Striped timber bark beetle
| Striped timber bark beetle | ||||||||||||
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Striped timber bark beetle |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Trypodendron lineatum | ||||||||||||
| ( Olivier , 1795) |
The striped timber bark beetle ( Trypodendron lineatum , syn. Xyloterus lineatus ), also lined timber bark beetle or coniferous ambrosia beetle is a weevil from the subfamily of the bark beetle (Scolytinae). Since it creates its breeding systems in the wood of the host trees, it is assigned to the wood breeders. He's an ambrosia beetle.
features
The beetles are 2.8 to 3.8 millimeters long and have a cylindrical body. The compound eyes are divided into two parts. The pronotum is evenly arched and hides the head when viewed from above. The front edge is smooth and without a crown of cusps. It is only grained behind the front edge. The wing coverts are drawn down, finely dotted striped, finer at the fall, with black vertical stripes or surfaces. The crash is not hairy and appears dull. The abdomen remains straight from the second sternite towards the end. The third tarsal link is cylindrical in shape. The antennae lobes are broadly rounded, without seams and obovate in shape, the antennae flagella is four-part.
Male and female animals differ in appearance ( sexual dimorphism ). In the males, the pronotum is flat and humped in front, the forehead is concave and more hairy. In the female, the pronotum is arched and humped at the front, the forehead is arched and slightly hairy.
distribution
The species is common in Europe .
Way of life
The animals are monogamous , polyphagous wood breeders. The adult beetles leave the wintering places in the ground cover in spring from the end of March, when the temperature there reaches around 10 ° C. They are early birds who fly at an air temperature of 16 ° C. However, they need full brightness and calm. The beetles do not appear everywhere at the same time, as the required minimum temperature is reached later in shady places than in sunny places. Wood with bark is preferred, but debarked material is also accepted if it has the right moisture for the beetle. For example, wood felled in February or March is usually not attractive for the early swarming animals because it still contains too much water.
nutrition
Trypodendron lineatum occurs on Norway spruce ( Picea abies ) and Caucasus spruce ( Picea orientalis ), occasionally on silver fir ( Abies alba ), Nordmann fir ( Abies nordmanniana ), common pine ( Pinus sylvestris ), mountain pine ( Pinus montana ), Weymouths Pine ( Pinus strobus ), Swiss stone pine ( Pinus cembra ), European larch ( Larix decidua ) and Siberian larch ( Larix sibirica ). The beetles do not look after their brood, but indirectly their food. They drill a system of ducts into the wood in which they lay the eggs and grow an ambrosia fungus ( Leptographium lundbergii ) in it, the spores of which they carry around in their stomach. The larvae feed on the hyphae strands of the fungi.
Feeding picture and brood care
The beetles colonize the wood of the trees. The feeding pattern has an entrance tube that is driven radially into the wood. Then the brood tube is eaten across the grain, but also deviating radially again, but mostly permanently in the sapwood . This has a diameter of 1.5 millimeters. The eggs are deposited in niches that are gnawed in the direction of the fibers on both sides of the brood tube and clogged with chips. The larvae eat short brood tubes in the wood ("ladder rungs" like a single-stile ladder). These are just big enough for the larva or the later pupa to have enough space. The parents ensure the correct humidity by plugging or opening the entrance tube with drilling dust and also sort out bacterial foci and other molds.
development
Egg-laying can take weeks. Because of this and the change in the breeding line, it can appear that several generations occur each year. However, there is only one generation a year. If the first colonized breeding tree dries out more in places, for example on the upper side, the beetles leave it and fly to another place, possibly also another tree, in order to continue laying eggs. There are also subsequent broods that set in after regeneration feeding. The development from egg to adult insect takes six to ten weeks. This is followed by two to three weeks of food in the duct system. This is left from the beginning of July to mid-August in order to overwinter in the litter at a maximum distance of 30 meters from the hatchery .
Pheromone
As pheromones following compounds are known from the literature: ethanol , α-pinene , 3-hydroxy-3-methyl butan-2-one and lineatin .
Harmful effect
The drilling activity and the introduction of ragweed fungi cause technical damage in the wood, which is only of importance if the wood is stored untreated for a long time. Wood that was felled later can also be accepted if its moisture content is correct and there is already populated wood nearby. The feeding tunnels are a reason to only sell high quality sawn timber as inferior goods. Dried out and treated wood is not colonized.
Systematics
Synonyms
The following synonyms are known from the literature for Trypodendron lineatum :
- Bostrichus lineatum Olivier, 1795
- Apate bivittata Kirby, 1837
- Bostrichus cavifrons Mannerheim, 1843
- Trypodendron vittiger Eichhoff, 1881
- Xyleborus lineatus. melanocephalus Eichhoff, 1881
- Trypodendron borealis Swaine, 1917
- Trypodendron meridional Eggers, 1940
swell
Individual evidence
- ↑ Th. CH Cole: Dictionary of Invertebrates / Dictionary of Invertebrates: Latin-German-English. S. 543, Springer-Verlag, 2016. (reading sample)
- ↑ Karel Hůrka: Beetles of the Czech and Slovak Republic. Kabourek, Zlin 2005, ISBN 80-86447-04-9 .
- ^ Trypodendron lineatum (Olivier 1795). Fauna Europaea, Version 1.3, April 19, 2007 , accessed on September 23, 2008 .
literature
- Sabine Grüne : Handbook for the determination of the European bark beetles . Verlag M. & H. Schaper, Hannover 1979, ISBN 3-7944-0103-4 ,
- Karl Wilhelm Harde, Frantisek Severa and Edwin Möhn: The Kosmos Käferführer: The Central European Beetles. Franckh-Kosmos Verlags-GmbH & Co KG, Stuttgart 2000, ISBN 3-440-06959-1 .
- 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
- Fritz Schwerdtfeger: Forest diseases. Paul Parey, Hamburg and Berlin 1981, ISBN 3-490-09116-7 .
