Thorn horror

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Thorn horror
Tetrix subulata

Tetrix subulata

Systematics
Class : Insects (Insecta)
Subclass : Flying insects (Pterygota)
Order : Grasshoppers (Orthoptera)
Subordination : Short-antennae terrors (Caelifera)
Superfamily : Tetrigoidea
Family : Thorn horror
Scientific name of the  superfamily
Tetrigoidea
Rambur , 1838
Scientific name of the  family
Tetrigidae
Rambur , 1838

The thorns , with the scientific name Tetrigidae , are a family in the order of the locusts (Orthoptera). They are the only family to be placed in a superfamily Tetrigoidea.

features

A typical tetrigid species that is often found on sandbanks in waters in southern Africa. The pronotum that covers the hind wings is clearly visible. The rudimentary wing can be seen above the hip (coxa) of the hind leg.
Back view. The same animal viewed from above. The massive structure of the hind legs (femora) is clear in both images.

Tetrigidae are generally relatively small grasshoppers, the body length of the European species is around 10 mm. They are usually inconspicuously colored gray or brown, often with dark spots, whereby the coloring and drawing is often very variable within the species. The integument is usually grainy or warty in structure. The coloring of the animals is camouflaged (cryptic), whereby the individual coloring and drawing can perfectly match that of the habitat and vary in parallel with it. This polyphenism is partly triggered directly by the influences of the living space and does not have to be genetically determined. Some species imitate leaves, stones or twigs with their body contour ( mimetic ). In tropical species in particular, the pronotum sometimes has conspicuous, bizarrely shaped outgrowths whose function is unknown.

The structure of the pronotum is typical and gives its name . This is extended backwards and usually covers the whole trunk, often the whole body up to the tip of the abdomen ( abdomen ), or protrudes beyond it. It runs back into a pointed thorn. The length of the mandrel is different and can be variable within the same type. The long-thorn forms have long and complete hind wings , the animals are mostly able to fly. In short-thorn species and forms, the hind wings are shortened, they are hardly or not at all capable of flight. The forewings are, as is typical for grasshoppers, designed as coarse cover wings ( tegmina ), they are always shortened in a scale-like manner, rudimentary and inoperative and partly hidden under the pronotum. One or both pairs of wings are seldom completely regressed.

The head of the thorn terrors usually has hemispherical protruding, but not very large complex eyes . There are also three point eyes ( ocelles ) that sit on the front of the head. The horizontal part of the head visible from above is called the fastigium; in most species it is set off from the rest of the forehead by a transverse quill at the tip of the head. Often the head is elongated to a point between the eyes. The pronotum and the fastigium also almost always have a longitudinal central keel, which extends forward to the forehead, which often forks downward, the lower, middle ocellus sits in this fork. The antennae are narrow and thread-shaped, with a rounded second limb ( pedicellus ), but usually quite short. They consist of 12 to 16 members in the European species. On the trunk, the abdominal plate of the first segment (Prosternum) is extended forward and surrounds the mouthparts like a collar. The legs are strongly developed, the hind legs are greatly enlarged, they give the animals, as is typical for grasshoppers, jumping ability. The rails (tibia) usually have four keels and, like the thighs, a different number of thorns. The phalanges ( tarsi ) are partially reduced or fused, two free tarsi phalanges can be seen on the front and middle legs, and three on the hind legs.

Occurrence and distribution

The species of the family are distributed almost worldwide, with the main distribution in the tropics of East Asia, Africa and South America. In Europe there are only 12 species, in Germany 6 species of the genus Tetrix . All European species belong to the genera Tetrix and Paratettix in the subfamily Tetriginae (some previously additionally differentiated genera such as Tetratetrix , Uvarovitettix , Mesotettix , Mishtshenkotetrix have been synonymous and are no longer recognized today).

Tetrigidae usually live on the ground and in the litter layer , on the banks of rivers and other bodies of water, in swamps and other humid habitats. Some species, also in Central Europe, also live in dry habitats, but then typically in open habitats with little vegetation with moss and lichen growth. They feed on algae and diatoms , detritus and mosses , among other things . The North American species Paratettix aztecus and Paratettix mexicanus, for example, feed 80 to 100% on algae as primary aquatic producers . In a study of seven tropical species from three subfamilies on Borneo, detritus, i.e. dead plant matter, was found to be the most important source of food for all species. So far, no species has been found whose food would be best based on green leaves of higher plants or which feeds on predatory food. However, the biology and ecology of almost all tropical species are so far almost unknown.

Shore species can sometimes swim on the surface of the water and like to jump into the water in case of danger. Some species of the Scelimenini tribe are fully aquatic and can swim underwater. These 70 or so aquatic species all live in tropical East Asia.

The highest biodiversity of the Tetrigidae family is found in tropical forests. There are species that live on trees, between mosses and lichens in buttress roots or in the treetops , while others live on the forest floor.

Like the other Orthoptera , the Tetrigidae go through a hemimetabolic development, whereby nymphs develop from the eggs , which already resemble the adult animals. Tetrigidae in temperate climates usually overwinter as adults (adults), less often than nymphs.

Some subfamilies of the Tetrigidae ( Batrachideinae and others) are sometimes viewed as independent families.

undefined species of the genus Hymenotes with a leaf-shaped widened pronotum.
Depressotetrix depressa
Holocerus taurus , with red parasitic mites

Phylogeny

The thorn terrors are a relatively basic branch of the short-antennae terrors. Together with the family Tridactylidae , they are considered to be the group with the most original ( plesiomorphic ) characteristics among the short-antennae terrors. According to a phylogenomic analysis from 2015 they are, after the Tridactyloidea, the earliest family to split off, with all other short-antennae terrors, collectively known as acridomorpha, as a sister group . The division into Tetrigoidea and Acridomorpha is already suspected in the Triassic . Contrary to earlier assumptions, the Tridactyloidea (with the families of Tridactylidae, Ripipterygidae and sandgroper ) and the Tetrigoidea (with the spike of terror as the only family) so probably no sister groups, the common features are Symplesiomorphien .

Systematics

Almost 2000 species are described:

Individual evidence

  1. ^ Rambur: Faune entomologique de l'Andalousie. 1838: 2:64.
  2. ↑ Hendrik Devriese (1996): Bijdrage tot de systematiek, morfologie en biologie van de West-Palearctic Tetrigidae. Saltabel 15: 2-38.
  3. ↑ a b Kurt Harz: Die Orthopteren Europe. Volume II. W. Junk Publishers, The Hague 1975. ISBN 978-94-010-1949-1 , on pages 5-9.
  4. ↑ a b D. Grimaldi, MS Engel: Evolution of the Insects. Cambridge University Press, Cambridge 2005: 211.
  5. ^ Joseph Lane Hancock: The Tettigidae of North America. Chicago, 1902. Full text source .
  6. ↑ Axel Hochkirch, Jana Deppermann, Julia Gröning (2008): Phenotypic plasticity in insects: the effects of substrate color on the coloration of two ground-hopper species. Evolution and Development 10 (3): 350-359.
  7. ^ A b K. Preston-Mafham: Grasshoppers and Mantids of the World. Facts of File, New York 1990: 32.
  8. ↑ a b Orthoptera Species File .
  9. ↑ Ming Kai Tan, Hiqing Yeo, Wei Song Hwang (2017): Ground dwelling pygmy grasshoppers (Orthoptera: Tetrigidae) in Southeast Asian tropical freshwater swamp forest prefer wet microhabitats. Journal of Orthoptera Research 26 (1): 73-80. doi: 10.3897 / jor.26.14551
  10. ↑ a b c V. H. Resh, RT Cardé: Encyclopedia of Insects. Academic Press, Amsterdam 2003: 839.
  11. ↑ JL Bastow, JL Sabo, JC Finlay, ME Power: A basal aquatic-terrestrial trophic link in rivers: algal subsidies via shore-dwelling grasshoppers. In: Oecologia 2002, 131: 261-268
  12. ↑ Kateřina Kuřatová, Jan Šipoš, Rodzaj A. Wahab, Rafiah S. Kahar, Petr Kočárek (2017): Feeding patterns in tropical groundhoppers (Tetrigidae): a case of phylogenetic dietary conservatism in a basal group of Caelifera. Zoological Journal of the Linnean Society 179: 291-302. doi: 10.1111 / zoj.12474
  13. ↑ Christiane Amédégnato & Hendrik Devriese (2008): Global diversity of true and pygmy grasshoppers (Acridomorpha, Orthoptera) in freshwater. Hydrobiologia 595: 535-543. doi: 10.1007 / s10750-007-9132-z
  14. ↑ Hojun Song, Christiane Amedegnato, Maria Marta Cigliano, Laure Desutter-Grandcolas, Sam W. Heads, Yuan Huang, Daniel Otte, Michael F. Whiting (2015): 300 million years of diversification: elucidating the patterns of orthopteran evolution based on comprehensive taxon and gene sampling. Cladistics 31: 621-651. doi: 10.1111 / cla.12116

Web links

 Wikispecies: Tetrigidae  - Species Directory
Commons : Tetrigidae  - Collection of images, videos, and audio files