Large alder jewel beetle
| Large alder jewel beetle | ||||||||||||
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Great Alder Beetle ( Dicerca alni ) |
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| Dicerca alni | ||||||||||||
| ( Fischer , 1824) |
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| Fig. 1: side view | |
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Fig. 2: Female, abdomen end from below |
The great alder jewel beetle ( Dicerca alni ) is a beetle from the family of jewel beetles and the subfamily Buprestinae . The rare beetle can easily be confused with the Berlin jewel beetle ( Dicerca berolinensis ).
The scientific name of the genus Dicerca is from Altgr. δι dí "two" and κέρκος kérkos "tail" derived and refers to the fact that the tail-like elongated ends of the elytra in related species gape apart. However, this property is only weakly developed in the type described here. The species name alni refers to the host plant alder ( Alnus )
Characteristics of the beetle
The 16 to 22 millimeter long body shows the typical inverted tapered shape of the jewel beetle. It is shiny bronze or greenish on the upper side, sometimes very dark, and copper-red on the lower side. The head and pronotum in particular are very coarse and irregular, sometimes with wrinkled dots. The males are characterized by strong antennae and a large tooth on the inside of the central rail in front of the center. This tooth is missing in the females and the antennae are thinner. In addition, in the female the arched section of the apical sternite is tridentate (Fig. 2), in the male it is bidentate.
The mouthparts with the strong upper jaws point downwards at an angle. The eleven-part feelers are butt-sawn on the inside. At a distance from one another, they are deflected into clear antennae sockets in front of the eyes.
The sides of the pronotum are for the most part slightly outwardly, slightly indented near the base, the front edge is narrower than the base. The central furrow of the pronotum is on average more clearly developed in the great alder beetle than in the Berlin jewel beetle. Laterally the pronotum is very dense and coarse, but very scattered dotted next to the median furrow .
On the wing covers , relatively smooth mirror spots and roughly dotted rectangular spots alternate in a row. In between there are rows of points in Dicerca alni that are visible to the naked eye. In Dicerca berolinensis, however, these are only evident next to the suture of the wing cover. The wing coverts are elongated at the back for a short tail. The tips of the wing covers are edged and the outer and inner corners of the edging are clearly drawn out like teeth (Fig. 2). The label is small and rounded, but clearly visible.
The front chest is widened backwards between the front hips (prosternal process). The prosternal process is clearly deepened in the middle, its lateral edge is smooth and raised. The broad tarsi are five-limbed, the claws imperforate.
biology
The larvae develop in dead wood, mostly in dying alders . They are also reported from common hazel , winter linden and birch , red beech (in the Apennines ) and in Greece from real walnut . The particularly warmth-loving species is a forest animal and prefers heat-exposed slopes, in the south of the distribution area also moist forests and alluvial forests. In Baden-Württemberg the current finds are below three hundred meters, in France the species is reported from about 800 meters above sea level.
The larvae develop in the sapwood of the trunk or in thicker branches. The feeding tunnels are meandering, but mostly run parallel to the longitudinal axis of the trunk. They are relatively flat, up to 15 millimeters wide and filled to the brim with fine drilling dust. The development takes several years. Shortly before pupation, the larva leads the passage out of the wood again to just under the bark, then it places the pupal chamber deeper in the sapwood. The imago leaves the pupa cradle through the last section of the corridor created by the larva. Completely developed beetles were found in the doll's cradle in October. Since the beetles appear in spring, they probably overwinter as imago. The beetles appear in Central Europe from mid-May to mid-July, but the dates of discovery vary considerably at different locations; in France, for example, the beetle appears from April to August. So it has not been decided whether the beetles will generally strip off the pupal skin in autumn and then hibernate in the pupae cradle and not leave it until the following spring.
The adults are not particularly shy and can occasionally be gripped comfortably. They usually hang out on the sunny side of logs or wooden fathers during the warm time of the day, and run about briskly in the morning and copulate. In the afternoon they sit rather sluggishly in the lower trunk area, even in the shade. They drop when approaching. Once they have fallen, they can begin to fly, or they fall to the ground and remain motionless for a long time.
Harmful effect and protection
Due to their rarity, the possible damage is insignificant for forestry. Rather, the species is listed as critically endangered in several Red Lists (Baden-Württemberg: 1; Rhineland-Palatinate: 1.1; Brandenburg: 1; Saxony-Anhalt: 1). In Switzerland , the great alder beetle is also one of the protected species of beetle.
distribution
There are largely only relic populations left. The species avoids the Atlantic area. The main distribution center is in Eastern Europe, but the species is reported from almost all European countries, North Africa and parts of Asia. There are no reports from Great Britain , the Benelux countries , Denmark , Finland , Estonia and the northern parts of European Russia . Current finds from Germany come from Bavaria , Baden , Brandenburg and Saxony-Anhalt .
literature
- Heinz Joy, Karl Wilhelm Harde, Gustav Adolf Lohse: The beetles of Central Europe . tape 6 : Diversicornia . Spectrum, Heidelberg 1979, ISBN 3-87263-027-X .
- Fritz Brechtel, Hans Kostenbader (ed.): The splendor and stag beetles of Baden-Württemberg . Ulmer, Stuttgart (Hohenheim) 2002, ISBN 3-8001-3526-4 .
Individual evidence
- ↑ a b Dicerca alni at Fauna Europaea. Retrieved August 27, 2012
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (genera)
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (species)
- ↑ H.Mühle, P. Brandl, M. Niehuis: Catalogus Faunae Graeciae; Coleoptera: Buprestidae Printed in Germany by Georg Rößle Augsburg 2000
- ↑ Klaus Koch : Die Käfer Mitteleuropas Ökologie . 1st edition. tape 2 . Goecke & Evers, Krefeld 1989, ISBN 3-87263-040-7 .
- ↑ Protection status in Switzerland ( Memento of the original from March 10, 2009 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.
