Argidae

Arge humeralis

The brushes Horn sawflies ( Argidae ) are a family of sawflies. About 40 of the more than 800 species worldwide live in Europe.

Features

There are small to medium-sized (usually less than 10 mm, some up to 14 mm ), compactly built sawflies. Characteristic and essential distinguishing feature is the construction of the sensor. These consist of only three members, by all the members of the sensor are merged into a single flagellum elongated segment. This large antennal segment is usually somewhat thickened club-shaped forward in the females. In the male it is only open on one side with a dense fluff short bristles, to which the name refers. Heavily modified the third antennal segment is in the males of the subfamily Sterictiphorinae. Here it is almost to the base split into two parallel branches ( tuning-fork- shaped). The conformation is similar in other respects the rights of sawflies. On the hull front chest ( prothorax ) is quite short confiscated and semi-circular back. The Cenchri, which are two spots with short small bristles on the thorax top that hold the wings at rest, are with them most particularly large and conspicuous. On the legs are located in the genus Arge spurs near the front end ( präapikal ), the absence of these other genres. The Vordertibien have two Endsporne without special transformations. The wings usually have a striking Flügelmal ( pterostigma ), they are also often spotted or banded. At the wide end ansitz, usually quite recently abdomen in the female sits an ovipositor, which is quite short and the abdomen at rest does not protrude. The the actual drill forming Valve pairs are fused into a blade type structure. Brush Horn sawflies are usually colored and marked conspicuously. Many species show red and yellow tones, combined with black, which serve as a warning costume. Many species exhibit metallic to shimmering colors.

Larvae

The larvae are similar in body shape caterpillars. You are weichhäutig with a round to oval, hard sclerotized head capsule. At the top sits on each side of a einlinsiges larval eye. On the hull sit three pairs of five-membered legs. Also on the abdomen segments sit in pairs short pseudopods, which always missing at the first and eighth segment, depending on the type, six to eight pairs available. At the end of the body there are two short, stubby like appendages in some species. The hull sides sometimes carry lobe-shaped outgrowths. The larvae are often colored green, or they have a striking, colored warning costume on.

Way of life

The larvae of almost all kinds are free sedentary herbivores. A few, especially American species nate in leaves, such as Schizocerella pilicornis in leaves of purslane. Befressen will be a variety of different plant species. Many species eat the leaves of deciduous trees and shrubs in Central Europe, especially willows and birches. Some species specialize in roses, where they are also found in gardens. Other species feed on herbaceous plant species. Almost all species are on one or a few related plant species specialized ( monophagous or oligophagous ). The free and sometimes seated in many species in the larger groupings of plants larvae are usually protected by toxins (toxins ) against herbivores. When threatened, the larvae assume a characteristic S-shaped shock position. The toxic effect of the hemolymph was detected in ants.

The adults are usually poor and sluggish fliers and can be found in the vicinity of their host plants. Most species are evident in Imaginalstadium on no food. Other species visit flowers with open dargebotenem nectar, particularly common Umbelliferae. Some non-European species (eg genus Sericoceros ) stay with their egg masses and defend it against parasitoids.

The development of the larvae up to the imago can very quickly in the course of a few weeks, run in many ways. Some species also in temperate zones have therefore many ( four or more ) generations per year.

Economic Importance

Of the numerous species of the family only a few are known as pests. Most species form relatively stable populations and are not prone to mass outbreaks ( gradations ). The damage they cause to plants are therefore predominantly low. Some species in East Asia and North America can occasionally cause damage to forest trees, especially on birch. An introduced a few years ago to Europe way Aproceros leucopoda caused defoliation on elms. Other species regarded as pests are Atomacera decepta of hibiscus and various Arge species on ornamental roses.

Some types of Argidae be tested to reduce unwanted, mostly plants brought species for biological control, such as Atomacera petroa against entrained to Hawaii tree Miconia calvescens or Arge humeralis against the poison ivy ( Toxicodendron pubescens).

From different countries poisoning cases are occasionally reported in domestic animals by sawfly larvae that had this accidentally recorded during feeding.

Systematics and distribution

The family is distributed worldwide and has its distribution area in the tropics. Brush Horn sawflies belong to the superfamily Tenthredinoidea. Their sister group is with high probability the tropical family Pergidae.

Of the total of 10 subfamilies, most live in South America and in Australia. In Europe, representatives occur in two subfamilies. In the following, only occurring in Europe genera of these subfamilies are listed.

• Subfamily Arginae Argentina - 17 species in Germany.

• Subfamily Sterictiphorinae Aprosthema - perhaps 10 species in Germany ( Artabgrenzung sometimes uncertain)
• Sterictophora - possibly 5 species in Germany. Of a kind only an individual is ( the type specimen ) has been found so far.
• Aproceros - only an introduced species: Aproceros leucopoda