Gnaws

from Wikipedia, the free encyclopedia
Gnaws
Schnaken (Tipula sp.) When mating

Schnaken ( Tipula sp.) When mating

Systematics
Class : Insects (Insecta)
Order : Fly (Diptera)
Subordination : Mosquitoes (Nematocera)
Partial order : Tipulomorpha
Superfamily : Tipuloidea
Family : Gnaws
Scientific name
Tipulidae
Latreille , 1802
Subfamilies
  • Ctenophorinae
  • Dolichopezinae
  • Tipulinae

The crane flies (Tipulidae) are a family in the order of Diptera (Diptera). Within this they are usually assigned to the mosquitoes (Nematocera), although their exact position in the system has not yet been clarified. However, there is a clear connection between the Tipuloidea family . The other families belonging there were traditionally regarded as subfamilies of the Schnaken and separated only late.

More common names

Regionally, Schnaken are also referred to as brook mosquitoes, horse mosquitoes, long-legged mosquitoes, tailors, wedge hoes, mosquito stallions, witches, shoemakers, Schnegger, Slak, Schnok, Amel, Emel, Purks, Pock (s), Hemel, Fräter, Sappen or Kothammel . In Bavarian Swabia they are also known as Habergaukler or Habergock (e) l .

In some of the common names of these insects is apparently to avoid confusion with belonging to the arachnids harvestmen that are regionally known also as tailors, shoemakers, death or Kanker. The term "daddy long-legs", which comes from English, sometimes appears in the German term for Schnaken as "master long leg" or "grandpa long leg". It is interesting that "daddy long-legs" are mostly gnats in Great Britain, harvestmen in the United States and large quivering spiders in Australia . In some places the term seven-eyed gnats is mistakenly applied to gnats, although this term originally referred to dragonflies , which are also not capable of stinging . The designation as mosquito stallions and the like is related to the misconception that gnats are the males of mosquitoes .

features

Around 4,000 species of snakes are known worldwide, around 140 of them in Germany. They are the largest representatives of the mosquitoes and can reach a maximum size of almost 40 millimeters in length and over 50 millimeters in wingspan ( Tipula maxima ).

Despite their size, the gnats have a very slender body and narrow wings. The body is mostly gray to brown, with some genera also drawn in yellow ( crow's snake ( nephrotoma )) or black-yellow or black-red ( crested snake ( Ctenophora )).

The wings are very often spotted black and they are usually held backwards at an angle when at rest. As with all two-winged birds, the rear wings are converted into swinging arches ( holders ). In some species, the fore wings are also stunted.

The long legs, which are often provided with predetermined breaking points and break off quickly, are striking. The antennas are designed differently for the species and consist of a different number of antenna elements for subfamilies or genera.

The head is pulled forward, the mouthparts being very soft and only capable of absorbing liquids. The rear end is clearly thickened and carries pincers in the male and an egg-layer (ovipositor) in the female, formed from the abdominal appendages ( cerci ).

Way of life

Especially in the evening the gnats often form small swarms, which are probably used to find a partner. The different species fly at very different times of the year. The cabbage schnake ( Tipula oleracea ), for example, flies from April to June and in a second generation from August to October.

The meadow snake ( Tipula paludosa ) only flies in August and September and the species Tipula czizeki only occurs in October and November. This different temporal occurrence probably represents a mechanism of species separation, since a pairing of the cabbage snake with Tipula czizeki is possible at least in the laboratory.

nutrition

Schnaken feed on exposed juices like water and nectar. They cannot ingest other food through their mouthparts. The widespread assumption that gnats “sting” humans has already been refuted by the fact that the gnats' mouthparts cannot penetrate human skin.

Reproduction

pairing

The pairing of the gnats usually takes place pretty much immediately after they have hatched from the doll's shell. In some species, the female is actually expected, but the mechanisms for recognizing this are not known. With the cabbage schnake, the mating game begins with a rather random touching of the legs, whereupon the male holds the touched leg. A female ready to mate then lifts her legs, thus inducing the male to climb. If the female is not ready to mate, it will not and the male will move away. The male pushes down the raised legs of the female and then licks the partner's head, after which it slides backwards and starts copulation . If such a pair is disturbed during the approximately 1.5-minute mating, it will fly up and remain in the copulation position.

Egg laying

The oviposition takes place soon after copulation by inserting the ovipositor, mostly in moist soil, on meadows, near water, sometimes directly in the water mud or in modern wood ( Ctenophora ). Typically, the female flies close to the ground in search of a suitable place to lay it down and stabs it with her ovipositor. In some species (such as Tipula scripta and Tipula hortorum ) the female digs a small cavity in the ground. Then it lays the eggs. In some species, the females produce several hundred eggs.

Larval development

From the eggs hatch cylindrical, mostly gray larvae without legs or other foot-like locomotion organs. Unlike the maggots of the flies, the larvae of the gnat have a head capsule, but this is (in contrast to that of a mosquito) only incompletely closed at the back (hemicephal). A striking feature of the larvae are the two rearmost tracheal openings (spiracles), which are surrounded by a dark field and six species-specific appendages. When viewed from above, these are reminiscent of a face and are therefore popularly referred to as devil's face or devil's mask. In aquatic snake larvae, these appendages collapse when submerged and thereby hold an air bubble that is used for breathing underwater. In addition to the anus, the larvae also have so-called anal papillae, which can be turned out and are used for osmoregulation .

The mandibles of the larvae are strong and crush decaying and fresh vegetable (rarely animal) material. The larvae play an important role in the processing of leaves and needles, of rotten wood in damp to wet soils or in fresh water. Few species also live in sea or brackish water. The fully grown larvae of Tipula maxima , around five centimeters long, live in forest streams and eat fallen leaves. Fermentation chambers that function as intestinal appendages that are filled with bacteria provide help in processing the hard-to-digest cellulose-rich food .

After four larval stages, these pupate, whereby a pupa with small crescents in the chest area (prothoracic cones) is formed as respiratory organs. The body is studded with thorns and the doll is posable. Pupation usually takes place in the ground or in rotten wood. In some species the pupa overwinters, in others there are two generations per year.

Harmful effect

In addition to the useful function mentioned above, the larvae of the gnat can also be harmful in mass occurrences and cause considerable damage, especially in vegetable crops. In extreme cases, up to 400 larvae per square meter can live in the soil and destroy the plantings there by feeding on the roots and feeding on the surface at night. The particularly harmful species include the meadow snake ( Tipula paludosa ), the cabbage snake ( T. oleracea ), T. czizeki and various nephrotoma species that mainly feed on young plants in the forest.

Systematics

The gnats are commonly counted among the mosquitoes (Nematocera), but this assignment is quite controversial. There is currently no agreement on the exact position of the gnats within the two-winged species. The families of the wilts (Limoniidae) and the moss mosquitoes (Cylindrotomidae) are often regarded as a subfamily of the gnat. The approximately 140 species native to Germany are commonly divided into three subfamilies with several genera.

The following species occur in Europe:

gallery

  • Head of a snake

  • As a rule, no long distances are necessary for the water supply

  • Rear end of a Schnake

  • larva

  • pairing

  • Meadow snake ( Tipula paludosa ), female

  • Giant snake ( Tipula maxima )

  • Comb snake ( Ctenophora sp.), Male

  • Female Cabbage Schnake ( Tipula oleracea , female)

Fossil evidence

Schnaken are known from various Cretaceous and Tertiary amber deposits, but nowhere often. The oldest evidence comes from Lebanon amber ( Lower Cretaceous , approx. 130 million years old), the youngest from Dominican amber (predominantly Miocene , 15 to 40 million years old). In spite of its comparatively low frequency, representatives of more than 30 genera have been described from Baltic amber , some of which still exist today, most of which are found in the Holarctic .

literature

swell

  1. ↑ László Gozmány: Vocabularium nominum animalium europae septem linguis redactum. Akadémiai Kiadó, Budapest 1979, ISBN 963-05-1381-1 .
  2. ↑ Daddy Long Legs - Bobingen. Retrieved July 9, 2020 .
  3. ↑ insektoid.info: [1] , accessed on February 13, 2011
  4. ↑ Tipulidae in Fauna Europaea. Retrieved July 19, 2011
  5. ↑ George O. Poinar: Life in Amber. Stanford University Press, Stanford 1992, ISBN 0-8047-2001-0 .
  6. ↑ Wolfgang Weitschat, Wilfried Wichard: Atlas of plants and animals in the Baltic amber. Pfeil, Munich 1998, ISBN 3-931516-45-8 .

Web links

Commons : Schnaken (Tipulidae)  - Collection of images, videos and audio files
Wiktionary: Schnake  - explanations of meanings, word origins, synonyms, translations