Hymenoptera
From Bugwoodwiki
Csóka, György and Kovács, Tibor (1999): Xilofág rovarok - Xylophagous insects. Hungarian Forest Research Institute. Erdészeti Turományos Intézet, Agroinform Kiadó, Budapest, 189 pp.
Xylophagous insects are found in several families within the order Hymenoptera. The most important are probably the woodwasps (Siricidae). All species belong this family are xylophagous. They adults are relatively large (10-45 mm) insects with a typically cylindrical body. They are most often black sometimes with yellow rings. The females bear a long ovipositor.
The larvae are white and they have stunted thoracic legs. They develop for several years deep in the heartwood. The adult's emergence hole is circular. Most woodwasp species are known to maintain a symbiotic relationship with one or more fungus species. Spores of the fungus are introduced with the woodwasp egg, and then grow into the plant tissues. The larvae feed on the fungal tissue, and are able to digest these (rich in chitin) more easily than the cellulose and lignin of wood. The foodplant is usually killed by the fungus rather than the insects itself. The species occurring in Hungary attack mainly weakened or dying trees, therefore their forestry importance is not too serious. Several species of the family were accidentally introduced to New Zealand and Chile, where they attack healthy trees causing considerable mortality. Four genera (Urocerus, Sirex, Xeris, Tremex) of this family are known in Europe, and all of them are represented - in total with 10 species-in Hungary too. The majority of the 10 species develop in conifers, while the members of genus Tremex live in broad-leaved trees. The species belonging to the family Xiphidriidae are similar to woodwasps both in appearance and life history. The family is represented by three species in Hungary, all of which develop in broad-leaved trees. Several other hymenopteran families include xylophagous species. The larvae of Cephidae feed in young twigs and shoots of trees and shrubs. The xylophagous species of the Cynipidae and Tenthredinidae are mainly gall causing insects developing inside twigs and shoots. Species injuring the cambium often cause gall-like swellings.
