Actual extensor spiders

Actual extensor spiders
Mountain Trekker Spider ( Tetragnatha montana )
Systematics
Subordination : Real spiders (Araneomorphae) Partial order : Entelegynae Superfamily : Orb web spiders (Araneoidea) Family : Extender spiders (Tetragnathidae) Genre : Actual extensor spiders
Scientific name
Tetragnatha
Latreille , 1804

The authentics Strecker spider ( Tetragnatha ), simply Strecker spider called, are a genus of the spider family , which also Strecker spider (Tetragnathidae) is called. They comprise 330 species worldwide. (As of June 2020)

There is a risk of confusion with other species in their family due to the unclear and inconsistent German naming, as many species are often also called extensor spiders.

distribution

The main distribution area are the tropics and subtropics . In Europe, only a few species are common, all in near waters in bogs or in moist forests occur. They are extremely numerous in the extensive lake areas and swamp forests of northeast Germany.

description

Actual extensor spiders have an elongated and narrow, to rod-shaped abdomen (opisthosoma). They stretch out in case of danger and put the front pair of legs together forwards and the back legs backwards so that they are very well camouflaged on stalks, leaves and twigs. Many species stay on the underside of reed leaves during the day and are therefore very difficult to spot.

In addition to this camouflage, they have another adaptation to their habitats. You can e.g. B. use the surface tension of the water and, in an emergency, walk over the water, as can the gerandete hunting spider ( Dolomedes fimbriatus ) and some wolf spiders such as pirata species. Like other members of the thick-jawed spider family , they build wheel nets with an open hub.

Reproduction

The pairing of the real extensor spiders is similar to that of many real spiders . To fill the palps, the male weaves a triangular, horizontal sperm net . First, sperm drops are released on the upper side of the sperm network by rocking the abdomen. Then the male climbs onto the underside of the net and fills his bulbi with the sperm; probably with the help of capillary forces. The palps are salivated beforehand.

Native species and their habitats

German name	Scientific name	Distribution and habitat
	Tetragnatha dearmata Thorell , 1873	holarctic
Common extensor spider	Tetragnatha extensa ( Linnaeus , 1758)	Holarctic, Madeira; frequently; Herb and shrub layers, coasts, moors, fresh meadows and forests, but also in grain fields.
Mountain trek spider	Tetragnatha montana ( Simon , 1874)	palaearctic; Rare; on lakes and moors, in reeds, soil, herbaceous and shrub layers.
	Tetragnatha nigrita Lendl , 1886	palaearctic
	Tetragnatha obtusa C. L. Koch , 1837	palaearctic; in orchards , moderately dry to moist forests and similar cultural biotopes, often in the canopy of the trees.
	Tetragnatha pinicola L. Koch , 1870	Palearctic, but so far only in Eastern Europe and Scandinavia; in all strata rarely on the ground, meadows, forests, especially in grain fields.
	Tetragnatha reimoseri ( Rosca , 1939)	Eastern Europe to Berlin, Brandenburg and Western Pomerania; in reeds.

species

The World Spider Catalog lists 336 species for the actual spider spiders . (As of December 2016)

literature

• Heimer & Nentwig: Spiders of Central Europe. Paul Parey, Berlin 1991. ISBN 3-489-53534-0 .
• Hänggi, Stöckli & Nentwig: Habitats of Central European Spiders. Misc. Faun. Helvetiae, Center suisse de cartographie de la faune. Neuchâtel / Bern 1995. ISBN 2-88414-008-5 .

Individual evidence

1. ↑ ^{a b} Natural History Museum of the Burgergemeinde Bern: World Spider Catalog Version 17.5 - Tetragnatha . Retrieved December 23, 2016.

Web links

Commons : Actual extensor spiders ( Tetragnatha )  - collection of images, videos and audio files

Tetragnatha in the World Spider Catalog