Bush horn sawps
| Bush horn sawps | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Gilpinia polytoma |
||||||||||
| Systematics | ||||||||||
|
||||||||||
| Scientific name | ||||||||||
| Diprionidae | ||||||||||
| Rohwer , 1911 |
The bush horn sawfly (Diprionidae) are a family of the plant wasps (Symphyta). Their larvae develop on conifers. Some species are feared forest pests . A total of about 90 species are known.
features
It is a relatively small sawfly (approx. 5 to 10 mm long). The best distinguishing feature and eponymous is the construction of the feelers . These consist of a different number (14 to 32) of short links, which are tooth-shaped ("sawed") on the outside of the females, and broadly lamellar ("feathered" or "combed") in the males. The enlarged antenna surface of the male is used to search for the females using pheromones . The males are usually smaller and have more antennae than the females. The head is always short. The body is usually relatively compact and stocky, especially the abdomen , which sits broadly on the trunk, is usually also very short. In most other characteristics, the bush horn sawfly resemble the true sawfly (Tenthredinidae), to which they are closely related. Further characteristics concern the construction of the legs (the hips ( coxes ) of the hind legs touch each other in the middle of the body) and the wing veins (radial cell without cross vein). The wings are crystal clear and usually with a conspicuous wing mark (pterostigma) on the front edge. The ovipositor of the female is relatively short and does not protrude beyond the end of the abdomen.
Larvae
The larvae of the bush horn sawps are similar in body shape to caterpillars , they are 17 to 30 mm long. The body is soft-skinned with the exception of a round or oval head capsule. There are very short, three-part antennae on the head. A larval eye (stemma or ocularium) with a lens sits on the sides of the head. The labial palps are three- limbed , the maxillary palps four-limbed. The upper lip ( labrum ) is, similar to that of the sawfly, depressed in the middle and asymmetrically shaped, the strong mandibles below are also asymmetrical with different numbers of teeth on the right and left. On the thorax there are three pairs of legs with five limbs and a large claw. On the abdomen there are pseudopods on segments two to eight and on the tenth. The body segments are clearly curled by bulges. The larvae of the bush horned sawfly are often colored and rich in contrast. You are e.g. B. green with white vertical stripes ( Gilpinia ) or dark with yellow spots ( Diprion ), the head capsule is light brown or black. The larvae sit freely and without webs on their nutrient plants, often in large groups.
Way of life
In all species, the larvae feed on the needles of conifers. The adults take in no food at all, with the possible exception of a little water or honeydew. The larvae usually feed on a single tree species ( monophag ) or a genus ( oligophag ). Depending on the species, these are either pine ( Pinus ), spruce ( Picea ) or juniper species ( Juniperus ). Depending on the species, the larvae appear from the beginning of May to mid-June; they usually prefer older needles from the previous year, and in a few species they prefer new shoots. They grow up quite quickly, shedding their skin between five and seven times. The larvae feed individually, but in many species in large groups. When threatened, they adopt a characteristic "U" -shaped frightened position. The fully grown larvae drop to the ground and pupate on the surface of the soil or in the litter layer, in a robust, mostly double-walled cocoon, which the last larval stage spins with its labial glands. In the next spring, only some of the larvae hatch from the cocoons. Others last for two or even three years and only then hatch. Most species have one generation per year, with some species two generations can occur locally.
distribution
All species live in the northern hemisphere in a temperate (temperate) or cold (boreal) climate. Some species occur in the subtropics, none in the tropics or in the southern hemisphere.
Economical meaning
Some species are feared forest pests that can devour entire forests. Bald damage occurs particularly in pines (species: Neodiprion sertifer , Diprion pini , Gilpinia frutetorum ), less often in spruces (especially Gilpinia hercyniae ). Some species have been introduced by humans to areas outside their natural range, e.g. B. Gilpinia hercyniae to England and North America. The damage outside the natural range is z. Sometimes much larger than in the original area. After the introduction of Gilpinia hercyniae , an early attempt at biological pest control was attempted in the 1930s to introduce natural antagonists, especially hymenoptera parasitoid . Some successes were achieved, some parasitic wasp species were naturalized and contributed to the population limitation. However, a viral disease that had been brought in with breeding material completely unintentionally and initially unnoticed had a much greater effect.
Systematics
The bush horn sawps are plant wasps of the superfamily Tenthredinoidea . They are probably the sister group of the sawfly (Tenthredinidae). One view only sees them as a subfamily of the sawfly.
The following species occur in Germany:
- Subfamily Monocteninae
- Monoctenus juniperi ( Linne , 1758). Rarely on juniper, especially in the mountains, in the lowlands. Red List 3 (endangered)
- Monoctenus obscuratus ( Hartig , 1837). On junipers, in the mountains. Possibly synonymous with juniperi. Red List 3 (endangered)
- Subfamily Diprioninae
- Microdiprion pallipes ( Fallen , 1808). On pines.
- Macrodiprion nemoralis ( Enslin , 1917). On Scots pine.
- Diprion pini ( Linne , 1758). On pine.
- Diprion similis ( Hartig , 1834). On pine.
- Gilpinia abieticola ( Dalla Torre , 1894). On spruce trees.
- Gilpinia frutetorum ( Fabricius , 1793). On pines.
- Gilpinia hercyniae ( Hartig , 1837). On spruce trees.
- Gilpinia laricis ( Jurine , 1807). On Scots pine.
- Gilpinia pallida ( Klug , 1812). On Scots pine.
- Gilpinia polytoma ( Hartig , 1834). On spruce trees.
- Gilpinia socia ( Klug , 1812). On pines.
- Gilpinia variegata ( Hartig , 1834). On Scots pine.
- Gilpinia virens ( Klug , 1812). On Scots pine.
- Neodiprion sertifer ( Geoffroy , 1785). On pines.
supporting documents
Individual evidence
- ↑ P. Lyytikäinen-Saarenmaa & E. Tomppo (2002): Impact of sawfly defoliation on growth of Scots pine Pinus sylvestris (Pinaceae) and associated economic losses. Bulletin of Entomological Research 92: 137-140. doi : 10.1079 / BER2002154
- ↑ http://www.faculty.ucr.edu/~legneref/biotact/ch-48.htm
- ^ AP Rasnitsyn (1988): An outline of evolution of the hymenopterous insects (order Vespida). Oriental Insects 22: 115-145.
literature
- Wolfgang Schedl: Hymenoptera, subordination Symphyta: plant wasps, manual of zoology: Arthropoda: Insecta. Volume 4. Verlag Walter de Gruyter, 1991, ISBN 3-11-012739-3 .
- Andreas Taeger, Ewald Altenhofer, Stephan M. Blank, Ewald Jansen, Manfred Kraus, Hubert Pschorn-Walcher, Carsten Ritzau (1998): Comments on the biology, distribution and endangerment of the plant wasps in Germany (Hymenoptera, Symphyta). In: Taeger, A. & Blank, SM 1998 (Ed.): Plant wasps in Germany (Hymenoptera, Symphyta). Annotated inventory. - Goecke & Evers, Keltern, 364 + 3 pp.
- HR Wong & DL Szlabey (1986): Larvae of the North American genera of Diprionidae (Hymenoptera: Symphyta). The Canadian Entomologist 118: 577-587.
