Urocerus gigas
Giant wood wasp ( Urocerus gigas ) ♀
The giant wood wasp ( Urocerus gigas ) is a Hautflüglerart from the family of wood wasps ( Siricidae ) and the largest representative of this family in Europe. The northern race (U. gigas taiganus ) is characterized by black ovipositor sheaths in the female and a broader black abdomen of the male. The giant wood wasp lays its eggs under the bark of pine and fir trees, from where their larvae eat through the wood. An important role is played by the fir - layer mushroom ( Amylostereum chailetii ), with the giant wood wasp lives symbiotically.
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 Bottom of the cylindrical abdomen is black, so the breast. The rest of the abdomen of the female is bright yellow with black purple rings, this is the male red with black tip. The abdomen is parallel-sided and has a conspicuous ovipositor in the female, but has no venom apparatus.
The aircraft noise is noticeable buzzing.
Occurrence
The species is found worldwide. It is native to forested areas, but especially in pine forests and development areas.
Way of life
With the ovipositor the female lays 400-500 eggs into the wood. As a preferred host species: Common spruce (Picea abies) and fir (Abies ), rarely also pines ( Pinus ), larch are ( Larix), ash (Fraxinus ) and poplars (Populus ) occupied. The trees are usually parasitised on weak points, for example on felling and skidding damage.
With the mucus around the eggs spores of the fungus firs layer ( Amylostereum chailetii ) are of special organs of the female, the Mycetangien transferred. The fungus decomposes the surrounding wood and thus prepare the ground for the wasp larvae. The larva bores up to 40 centimeters long corridors in the wood. You can not digest cellulose, instead it uses next cell contents of the timber and fungal filaments as food. The development of the larva usually lasts two to three years; in some cases up to six years. The adult larva is near the bark of a doll's cradle, from which the imago eats away at the surface. The insect holes are clogged by the larva with a spike on the abdomen firmly with sawdust. So it happens that the holes are not recognized in the wood processing and consequently the insect hatches from processed wood. Because the wood after the processing is too dry, no further infestation is to be feared.