Common thorn insect
| Common thorn insect | ||||||||||||
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Common thorn shrimp ( Tetrix undulata ), female |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Tetrix undulata | ||||||||||||
| ( Sowerby , 1806) |
The common thorn insect ( Tetrix undulata ) is a short-antennae insect from the family of thorn insects (Tetrigidae). The species is widespread in Western and Central Europe.
features
The animals are 6 to 12 millimeters long. As with the other thorns, the basic body color is very variable. Most animals are yellow to gray-brown and have a dark marbling. The body structure is also variable with regard to the wings. Usually the pronotum and wings are shortened, but one can occasionally observe long-winged individuals with an elongated pronotum. The segments of the antennae are once or twice as long as they are wide. The thighs ( femora ) of the middle pair of legs are roughly the same length as the fore wings, the thighs of the hind legs are more than three times as long as they are wide.
The species can be confused with the similar two-spotted thorn insect ( Tetrix bipunctata ). The common thorn insect, however, has a slimmer build, the central keel of the pronotum is less bulged. The forewings are also broad and end in a blunt, asymmetrical tip, whereas T. bipunctata has narrow, elliptical forewings with a symmetrical tip. The tarsi of the hind legs in T. undulata have deep notches instead of a weak saw profile. The species can be differentiated from the long-antennae thorn insect ( Tetrix tenuicornis ) by the significantly shorter antennae and shorter wings.
Occurrence
The species is common in Europe . Their distribution ranges from Spain to France , the Benelux countries , the British Isles , Germany , Denmark , the south of Scandinavia , the south-western tip of Finland and Poland to the east to the Baltic States , Belarus , the Ukraine , Romania and the European part of Russia . The southern limit of their distribution runs through Provence , the Jura , the south of Baden-Württemberg , along the northern edge of the Alps and the north of Austria over the west of the Czech Republic and Poland. In the areas further to the east, the species occurs only sporadically and isolated. It is the most common type of family in Northern Europe.
The common thorn insect colonizes moist and cooler habitats such as moors , wet meadows , sandy heaths, sand pits and forest edges, but occasionally also occurs in poor grasslands . You need loose vegetation and small, bare ground spots.
Way of life
The animals feed on herbivores of mosses, algae and humus , less often by young grasses. The females lay their eggs from mid-May to early August in packets of 10 to 20 between mosses or in the bare ground. The nymphs take one to two years to develop. Adult males are sexually mature 14 days after the last moult.
In females there are two developmental series, depending on the photoperiod . Females that develop under long-day conditions and are adult from around the beginning of August become sexually mature in the same year and lay their eggs. The nymphs that hatch from these hibernate already in the third or fourth instar and are adult in late spring or early summer of the following year. Females that develop under short-day conditions overwinter before they become sexually mature in spring. They then lay their eggs from the end of June. The length of the day also affects the growth of the nymphs. On long days they develop quickly and without a diapause ; on short days, development is stopped in the third to fifth stage and the animals prepare for wintering. Due to these different development levels, all development stages occur simultaneously throughout the year.
Courtship and mating
As with the other thorn insects, the common thorn insect lacks stridulation organs , so that they cannot make any sounds. However, it can be assumed that they communicate via vibrations like other species of thorns. In addition, visual signals are also important during courtship. When mating, the males jump on the back of the female. If the female does not ward off the male with movements of the hind legs, mating occurs.
swell
literature
- Heiko Bellmann : Der Kosmos Heuschreckenführer, The species of Central Europe safely determine , Franckh-Kosmos Verlag GmbH & Co KG, Stuttgart 2006, ISBN 3-440-10447-8 .
- Peter Detzel: The locusts of Baden-Württemberg. Verlag Eugen Ulmer GmbH & Co, Stuttgart 1998, ISBN 3-8001-3507-8 .
Individual evidence
- ↑ Kleukers, RMJC, EJ van Nieukerken, B. Odé, LPM Willemse & WKRE van Wingerden, 1997. De sprinkhanen en krekels van Nederland (Orthoptera). Nederlandse Fauna 1. National Natuurhistorisch Museum, KNNV-Uitgeverij & EIS-Nederland. 416 p.
- ↑ Bellmann, H. (2006): The Cosmos Heuschreckenführer. Determine the species of Central Europe with certainty. - Franckh-Kosmos, Stuttgart; 350 pp.
- ↑ Petr Kočárek: Substrate-borne Vibrations as a Component of Intraspecific Communication in the Groundhopper Tetrix ceperoi . Journal of Insect Behavior, Volume 23, Number 5, 348-363, doi : 10.1007 / s10905-010-9218-8
- ↑ Axel Hochkirch, Jana Deppermann, Julia Gröning: Visual Communication Behavior as a Mechanism Behind Reproductive Interference in Three Pygmy Grasshoppers (Genus Tetrix, Tetrigidae, Orthoptera) . Journal of Insect Behavior, Volume 19, Number 5, 559-571, doi : 10.1007 / s10905-006-9043-2
