Giant wood wasp
| Giant wood wasp | ||||||||||||
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Giant Wood Wasp ( Urocerus gigas ), ♀ |
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| Scientific name | ||||||||||||
| Urocerus gigas | ||||||||||||
| ( Linnaeus , 1758) |
The giant wood wasp ( Urocerus gigas ) is a hymenoptera species from the family of wood wasps (Siricidae) and the largest representative of this family in Europe. The northern breed ( U. gigas taiganus ) is characterized by black ovipositories in the female and a more extensive black abdomen in the male. The giant wood wasp lays its eggs under the bark of fir and spruce trees, from where its larvae eat their way through the wood. The fir layer mushroom ( Amylostereum chailetii ), with which the giant wood wasp larva lives symbiotically and which allows it to feed on a nutrient-poor substrate such as wood, plays an important role .
features
The females are 15 to 40 millimeters long, the males, however, only 12 to 30. The head is black with two yellow spots behind the eyes. The underside of the cylindrical abdomen is black, as is the chest. The rest of the abdomen is light yellow in the female with black-violet rings, while in the male it is red with a black tip. The abdomen is parallel and has a conspicuous ovipositor in the female , but no venom apparatus.
The noise of the flight is noticeably whirring.
Occurrence
The species occurs worldwide. It is native to forest areas, but mainly to pine forests and new development areas.
Way of life
The female lays 400–500 eggs in the wood with the ovipositor . The following host species are preferred: Norway spruce ( Picea abies ) and firs ( Abies ), more rarely pine ( Pinus ), larch ( Larix ), ash ( Fraxinus ) and poplar ( Populus ) are occupied. The trees are usually parasitized in weak spots, for example in felling and back damage .
With the mucus around the eggs, spores of the fir layer fungus ( Amylostereum chailetii ) are transferred from special organs of the female, the mycetangia . The fungus decomposes the surrounding wood and thus prepares the breeding ground for the wasp larvae. The larva bores up to 40 centimeters long passages in the wood. It cannot digest cellulose; instead, in addition to the cellular constituents of the wood, it also uses fungal threads as food. The larva usually takes two to three years to develop; in some cases up to six years. The adult larva forms a pupa cradle near the bark, from which the imago gnaws its surface. The larvae use a thorn in the abdomen to block the feeding tunnels with sawdust. So it happens that the holes are not recognized even during wood processing and the insect consequently hatches out of processed wood. Because the wood is too dry after processing, there is no need to fear further infestation.
supporting documents
Individual evidence
- ^ A b c Georg Benz, Markus Zubur: The most important forest insects in Switzerland and neighboring countries . vdf Hochschulverlag AG at the ETH Zurich, 1997, ISBN 3-7281-2357-9 . P. 44.
literature
- Siegfried Rietschel: Insects. Determine accurately in three steps . BLV , Munich 2012, ISBN 978-3-8354-0943-9 .
- Michael Chinery : Parey's Book of Insects. Over 2000 insects in Europe. 2nd edition, Kosmos , Stuttgart 2012, ISBN 978-3-440-13289-0
- Georg Benz, Markus Zuber: The most important forest insects in Switzerland and neighboring countries . 2nd, updated and supplemented edition, vdf Hochschulverlag , Zurich 1997, ISBN 3-7281-2357-9 .
Web links
- Urocerus gigas at Fauna Europaea