Melolontha pectoralis
| Melolontha pectoralis | ||||||||||||
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Melolontha pectoralis , female |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Melolontha pectoralis | ||||||||||||
| ( Megerle , 1812) |
Melolontha pectoralis is a beetle from the genus of cockchafer , whichbelongsto the subfamily Melolonthinae within the scarab beetles (Scarabaeidae). The genus Melolontha is represented in Europe with six species, three of which also occur in Central Europe. In contrast to the field cockchafer and the wood cockchafer, Melolontha pectoralis isvery rarein Central Europe, but elsewhere it can be quite common in places.
The species name pectoralis from Latin péctus = breast means distinguished by the breast . The generic name Melolontha ( old Gr . Μελολόντη melolónthe) referred to an insect in ancient Greece that children played with. The species is not easy to delimit because of the breadth of variation, which is why there are seventeen synonyms.
Characteristics of the beetle
The beetle has the shape of a typical cockchafer, but the tip of the abdomen ( telson ) is hardly elongated in the female. The body length of 20 to 28 millimeters is roughly the same as the body length of the field cockchafer and forest cockchafer .
The head and pronotum can be colored very differently, from black to brownish red. The upper lip and upper jaw are hidden under the head shield. The upper lip is pressed in like a slit in the middle for food intake. The compound eyes are round, large and strongly arched. The ten-segment antennae consist of a whip and an antenna fan. The strong basal segment is followed by a small second and an extended third antenna segment. In the female, the following link is already somewhat enlarged, but only the links five to ten are, like in the male, the links four to ten enlarged forward like a leaf and movable against each other and form the antennae. In the male this consists of seven members and is significantly longer than the other members of the flagellum combined, in the female the antennae consists of only six members and it is only about half as long as that of the male.
The broad pronotum is edged and has irregular light hair. It is scattered in the middle and more densely dotted on the sides .
The red-brown and irregularly hairy wing covers have four scattered dotted ribs that run parallel to the suture of the wing cover. The areas between the ribs are dense and finely dotted, coarser points are interspersed.
When viewed from below, six abdominal plates ( sternites ) are visible on the abdomen . Their rear margins are fused in the middle with the front margins of the following sternite. The respiratory openings of the abdomen are located in the laterally raised parts of the sternites. Each abdominal segment has a densely white hairy and sharply defined triangle on the side. One corner points back and down so that the entirety of the triangles forms a sawtooth curve (Fig. 1). In the female, the telson is short and rounded or truncated (Fig. 2), in the male it is elongated, but shorter and weaker than in the field cockchafer (Fig. 3). The telson is dense and fine, unevenly dotted in places and double haired, with scale-like short hair and long hair.
The front hips are cylindrical and largely sunk into the front chest, the front hip cavities are closed. The middle hips almost form a right angle to the axis of the body. The front legs are transformed into grave legs by the widening and tooth-like extensions on the outer edge of the rail . A movable mandrel on the inner edge of the front rail is not located at the end of the rail, but opposite the second tooth from the front on the outer edge. The rear rails have a recess on the upper side on the rear edge, which leads into a channel-like recess for the tarsi. In addition to this recess, there are two end pins directly next to each other on the inside. The tarsi are five-limbed, the two claws of the claw link are of the same length.
 Fig. 1: Male from Reitter , Fauna germanica |
 Fig. 2: Side view Fig. 3: Telson females  |
larva
The larvae of the genus Melolontha differ from other close-up larvae by the bristle pattern on the ventral side of the last abdominal segment. In the third larval stage, a pair of bristles runs along the middle of a bristle field, which clearly protrudes beyond the bristle field to the front. Each row consists of 21 to 30 closely spaced, short, strong and dark bristles. They run over two thirds of the length of the abdominal segment and are almost parallel, only in the area of the bristle field do they diverge slightly. Within the genus, the species is characterized by the fact that the last three (not the last four) stigmas are smaller than the previous ones. The larvae of the first stage measure an average of 2.5 centimeters, those of the second about 4.5 centimeters and the larvae of the third stage reach an average length of 6.5 centimeters.
biology
The warmth-loving species occurs in Central Europe mainly on wooded, dry southern slopes. The female lays the eggs in the ground. The larvae feed on roots. They need three to four years to develop. The adult beetles appear in late spring, later as field and forest cockchafer. Freshly hatched specimens are dusted white, but the dust disappears quickly. For the ripening feed, the beetles prefer the treetop area of young oaks that are not directly on the edge of the forest, but close to it.
distribution
The range of the thermophilic species is incoherent. The western border is in France , the southern in Italy and Greece , and southern Russia is given as the northeasternmost border . In addition to Germany , Austria , Albania , Hungary , Romania and the former Yugoslavia named, but not, for example, Switzerland and Bulgaria . The finds in Germany are isolated occurrences in southwest Germany.
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 .
- Gustav Adolf Lohse, Wilhelm H. Lucht: The beetles of Central Europe . tape 13 , 2nd supplement volume with catalog section. Goecke & Evers, Krefeld 1992, ISBN 3-87263-043-1 .
- Klaus Koch : The Beetles of Central Europe Ecology . 1st edition. tape 2 . Goecke & Evers, Krefeld 1989, ISBN 3-87263-040-7 .
Web links
Individual evidence
- ^ Systematics of the beetles in Wikipedia
- ↑ Melolontha at Fauna Europaea. Retrieved February 9, 2013
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (species)
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (genus)
- ↑ a b Melolontha pectoralis in Fauna Europaea. Retrieved February 9, 2013
- ↑ F-Th. Krell: "Determination of larvae and adults of the Central European Melolontha species (Coleoptera: Scarabaeoidea)." Laimburg Journal Vol. 1 (2), pp. 211–219, 2004 ISSN 1616-8577 as PDF ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Fleischer: Biological note on Melolontha pectoralis ( PDF )
