Double-eyed spruce bast beetle
| Double-eyed spruce bast beetle | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Double-eyed spruce beetle ( Polygraphus poligraphus ), female |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Polygraphus poligraphus | ||||||||||||
| ( Linnaeus , 1758) |
The double-eyed spruce beetle ( Polygraphus poligraphus ) is a weevil from the subfamily of the bark beetle (Scolytinae). Since it creates its breeding systems in the bark of the host trees, it is counted among the bark breeders.
features
The beetles are 2.2 to three millimeters long and have a brown body. The head is visible from above, the pronotum is constricted at the front and broadly indented at the front edge, finely dotted and provided with a smooth, short center line. The basal edge of the wing covers has a low tooth crest, is slightly curved and barely interrupted in the middle by the shield . The body is covered with close, short and light-colored scales. The front rails are serrated on the outside. The first and fifth sternite are the same length and larger than the second to fourth. The flattened antenna lobe , which is pointed at the end, has no seams, the antenna whip is five-membered. The eyes are divided into two parts. The third foot member is cylindrical in shape. The antennae and legs are yellowish in color.
The male has two humps on the domed, short haired forehead, the female, on the other hand, wears a fine, short ring of hair on the rather flat forehead ( sexual dimorphism ).
distribution
The species is common in Central , Northern and Eastern Europe.
Way of life
Polygraphus poligraphus occurs on Norway spruce ( Picea abies ) and Siberian spruce ( Picea obovata ), less often on pines ( Pinus ), firs ( Abies ), and larches ( Larix ). It colonizes the bark of trees and lives polygamous . Terpinen-4-ol has so far been isolated as a pheromone . The tunnels of the star-shaped brood pattern are located entirely in the bark on different levels, so that on the inside of the bark mostly only a tangle of winding larval tunnels and parts of the horizontal mother tunnels can be seen.
There is usually one generation per year, the flight time is in May / June, occasionally also in July / August. The beetles are late birds . In dry and hot years, two generations can be trained. Sibling broods, in which the old beetles come to lay a second egg, also occur. As a result, one can often find several stages of development side by side. The animals overwinter in the bark in the lower part of the trunk, but mostly in small pieces of bark that have fallen off at the base of the host trees.
Harmful effect
The beetles often attack trees in middle-aged forest stands, whereby the host trees can also die off in the event of mass reproduction. In spruce stands in unsuitable locations as well as outside the natural distribution area of the spruce and on limestone soils, the damage is sometimes more frequent and more severe than from book printers ( Ips typographus ) and engravers ( Pityogenes chalcographus ).
Pieces of bark often fall off due to woodpecker work , where the feeding pattern is clearly visible. The bark drop begins at the base of the crown . As a result, the trunk takes on a light brown bark color and can be recognized as infected from afar. The needles fall off pale green, which throws the crown out from within. The needles lie conspicuously on the forest floor around the root area.
Systematics
Synonyms
The following synonyms are known from the literature for Polygraphus poligraphus :
- Dermestes poligraphus Linné, 1758
- Polygraphus polygraphus De Geer, 1775
- Polygraphus pubescens Fabricius, 1792
- Bostrichus pubescens Fabricius, 1792
- Polygraphus pubescens var.minor Lindemann, 1875
- Polygraphus griseus Eggers, 1923
swell
Individual evidence
- ↑ Polygraphus poligraphus (Linne, 1758). Fauna Europaea, Version 1.3, April 19, 2007 , accessed on October 10, 2008 .
literature
- Fritz Schwerdtfeger : Forest diseases . Paul Parey, Hamburg and Berlin 1981, ISBN 3-490-09116-7
- Sabine Grüne : Handbook for the determination of the European bark beetles . M. & H. Schaper Verlag, Hannover 1979, ISBN 3-7944-0103-4
- Edmund Reitter : Fauna Germanica - The beetles of the German Empire . Volume 5, KG Lutz, Stuttgart 1916
- Edmund Reitter: Fauna Germanica - The beetles of the German Empire . 5 volumes, Stuttgart KG Lutz 1908 - 1916, digital library volume 134, Directmedia Publishing GmbH, Berlin 2006, ISBN 3-89853-534-7
- Evaluation and information service for food, agriculture and forestry eV ( aid ): Bark beetles, monitor and combat , 1993, forest protection working group in the AID.
