the abdomen are divided dorsally into two folds. The cranium is symmetrical. Point eyes ( Ocelli ) are missing. With the exception of the genera Taurocerastes and Frickius , a frontoclypeal suture is not formed. The front plate ( clypeus ) is symmetrical or asymmetrical. The labrum is triple lobed. The antennae are tripartite and do not have a large sensory mark. The mandibles are asymmetrical, have a ventral process, and the ventral stridulation area is absent . Galea and Lacinia are clearly separated from each other. An organ for generating noise is formed on the thigh ring ( trochanter ) of the middle legs and the rear legs. The hind legs are significantly shortened in some species. The stigmas are sieve-like (cribriform).

Way of life

Entrance to the breeding chamber of a bull beetle next to sheep dung

The adults are diurnal and nocturnal and clumsy in flight. One can observe brood care in them : males and females dig underground passages or a brood chamber and store food supplies for their larvae there. The Geotrupinae feed on manure to mushrooms and humus. The Lethrinae are the only subfamily that gathers and macerates fresh leaves . The Taurocerastinae feed on the dung of herbivorous mammals.

In the case of the Lethrinae, it has been proven that the animals orientate themselves on the way from their breeding chamber to the food source, among other things by starlight. A 2013 study on this orientation method was awarded an Ig Nobel Prize. In 2016 it was published that dung beetles memorize a snapshot of the night sky with its light sources while they dance around the vertical axis on the dung ball.

Taxonomy and systematics

The family is divided into three subfamilies. The monophyly of the family is well founded by the following autapomorphies : In the adults , the mesal mandibular brush is large, the prementum is separated from the mentum , the dorsodistal branch of the wing vein 2Ax has a long and curved apex and a noticeably long anterior area, the transverse artery ScA- BR of 1BP is developed and the karyotype is 2n = 22 and not 20. In addition, one can observe brood care in the adult beetles . The monophyly of the subfamilies is also well founded.

The following overview lists all subfamilies as well as some Central European species:

Individual evidence

  1. ↑ Bolboceratidae. Tree of Life web project, accessed August 9, 2012 .
  2. ↑ a b Jiři Zahradnik, Irmgard Jung, Dieter Jung et al .: Beetles of Central and Northwestern Europe: an identification book for biologists and nature lovers . Parey, Berlin 1985, ISBN 3-490-27118-1 , pp. 143 f .
  3. ↑ a b c d e f Rolf G. Beutel, Richard AB Leschen: Handbuch der Zoologie - Coleoptera, Beetles, Volume 1: Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim) . 1st edition. de Gruyter , 2005, ISBN 3-11-017130-9 , p. 377 f . (English).
  4. ↑ Geotrupidae. Fauna Europaea, accessed August 9, 2012 .
  5. ^ Karl Wilhelm Harde , František Severa : Der Kosmos-Käferführer. The Central European beetle . Franckh-Kosmos, Stuttgart 2000, ISBN 3-440-06959-1 , p. 246 f .
  6. ↑ http://science.orf.at/stories/2773942/ How dung beetles find their way, science.orf.at, May 12, 2016, accessed May 12, 2016.
  7. ^ Vasily V. Grebennikov & Clarke H. Scholtz (2004): The basal phylogeny of Scarabaeoidea (Insecta: Coleoptera) inferred from larval morphology. Invertebrate Systematics 18: 321-34.
  8. ↑ David Kral & Oliver Hillert (2013): Three new Lethrus species close to L. raymondi (Coleoptera: Geotrupidae) from the Balkan Peninsula. Acta Entomologica Musei Nationalis Pragae 53 (1): 219-244.

Web links

Commons : Dung Beetles  - Collection of images, videos and audio files
Wiktionary: Dung beetles  - explanations of meanings, word origins, synonyms, translations