Green hay horse
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Green hay horse ( Tettigonia viridissima ), female |
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| Scientific name | ||||||||||||
| Tettigonia viridissima | ||||||||||||
| ( Linnaeus , 1758) |
The green hayhorse ( Tettigonia viridissima ), also great hay horse , great green hay horse , rarely also called green leaf insect , is one of the largest long-feeler terrors from the superfamily of leaf locusts (Tettigonioidea) found in Central Europe . The species is one of the most common leaf locusts in Central Europe.
features
The adult animals have a body length of 28 to 36 millimeters (males) or 32 to 42 millimeters (females) and are therefore significantly larger than the closely related and partly in the same area of distribution, the twittering insect ( Tettigonia cantans ). The ovipositor of the females reaches a length of another 23 to 32 millimeters. The adults , like the larvae of the seven stages of the green hay horse, are mostly monochrome green, apart from a fine brown longitudinal line on the back; animals with a yellowish tinge of legs or bodies rarely appear. The ovipositor can be recognized from the fifth larval stage, the wings of both sexes are initially formed as small protuberances from the sixth stage. When fully developed, they are very long and in the female they reach over the tip of the ovipositor. At rest the forewings completely cover the hindwings. The green hay horse is a good flyer compared to other leaf locusts.
Occurrence
The species is distributed in the Palearctic and occurs in Europe and Asia from the Atlantic to the Pacific coast . In the north the distribution extends to the south of England , Norway , Sweden and Finland , in the south over the entire Mediterranean area . In the Alpine region , the green hay horse predominantly inhabits areas below 500 m above sea level, in favorable locations it reaches 1500 m. The chirping insect occurs above it.
Are populated dry grasslands , fallow, sunny limit and edges of woods, further gardens and agricultural areas. As a cultural successor , the green hay horse also lives in human settlement areas and even in the centers of large cities, provided that suitable vegetation is available. Intensive fields and meadows are at best used as singing points in high-growth vegetation and otherwise not populated. Habitats that are warm, dry and sheltered from the wind and have at least 30 cm of vegetation are preferred; cool habitats are avoided. The larvae stay in the herb layer, as do the newly hatched adults who prefer bushes and trees later in the year.
nutrition
Both the larvae and the sexually mature green hayhorses feed mainly on predatory insects and their larvae and on weak and injured conspecifics. They also feed on a variety of plants and prefer soft and herbaceous plants.
Stridulation and stridulation organ
Only the sexually mature males utter chants that they form with their stridulation organs, which are located on the forewings. During stridulation, the two fore wings are moved against each other and hardly or not at all lifted. The females lack such organs.
Construction of the stridulation organ
Two morphologically differently shaped parts can be seen in the forewings. The large one is the part of the fore wing that is used for flying. It represents the lateral field. The other part, which represents the Dorsalfeld serves as the field cricket of Stridulation . Compared to the lateral field, the dorsal field is small, which is why the sound-forming structures are concentrated in a narrow area at the base of the wing. These structures are colored brown and stand out from the green part of the wing (picture).
singing
The singing of the males is a loud whirring, in which two rapidly successive sound impulses are separated from each other by a slightly longer interval. It can be heard from about 50 m to a maximum of 100 m. The lower call threshold is 12–16 ° C. Depending on the ambient temperature, the males are active from the afternoon until around 2 a.m. They sing in the vegetation of at least 30 cm high singing rooms and also from trees and bushes.
Hearing organ
Males and females have auditory organs ( tympanic organs ) that are located in the rails of the front legs. Outwardly, each tympanic organ presents itself as two elongated, closely arranged pits. In each a tympanic membrane (tympanum) is formed. By relocating them to caves, the tympana are protected from mechanical injuries, and directional hearing is also promoted. The tympana consist of an outer, very thin integument and the wall of a trachea, which is attached to the integument from the inside. The sensory apparatus, the auditory ridge (Crista acustica), follows inward with 32 sensory cells that are arranged in a row as scolopidia . The number of sensory cells is species-specific and therefore the same in males and females.
Reproduction
The females lay 200 to 600 eggs individually or in small groups in the ground, preferably in grassland. These are 5.3 × 1.5 millimeters in size and colored dark brown. Embryonic development takes between 1.5 and a maximum of five years. Because of the long development, it is important that the soil around the eggs does not dry out too much in the following summers. The eggs of the green hay horse are less sensitive here than those of T. cantans . The larvae go through seven stages until they molt into an adult. They hatch from around the end of April to the beginning of May. The seventh instar larvae appear in mid-July, followed by the adult hay horses by the end of October / beginning of November.
Hazard and protection
The green hay horse is widespread in Central Europe and is the most common species of the genus and is therefore not endangered.
gallery
Portrait of a green hay horse
Front (left) and back (right) views of the mandibles
Right leg of a green hay horse with hearing organ
Wings of a male. On the left wing you can see the transverse shrill strip and the mirror behind it, which is not well developed on the left.
Female in flight
Females with clearly visible spermatophores
Females laying eggs
Top view of a male
Solid yellow male
Female cub (nymph stage)
Male cub
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 .
- Rolf Schumacher: Contribution to the knowledge of the tibial tympanic organ of Tettigonia viridissima L. (Orthoptera: Tettigoniidae) . Mikoskopie 29, pp. 8-19, 1973.
- Anna Alfonsa Stark: Investigations on the sound organ of some crickets and grasshopper species, at the same time a contribution to the right-left problem . Zoological Yearbooks, Department of Anatomy and Ontogeny of Animals 77, pp. 9–50, 1958.
Web links
- Tettigonia viridissima in Fauna Europaea
- Nature in NRW
- Tettigonia viridissima at Orthoptera.ch
- Information and distribution of the green hay horse on Gartenzeitung.com
Individual evidence
- ↑ Heiko Bellmann : Der Kosmos Heuschreckenführer, Determine the types of Central Europe safely , Franckh-Kosmos Verlag-GmbH & Co KG, Stuttgart 2006, ISBN 3-440-10447-8 .
- ^ Rolf Schumacher: Contribution to the knowledge of the tibial tympanic organ of Tettigonia viridissima L. (Orthoptera: Tettigoniidae) . Mikoskopie 29, pp. 8-19, 1973.