Long-feeler horror

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Long-feeler horror
Wartbiter (Decticus verrucivorus), male

Wartbiter ( Decticus verrucivorus ), male

Systematics
Superclass : Six-footed (Hexapoda)
Class : Insects (Insecta)
Subclass : Flying insects (Pterygota)
Superordinate : New winged wing (Neoptera)
Order : Grasshoppers (Orthoptera)
Subordination : Long-feeler horror
Scientific name
Ensifera
Chopard , 1920

The long-feeler terrors (Ensifera) are one of the two suborders of the grasshoppers . Of the 8,100 known species , 35 species live in Central Europe . The smallest representatives with a body length of 1.5 mm can be found among the ant crickets (Myrmecophilidae). The largest within the Sägeschrecken ( Saga ) that can be mm long to 100th The largest wingspan is found in Pseudophylus collossus with a maximum of 200 mm. Many species of long-antenna terrors are predatory, others are phytophagous or consume both forms of food.

features

Characteristic features of the long-feeler terrors, which distinguish them from the types of the subordinate short-feeler terrors , are the eponymous long antennae , which often span the body length and can consist of more than 500 individual members. Only in a few species (e.g. Aganacris nitida ) are the antennae relatively short. The animals have small compound eyes and chewing-biting mouthparts . The first breast segment is particularly well developed. The fore wings are narrow and indurated and cover the larger hind wings when at rest. The females often wear a long laying pipe or a "laying saber" ( ovipositor ) at the rear end with which they lay the eggs. This consists of three pairs of appendages of the eighth and ninth abdominal segments, the gonapophyses .

Sound generation in the long-feeler terrors

At the base of the forewings, especially the males of the long-feeler terrors have a so-called stridulation organ with which they generate sounds. A thickened wing vein , which is provided with many transverse ribs, acts as a shrill vein : the cubitus posterior ; the wing surface in front of the cubitus anterior as the resonance surface. The formation of these organs is recognizable asymmetrically on both front wings (except in crickets). When singing, the superimposed front wings are moved against each other, with the shrill edge of the left front wing in the case of leaf locusts and that of the right front wing in the case of crickets being pulled over the shrill edge of the other wing.

Head and forelegs of a male spotted shrimp with clearly recognizable hearing organs

The hearing organs of the long-feeler terrors can be found in many species in the lower legs ( tibia ) of the front legs. They can lie face down or face down in pits. This "ear" is equipped with two eardrums . By differently aligning their front legs, these horrors can precisely locate other singers, especially their fellows.

The singing of the males serves primarily to attract the females, but it can also be used to establish territorial boundaries . Fighting, sometimes fatal, can occur between male field crickets. The chants are different and innate depending on the species, as is the recognition of the chants of their own species. In many species there is a mutual stimulation to sing, some species also pursue a precisely defined alternating song: they duet. The tendency to sing depends on the external factors: the wart-biter sings only during the day when the sun is strong, the green hay horse also at night.

Reaction to bats

Ultrasonic locating sounds of their predator bat can reach a volume of up to 130 dB when approached . In 2020, research by the University of Graz - in the laboratory and in the tropical rainforest of Panama - showed that locusts react to ultrasound from 80 dB with an interruption of their wing movement, they fall down a little and can thus escape bats.

Reproduction and development

Most types of long-feeler terrors find a partner through singing. Before copulation there are often courtship games with slightly modified, quieter singing by the partners. To mate, the females of the leaf locust climb on the males, in the crickets the stimulated female pushes backwards, coming from the front, under the body of the male. The male sticks a large spermatophore to the sexual opening of the female. The spermatophore can make up to 30% of the weight of the male. It is so extensive because, in addition to the actual spermatophore, a gelatinous “sperm guardian” ( spermatophylax ) is transmitted to the female. After mating, the female begins to consume the jelly of the spermatophore, which is apparently nutritious for the subsequent formation of the eggs, whereby the sperm are pressed into the seminal receptacles ( receptaculum seminis ) of the female.

Eggs are laid with the help of the ovipositor in the ground or in vegetable substrate, and the eggs are usually laid one by one. The mole crickets and some other species lay the eggs as clutches, which they maintain by licking them during further development and thus protect against fungal attack, for example.

The larval period varies in length and includes five to seven moults, with members of the Gryllus genus even more. The overwintering usually takes place as an egg or larva.

Systematics of the long-sensor terrors

In the group of long-feeler terrors, a number of subgroups (mostly referred to as superfamilies) are distinguished, some of which differ externally. The final distinction takes place via the formation of the shrill veins. Three of these subgroups are relevant for Central Europe.

Tree locusts - Tettigonioidea

The leaf locusts only have a shrill vein on the left front wing. At least in the Central European species, the foot ( tarsus ) is four-part, with the third link widened heart-shaped.

The following species of grasshopper occur in Central Europe (the classification into families and subfamilies corresponds to the system of orthoptera.speciesfile.org , but is inconsistent in the literature):

Female of the green hay horse ( Tettigonia viridissima )
Spotted shrimp on a blossom of the bee ragwort , larval stage
Green hay horse ( Tettigonia viridissima ) female , cleaning one of its long antennae

Superfamily grasshoppers - Tettigonioidea

Crickets - Grylloidea

Forest cricket ( Nemobius sylvestris ), female
Wine Grouse ( Oecanthus pellucens ), female

Both front wings of the crickets are equipped with a shrill ledge. During the generation of sounds, however, the right wing is always on top - directed diagonally upwards (in the case of chirping male locusts, the other way round, the left wing!); its shrill vein brushes the shrill edge of the lower left Elytre. The base of the crickets is only ever made up of three parts. The hind wings are also conspicuous, the ends of which protrude like spikes from under the forewings when at rest.

The following types of crickets occur in Central Europe:

Rhaphidophoroidea

Female Dolichopoda schiavazzii , a cave
shrimp from Tuscany

The last group of long-antennae terrors are the Rhaphidophoroidea . All species here are wingless in both sexes. The best-known species of this group is the greenhouse insect ( Tachycines asynamorus ) from the family of the cave horrors (Rhaphidophoridae) , which is believed to have come from China . It has been introduced into greenhouses all over the world and lives there as predatory or phytophagous. Since the 1990s there have been a few isolated occurrences of the thorned cave shrimp ( Troglophilus neglectus ) from Bavaria and Saxony in natural caves of the sandstone karst of Saxon Switzerland (KLUFTHÖHLE, Saxon. Cave cadastre no ) and in artificial cavities (e.g. in the casemates of the Königstein Fortress ). Another species is the Kollars cave shrimp ( Troglophilus cavicola ) , which occurs in Austria and Switzerland mainly in caves, but also under leaves and stones . In the Mediterranean area there are also about 20 species of the genus Dolichopoda (see also cave animals ).

literature

  • Bertrand & Hannes Baur, Christian & Daniel Roesti: The locusts of Switzerland , Haupt Verlag, Bern 2006, ISBN 3-258-07053-9 .
  • Heiko Bellmann: Locusts - observe, determine , Naturbuch-Verlag, Augsburg 1993.
  • Josef Szijj: The jumping horrors of Europe , Neue Brehm-Bücherei Vol. 652, Westarp Sciences, Hohenwarsleben 2004.

Web links

Commons : Long-probe horror  - collection of images, videos and audio files
  • Homepage of Wolfgang Rutkies: Long- feeler horror (Ensifera). In: Welcome to the animals in the garden and surroundings of Osnabrück. Retrieved March 2, 2010 .
  • OSF online

Individual evidence

  1. Crickets have sensitive hearing for bats orf.at, May 29, 2020, accessed May 29, 2020.