Cerocoma schaefferi

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Cerocoma schaefferi
Cerocoma schaefferi, female

Cerocoma schaefferi , female

Systematics
Class : Insects (Insecta)
Order : Beetle (Coleoptera)
Subordination : Polyphaga
Family : Oil beetle (Meloidae)
Genre : Cerocoma
Type : Cerocoma schaefferi
Scientific name
Cerocoma schaefferi
( Linnaeus , 1758)
Cerocoma schaefferi MHNT Fronton Male Portrait.jpg
Fig. 1 Head and breast shield male (♂)
Cerocoma schaefferi female.jpg Cerocoma schaefferi front tarsus.jpg
Fig. 2 blue variant ♀
Cerocoma schaefferi male antenna.png
Fig. 3 Sensor ♂ Fig. 4 Anterior tarsi

Cerocoma schaefferi is a beetle from the family of blister beetles . The genus Cerocoma is represented in Europe with thirteen strongly similar species , which are divided into two subgenera. Worldwide the genus comprises 23 species in five subgenera. Cerocoma schaefferi is listed in the Red Lists of Germany and Bavaria under category 1 (critically endangered), in Schleswig-Holstein it is considered extinct or lost . In the Red Lists, the beetle bears the name Schäffers Breithorn oil beetle .

Notes on the name

The male beetles were already described in 1758 in the famous 10th edition of the Systema naturae by Linné under the name Meloe schaefferi as the 7th species of the 188th genus. Linnaeus compares the species with the Spanish fly and states that he got it from Germany from a Mr. Schäffer. This explains the species name schaefferi (named after Jacob Christian Schäffer ). Schäffer gave the male the German name Kronenkäfer, the female the name Keulenkäfer (Käulenkäfer) because of the different shape of the antennae . The genus Cerocoma was established by Geoffroy in 1762 . The generic name is from Altgr. κέρας "kéras" for "horn" and κόμη "kóme" for "head of hair" derived and refers to two long tufts of hair on the upper lip. Cerocoma schaefferi represents the type of the genus.

Description of the beetle

The beetle has a weakly sclerotized exoskeleton . It becomes seven to ten millimeters long in both sexes. It has a shiny metallic green, the females occasionally also have a metallic blue (Fig. 2). Only the antennae, mostly the mouthparts and the legs are pale lemon yellow, the thighs can be completely or partially green. The body is hairy white protruding. The sexes differ significantly in the construction of the sensor.

The head is lowered perpendicular to the body axis. Seen from above, it is wider than it is long. The upper lip is unusually elongated, somewhat heart-shaped and has two tufts of hair in front. The upper jaws are narrow with a membranous inside, triangularly elongated and not split at the tip. The jaw and lip probe are slim, the end link of the jaw probe is widened towards the end. In the male, the second and third segments of the jaw palpation are vesicularly enlarged. With him, the parts of the head skeleton are separated by sharp seams. The forehead does not have a red mark in either sex. The structure of the nine-segment antennae distinguishes the genus according to Geoffroy from all other beetle genera: they are both partially combed and end in a one-segment club. In the case of Cerocoma schaefferi , the last antenna segment in the male (Fig. 1 and 3) forms a smooth, irregularly egg-shaped, somewhat darkened club with no outgrowths or structures. The three penultimate links are small and have no attachments. The base limb, on the other hand, has a long lobed outgrowth, the second limb is small and spherical, the third is unusually large, heavily sculpted and twisted. In most related species, the terminal link of the antennae of the male is more complex. Overall, the antennae in the male is curved in an S-shape. In the female, the first through the eighth antennae are simple, the last ones are wider than they are long. The end link widens towards the end. It is hardly longer than wide and about as long as the three penultimate links combined. In both sexes, the antennae are nine-jointed and are deflected over the base of the upper jaw well in front of the eyes.

The pronotum is unrimmed and longer than it is wide. Especially in the male it is a bit rough. In the male, it also shows a sharply delimited, oblong, round, slightly oblique impression on the front side (Fig. 1). Like the elytra, it is finely dotted . The base of the pronotum is not red-yellow.

The flat elytra are collectively wider than the pronotum. The sides run approximately parallel to the jointly rounded end.

The underside is also green. The legs are long. The tarsi of the hind legs are four-limbed, the other tarsi consist of five limbs. The claw link is large, the very long and thin claws are split and imperforate on the inner edge. The front rails of the males are broadly flattened and keeled (Fig. 1), the keel is simply curved when viewed from the side. The limbs of the front legs are expanded (Fig. 4 left). In females, the anterior splint is cylindrical with a large pointed tooth at the outer end, the anterior splint is not enlarged (Fig. 4 right). The rear rails have two terminal spines in both sexes, the outer one of which is thick.

biology

The beetle can be found in places that are warm and dry, for example on warm and dry slopes, dry fields, ruderal areas, gravel pits or in heathland. It is mainly found on the flowers of tubular daisy family ( chamomiles , chrysanthemums , yarrow , ring thistles ) but also on various umbellifers and occasionally on flowering shrubs. In an old German textbook on insects, the beetles are referred to as quick fliers .

The beetles eat pollen , the larvae presumably live parasitically on larvae of wild bees .

In a comparative study of the cleaning and sexual behavior of different species of the Cerocoma genus , some clear differences between the species could be found. Males and females show a cleaning behavior that relates to different parts of the body. The antennae are cleaned individually with the front legs. The outside of the front legs is used to clean the inside of the probe. This can be done with a single stroke or rubbing with numerous quick movements back and forth. The jaw buttons are cleaned by pulling the front rails over the head and rubbing against the buttons. A single jaw button can be cleaned by slowly stroking the front rail along it several times. The head moves sideways. Or both buttons are cleaned at the same time by quick movements of both front rails, with the head moving forward. Often the cleaning of the buttons precedes the cleaning of the sensors. At Cerocoma schaefferi, cleaning the head capsule is a by-product of cleaning the buttons. The middle and rear pair of legs are used to clean the wing covers. A single leg or two legs on the same side move back and forth, with the front leg rubbing mainly the front half of the wing cover and the back leg primarily rubbing the back half of the wing cover. The rear legs are cleaned by the middle legs, the splints of the two front pairs of legs are cleaned with the mouthparts.

The pairing is preceded by extensive advertising. This can be broken down into three distinctly different phases. In the first phase, the male stands behind the female and touches the end of the female abdomen and its wing covers with the tips of the buttons. The antennas are not used. This palpation shifts progressively forward, whereby the male increasingly comes to stand over the back of the female. This phase only lasts about a second and is often omitted. In the second phase, the male rises on the back of the female. Now the male rubs the front part of the rail of the foreleg against the elytra and occasionally the pronotum of the female up and down while the body rocks back and forth. This behavior was observed in German and Italian populations, while in a Greek population the males tapped the females with their anterior tarsi. At the same time, the male touches the female with the tip of the jaw probe on the base of the wing cover. During this phase, the male genitals remain in the body and the abdominal opening remains closed. This phase lasts significantly longer than the previous and the following. In the third phase, the male stands in front of the female, but the heads do not touch, only the antennae make contact with each other. The extensions on the male antennae encompass the female antennae. At the same time, the female rubs the male pronotum with her front tarsi by alternately moving her legs forwards and backwards. In contrast to some related species, the male genitalia still remain behind the closed abdominal opening. Then the actual copulation takes place, with the male climbing onto the back of the female. The timing of the three phases of advertising is not fixed. The advertising is often broken off and replaced by non-sexual behavior or an earlier advertising phase. The only lawful thing is that the third phase takes place at most after the second, never after the first phase or spontaneously, and copulations only take place after the third phase.

distribution

The species is widespread in Europe. In southern Europe it can be found in all countries except on the islands and a few small states. In Central Europe there are only no reports from Belgium and Luxembourg, in the east of Central Europe the beetle is common, in Germany and Austria, however, it occurs only sporadically and rarely. The occurrence is limited to the north. The species is absent from the British Isles, Denmark, Norway, Finland, and the northern Russian provinces. To the east, the species is widespread with gaps as far as the Middle East and the Caucasus.

literature

Individual evidence

  1. ↑ a b c d J. David Labram, Ludwig Imhoff: Insects of Switzerland, the most excellent genres each represented by a kind. Basel, self-published 1836-45 doi: 10.5962 / bhl.title.66027 text on the genre at BHL
  2. ↑ a b Cerocoma schaefferi in Fauna Europaea. Retrieved January 27, 2014
  3. ↑ Cerocoma (subgenus) in Fauna Europaea. Retrieved January 27, 2014 and Metacerocoma (subgenus) from Fauna Europaea. Retrieved January 27, 2014
  4. ↑ a b c Cerocoma at Fauna Europaea. Retrieved January 27, 2014
  5. ↑ Pages on the genus and subgenera in BioLib Taxon Profile by Cerocoma Geoffroy , 1762
  6. ↑ Red Lists at Science4you, as of 1998
  7. ↑ Red List of Endangered Heteromera (Coleoptera: Tenebrionidea) and Teredilia (Coleoptera: Bostrichoidea) Bavaria's BayLfU / 166/2003 p. 141 [1]
  8. ↑ Carl v. Linné: Systema naturae per regna tria naturae vol. 1 10th edition Stockholm 1758 p. 420 GDZ p. 424: 420
  9. ↑ Sigmund Schenkling: Explanation of the scientific beetle names (species)
  10. ↑ Sigmund Schenkling: Explanation of the scientific beetle names (genus) .
  11. ↑ a b EL Geoffroy: Histoire abrégée des insectes qui se trouvent aux environs de Paris ... 1st volume Paris 1762 p. 357 at GDZ genus p. 391: 357
  12. ↑ ICZN 0.1754: available. Subsequent monotypy produced by Fabricius 1775: 262 (ICZN 2001: 16) from animalbase accessed on January 28, 2014
  13. ↑ L. Glaser: Natural history of the insects with special consideration of the indigenous p. 39 No. 24 preview in the Google book search
  14. ↑ Martin Schwarz: Pilot project: Basics for the protection of selected groups of insects in Upper Austria State of Upper Austria, November 2008 p. 27 p. 27
  15. ^ A b F. Turco, A. Di Giulio, MA Bologna: "Sexual and Cleaning Behavior and Related Morphology in the Genus Cerocoma (Coleoptera: Meloidae)" Journal of Insect Behavior, 16 vol. No. 2 March 2003 [2 ]

Web links

Commons : Cerocoma schaefferi  - collection of images, videos and audio files