Brush horn sawfly
| Brush horn sawfly | ||||||||||
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| Argidae | ||||||||||
| Konow , 1890 |
The brush horn sawfly (Argidae) are a family of plant wasps . Of the more than 800 species worldwide, around 40 live in Europe.
features
They are small to medium-sized (mostly less than 10 mm, some up to 14 mm), compactly built wasps. The construction of the feelers is a characteristic and essential distinguishing feature. These consist of only three links, in that all the links of the antenna whip are fused into a single elongated segment. In females, this large antennae is usually thickened towards the front in a club-shaped manner. In the case of the males, only one side is covered with a dense fluff of short bristles, which the name refers to. The third antennae is greatly modified in the males of the subfamily Sterictiphorinae. Here it is split into two parallel branches (tuning fork-shaped) almost to the bottom. Incidentally, the physique is similar to that of the real sawfly . On the trunk, the front chest ( prothorax ) is quite short and drawn in in a semicircle to the rear. The Cenchri , two spots with short brooches on the upper side of the thorax that fix the wings in rest position, are usually particularly large and noticeable in them. In the genus Arge there are spurs on the legs near the front end (pre-apical), these are absent in the other genus. The anterior tibia have two terminal spurs without any special transformations. The wings usually have a conspicuous wing mark ( pterostigma ), often they are also spotted or banded. On the female's broad, usually quite short abdomen, there is an ovipositor, which is quite short and does not protrude above the abdomen when at rest. The pairs of blades that form the actual drill are fused into a saw-blade-like structure. Brush horn sawps are usually strikingly colored and marked. Many species show reds and yellows, combined with black, which serve as warning clothes. Many species have shimmering metallic colors.
Larvae
The larvae resemble caterpillars in body shape. They are soft-skinned with a round to oval, hard-sclerotized head capsule. A single-lens larval eye sits on each side of the head. Three pairs of five-limbed legs sit on the trunk. There are also short pseudopods in pairs on the abdominal segments, which are always missing on the first and eighth segment, depending on the species there are six to eight pairs. In some species there are two short, stubby appendages at the end of the body. The sides of the trunk sometimes have lobed growths. The larvae are often green in color, or they have a striking, colored warning look.
Way of life
The larvae of almost all species are free-sitting herbivores. Few, mainly American, species mine in leaves, e.g. B. Schizocerella pilicornis in leaves of purslane . A large number of different plant species are eaten. Many species eat the leaves of deciduous trees and bushes, in Central Europe mainly willows and birches . Some species specialize in roses, which are also found in gardens. Other species feed on herbaceous plant species. Almost all species specialize in one or a few related plant species ( monophag or oligophag). In many species, the larvae, which are free and sometimes in large clusters of plants, are usually protected from predators by poisonous substances (toxins). When threatened, the larvae assume a characteristic S-shaped frightened position. The poisonous effect of the hemolymph has been proven on ants.
The adults are mostly bad and lazy fliers and can be found near their host plants. Most species apparently do not ingest food in the imaginal stage. Other species visit flowers with open nectar, especially umbellifers . Some non-European species (e.g. genus Sericoceros ) stick with their egg clutch and defend it against parasitoids .
The development of the larvae to the imago can happen very quickly in many species, over the course of a few weeks. Some species, including those in the temperate latitudes, therefore have very many (four or more) generations per year.
Economical meaning
Of the numerous species in the family, only a few are known to be pests. Most species form relatively stable populations and do not tend to mass reproduce ( gradations ). The damage they cause to plants is therefore mostly minor. Some species in East Asia and North America can occasionally cause damage to forest trees, especially birch. A species introduced into Europe a few years ago, Aproceros leucopoda , causes elm baldness . Other species considered pests are Atomacera decepta on hibiscus and various Arge species on ornamental roses.
Some species of the Argidae are tested in order to contain undesirable, mostly introduced plant species as part of biological pest control. B. Atomacera petroa against the tree species Miconia calvescens introduced to Hawaii or Arge humeralis against the poison ivy ( Toxicodendron pubescens ).
Occasional cases of poisoning in domestic animals by plant wasp larvae that accidentally ingested them while eating have been reported from various countries.
Systematics and distribution
The family is spread worldwide and has its main spread in the tropics. Brush horn sawfly belong to the superfamily Tenthredinoidea . Their sister group is very likely to be the tropical family Pergidae .
Most of the 10 subfamilies only live in South America and Australia. In Europe there are representatives from two subfamilies. In the following only the genera of these subfamilies occurring in Europe are listed.
- Subfamily Arginae
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Arge - 18 species in Germany.
- Arge cyanocrocea
- Arge humeralis
- Rose-brush horn wasp ( Arge ochropus )
- Blue-black rose-brush horned sawfly ( Arge pagana )
- Arge rustica
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Arge - 18 species in Germany.
- Subfamily Sterictiphorinae
- Aprosthema - possibly 10 species in Germany (species delimitation partly uncertain)
- Sterictophora - possibly 5 species in Germany. So far, only one individual (the type specimen) has been found of a species.
- Aproceros - only one introduced species: Aproceros leucopoda
Web links
swell
- RB Benson (1951): Handbook for the identification of British insects. Vol IV Hymenoptera 2. Symphyta Section a. Published by the Royal Entomological Society of London.
- 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.
- ↑ Chester DB Hartsough, Edward F. Connor, David R. Smith, Greg S. Spicer (2003): Systematics of Two Feeding Morphs of Schizocerella pilicornis (Hymenoptera: Argidae) and Recognition of Two Species. Annals of the Entomological Society of America 100 (3): pp. 375-380. doi : 10.1603 / 0013-8746 (2007) 100 [375: SOTFMO] 2.0.CO; 2
- ^ Charles-Albert Petre, Claire Detrain, Jean-Luc Boeve (2007): Anti-predator defense mechanisms in sawfly larvae of Arge (Hymenoptera, Argidae). Journal of Insect Physiology 53: pp. 668-675.
- ↑ a b Blank, SM, Hara, H., Mikulás, J., Csóka, G., Ciornei, C., Constantineanu, R., Constantineanu, I., Roller, L., Altenhofer, E., Huflejt, T . & Vétek, G. 2010: Aproceros leucopoda (Hymenoptera: Argidae): An East Asian pest of elms ( Ulmus spp.) Invading Europe. European Journal of Entomology 107: 357-367 PDF
- ^ FR Badenes-Perez, MS Alfaro-Alpizar, A. Castillo-Castillo, MT Johnson (2008): Biological control of Miconia calvescens with a suite of insect herbivores from Costa Rica and Brazil. Proceedings of the XII International Symposium on Biological Control of Weeds, La Grande Motte, France, April 2007: 129-132.