Common wolf spider

Common wolf spider
	Common wolf spider ( Arctosa cinerea )
Systematics
Class :	Arachnids (arachnida)
Order :	Spiders (Araneae)
Subordination :	Real spiders (Araneomorphae)
Family :	Wolf spiders (Lycosidae)
Genre :	Voles ( Arctosa )
Type :	Common wolf spider
Scientific name
	Arctosa cinerea
	( Fabricius , 1777)

Distribution map

Habitat of Arctosa cinerea , here the gravel bank of the Isar .

The river wolf spider ( Arctosa cinerea ), also called river bank giant wolf spider , sand wolf spider , bank voles or sand tarantula , is a spider species from the genus of the voles ( Arctosa ) within the family of the wolf spiders (Lycosidae). It is one of the largest wolf spiders in Central Europe .

description

Males of the species reach a body length of 12 to 14 millimeters, the slightly larger females from 14 to 17 millimeters. The basic color of the animals is light gray-brown to yellowish-gray, the abdomen of the males occasionally a little reddish. There is an indistinct and faded dark drawing on it, on the abdomen there are often pairs of light spots. As with all species of the genus, there is a yellow, arrow-shaped or diamond-shaped stripe in the middle of the abdomen. The legs are brightly and darkly spotted on the upper side and appear ringed, especially in the male.

As with most spiders, an examination of the mating organs is necessary for a reliable determination of the species. The upper part of the bulb of the male pedipalp has a pointed process, the tegular apophysis is triangular. In the female, the middle part of the epigyne is narrow, the front edge of the epigyne pocket is narrow. The epigynous pit is just as wide at the back as in front, the edges of the central bar are clearly set off from the front edge of the pit. A determination is possible with the identification key at Spinnen Europa.

distribution and habitat

The species is distributed in the Palearctic . It occurs throughout Europe, from Scandinavia to the Mediterranean , and east to Siberia and into Iran . There is also a dubious old information from the Congo ( Central Africa ). Old data for North America actually refer to other species, especially Arctosa littoralis ( Hentz , 1844) . It is absent in all landscapes in which its special habitat requirements are not met and is usually considered rare. It lives in dunes and on sandy sea coasts as well as on gravel banks and vegetation-free banks of rivers, in the areas that the river repeatedly encases during floods, i.e. always in habitats with little vegetation. From the bank regions it has passed into similarly structured sand or gravel pits. Thanks to its gray-brown color, it is very well camouflaged and is therefore rarely discovered, although the animals occasionally go on hunting trips during the day. Like other wolf spiders , the animals dig living tubes in the sandy ground that are padded with spider silk. The entrance is usually hidden under wood or flotsam. The residential tubes are preferably created in the deeply moist sand, about 0.5 to 1.5 meters from the shoreline.

Life cycle and way of life

The species has a two-year life cycle, which means that imaginary spiders can be found in all seasons. It is active in Central Europe between March and November. The female looks after the newly hatched young spiders between June and August, after having carried the eggs around in an egg cocoon, as is typical of the wolf spiders. The young spiders are active until October, they overwinter and only become sexually mature in late summer of the following year. They then roam freely for a period of about four weeks without building any hiding places. They do not reproduce until the spring of the following year. To overwinter, the animals leave the bank and create a wintering tube in the ground further inland. If floods occur in their habitat in summer, they close the building and wait for the water to recede in an air bubble. In a study in the Isar valley (Bavaria), a clear excess of females compared to males of around 1.8 to 1 was registered.

Taxonomy

The genus Arctosa is represented by eight species in Germany. The species forms a species group with the very similar species Arctosa variana and Arctosa similis, which are common in the Mediterranean region . The subspecies Arctosa cinerea obscura described by the Spanish arachnologist Franganillo is no longer justified today ( noun dubium ).

Others

The species is specially protected according to Appendix 1 of the Federal Species Protection Ordinance. It has become rare in Germany due to the construction of rivers and the loss of wild river landscapes and is considered endangered here. A targeted search in the state of North Rhine-Westphalia only confirmed three occurrences in the Rhine Valley. The river wolf spider was voted Spider of the Year 2007 by the Arachnological Society eV (AraGes) .

Individual evidence

↑ Heiko Bellmann: Cosmos Atlas of the arachnids of Europe. 3. Edition. Kosmos-Verlag, Stuttgart 2006, ISBN 3-440-10746-9 , p. 160.

^ W. Nentwig, T. Blick, D. Gloor, A. Hänggi, C. Kropf: Arctosa cinerea. In: Spinning Europe. Version 11.2016.

↑ Charles D. Dondale and James H. Speaker: Revision of the wolf spiders of the genus Arctosa CL Koch in North and Central America (Araneae: Lycosidae). Journal of Arachnology 11, 1983, pp. 1-30.

Jump up ↑ J. Buchar, B. Knoflach, K. Thaler: On the identity of Arctosa variana CL Koch and A. similis Schenkel with notes on related species (Araneae: Lycosidae). In: Bulletin of the British arachnological Society. 13, 2006, pp. 329-336.

^ Rainer Breitling, Tobias Bauer, Michael Schäfer, Eduardo Morano, José A. Barrientos, Theo Blick: Phantom spiders 2: More notes on dubious spider species from Europe. In: Arachnological Messages. 52, 2016, pp. 50-77.

↑ M. Kreuels, E.-F. Kiel: The river bank wolf spider in North Rhine-Westphalia: Species protection concept for a target species for species protection in NRW. In: Naturschutz-Mitteilungen NRW. 2, 2007, pp. 24-27. (PDF) ( Memento of the original from January 25, 2016 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@ 2

literature

H. Bellmann: Spinning: observing - determining. Naturbuch Verlag, Augsburg 1992, ISBN 3-89440-064-1 .
V. Framenau: Distribution and ecology of Arctosa cinerea (Aranea, Lycosidae) in alpine wild river landscapes. Philipps University, Marburg 1995.
S. Heimer, W. Nentwig: Spinning Central Europe. Parey, Hamburg / Berlin 1991, ISBN 3-489-53534-0 .
D. Jones: The Cosmos Spider Guide. Franckh-Kosmos Verlag, Stuttgart 1996, ISBN 3-440-06141-8 .
MJ Roberts: Collins Field Guide: Spiders of Britain & Northern Europe. Ramsbury, Bath 1995, ISBN 0-00-219981-5 .
M. Kreuels, M. Rezac: European Spider of the Year 2007 - The Riesenwolfspider - Arctosa cinerea (Fabricius, 1777). In: Arachnological Messages. 32, 2006, pp. 47-48. ( PDF )