Turk's thorn shrimp

from Wikipedia, the free encyclopedia
Turk's thorn shrimp
Systematics
Order : Grasshoppers (Orthoptera)
Subordination : Short-antennae terrors (Caelifera)
Family : Thorn terrors (Tetrigidae)
Subfamily : Tetriginae
Genre : Tetrix
Type : Turk's thorn shrimp
Scientific name
Tetrix tuerki
( Krauss , 1876)

Türk's thorn cricket , scientific name Tetrix Turquoise is a small thorn Fright species with habitats in wild river -Landscapes the mountains. The species is rare in the Alpine countries, very rare in Germany and in immediate danger of extinction, at times it was even considered to be extinct here.

features

Turk's thorn insect is a small species of grasshopper, males reach a body length of about 8 to 9 millimeters, females 9 to 11 millimeters. The body is almost always monochrome gray-brown, sometimes yellow- or red-brown, there are rarely but also dark-spotted or marbled animals, more often two dark spots on either side of the pronotum. The pronotum , which is distinctly thorn-like elongated to the rear, as is typical for thorn-like terrors and covers the entire trunk, is straight and not arched on the upper side (dorsal), the only slightly raised central keel has a straight upper edge in profile. The head is wider between the eyes, usually much wider than the width of the eyes, the vertex protrudes clearly beyond the front edge of the eye. The thighs (femora) of the front and middle legs are about the same width. A certain characteristic of the species is the shape of the middle and hind legs, the edge of which is clearly wavy on the underside.

The species occurs in three different forms (morphs). Short-winged (brachyptere) individuals have short hind wings, and the spine is also relatively short and does not protrude beyond the rear knees. Long-winged (macroptere) individuals have fully developed hind wings, with them the thorn protrudes far beyond the hind knees. Intermediate between them exist mesoptere individuals with medium length of thorns and hind wings. Only the macropter animals are able to fly.

Life cycle

As with most thorns, imaginal animals can be found all year round , both larvae and imagines overwinter. The animals leave the wintering quarters (outside the flooded meadow ) in April (Ukraine) to June (Alps), after the spring flood. Soon after, mating and oviposition take place. As is typical for thorns, the sexes of the species do not find each other through singing ( stridulation ) of the males. However, the males are able to send out vibration signals by vibrating the entire body; these are transmitted both as substrate sound and through direct body contact. They only serve as a signal between rival males, not to attract the sexes. The eggs are laid in the ground. The larvae appear in Ukraine from the end of May, those of the macropter form around 4 weeks later. The fifth and final larval stage is reached around the end of July. About 70 percent of the individuals then transform into adults in the same year, the rest overwinter in the last or penultimate larval instar. The overwintering larvae always develop into macropter individuals.

habitat

The species lives exclusively in the annually flooded, unobstructed floodplains of wild rivers in the mountains, at sea levels between 500 and 2,000 meters, very rarely also below (in Paşcani on the Siret river , in the Moldavian region of Romania at 200 meters). It lives on thinly overgrown sand and gravel banks surrounded by the river . These must already have a certain degree of vegetation development, but still have predominantly open, bare ground, areas with degrees of coverage above approx. 25 percent are not populated. The species is somewhat more tolerant of vegetation development than other wild river specialists such as Bryodema tuberculata and Sphingonotus caerulans . The species needs fully sunny habitats, so it only occurs on rivers, not in the narrow, mostly tree-shaded floodplains of small streams, the bottom of which in the mountains usually consists of rocks or large stones. The species avoids pure gravel banks and prefers gravel-sand mixtures or sand covers washed onto gravel banks. The highest density is achieved in small, moist depressions. Even in preferred habitats, the species only reaches a very low density of individuals and is considered difficult to detect.

In the food choice experiment, animals of the species took mosses and dead plant residues (detritus) washed up by the river as food.

distribution

Tetrix tuerki lives in the mountains of southern and southeastern Europe (Alps, Carpathians, Tatra Mountains, mountain ranges of the Balkans), south to Greece, east to the Ukrainian Carpathians. The eastern limit of the distribution is the Dniester . The western limit of the distribution is on the River Eygues near Orange (Vaucluse) in the French Prealps. An occurrence was also known in 2001 on the Çoruh in northeast Turkey. Another deposit was discovered by WHMuche near Isfara , Tajikistan ; according to the material collected here (two males), Kurt Harz presented its own subspecies Tetrix tuerki subsp. orientalis on. The only differentiating feature is the fastigium (the part of the forehead protruding between the eyes), which protrudes less in these.

Endangerment and nature conservation

Turk's thorn insect is now threatened in almost its entire area by the blockage of wild rivers. The species can only survive in river beds with natural runoff dynamics, with constant relocation of material through floods. These habitats are threatened by agricultural amelioration , settlement and road construction, sand and gravel mining and the construction of dams, but in recent refuges they are also increasingly threatened by tourism. The species is unable to move to secondary habitats such as gravel and sand pits. All German occurrences are in Bavaria (the species probably never occurred in Baden-Württemberg). Here, too, it is threatened with extinction according to the current Red List (Category 1). In Switzerland, the already worrying population situation in 1994 had deteriorated further by 2007, the species is also threatened with extinction here. In Austria, on the other hand, the situation is considered somewhat better, because at least the large occurrence on the Lech in Tyrol is considered relatively secure. Numerous occurrences, for example all in the east of the country, have also died out here.

Individual evidence

  1. ^ German name after Peter Detzel (1995): On the nomenclature of grasshoppers and catching horrors in Germany. Articulata 10 (1): 3-10.
  2. ^ Kurt Harz: Geradflügler or Orthoptera. In: Friedrich Dahl (founder): The animal world of Germany and the adjacent parts of the sea. 44th part. Gustav Fischer Verlag, Jena 1960.
  3. ↑ Heiko Bellmann: Observe and determine locusts. Naturbuch-Verlag Augsburg, 2nd edition, 1993. ISBN 3-89440-028-5
  4. ↑ a b c d e T.I, Pushkar (2009): Tetrix tuerki (Orthoptera, Tetrigidae): distribution in Ukraine, ecological characteristic and features of biology. Vestnik zoologii 43 (1): e1 – e14. doi : 10.2478 / v10058-009-0001-2
  5. ↑ a b Berthold Janssen, Randolf Manderbach, Michael Reich (1996): Distribution and threat of Tetrix Turquoise (KRAUSS, 1876) in Germany. Articulata 11 (1): 81-86.
  6. ↑ Ionuţ Ştefan Iorgu (2008): The Orthoptera fauna (Insecta: Orthoptera) from Paşcani and surroundings (Romania, Iaşi County). Analele Ştiinţifice ale Universităţii “Al. I. Cuza “Iaşi, s. Biology animala 54: 73-80.
  7. ^ Tockner, K., Paetzold, A., Karaus, U., Claret, C., Zettel, J. (2009): Ecology of Braided Rivers. In GH Sambrook Smith, JL Best, CS Bristow, GE Petts (editors): Braided Rivers: Process, Deposits, Ecology and Management, Blackwell Publishing Ltd., Oxford, UK. doi : 10.1002 / 9781444304374.ch17 , p.16
  8. ↑ Bernard Defaut (1997): Localités orthoptériques intéressantes en France continentale. L'Entomologiste 53 (1): 1-8.
  9. ↑ Arne W. Lehmann & Ingmar Landeck (2009): Pygmy grasshoppers (Orthoptera: Tetrigidae) from North-eastern Turkey. Articulata 22 (2): 225-234.
  10. ↑ Kurt Harz (1979): Two new Tetrix subspecies from Tajikistan (Orthoptera, Tetrigidae). Articulata 1 (13): 127-128. download ( Memento of the original from July 14, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.dgfo-articulata.de
  11. ↑ Stephan Maas, Peter Detzel, Aloysius Staudt: Risk analysis of the grasshoppers in Germany. Dissemination atlas, risk classification and protection concepts. published by the Federal Agency for Nature Conservation, Bonn-Bad Godesberg 2002. ISBN 3-7843-3828-3
  12. ↑ Peter Detzel: The locusts of Baden-Württemberg. Eugen Ulmer Verlag, 1998. ISBN 3-8001-3507-8 . p.92
  13. ↑ Gerd Heusinger: Red list of endangered jumping horrors (Saltatoria) Bavaria. Published by the Bavarian State Office for the Environment 2003. download
  14. ↑ Christian Monnerat, Philippe Thorens, Thomas Walter, Yves Gonseth: Red List Heuschrecken - Red List of Endangered Species in Switzerland, 2007 edition. Published by the Federal Office for the Environment FOEN and the Swiss Center for the Cartography of Fauna SZKF / CSCF Bern, 2007.
  15. ↑ Klaus-Peter Zulka: Red Lists of Endangered Animals in Austria: Mammals, birds, grasshoppers, water beetles, netwings, beaked flies, butterflies. Published by the Federal Ministry for Agriculture, Forestry, Environment and Water Management. Böhlau Verlag, Vienna 2005. ISBN 978-3-205-77345-0 p.201 preview on Google Books

Web links