Shoulder spider
| Shoulder spider | ||||||||||||
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Shoulder spider ( Araneus sturmi ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Araneus sturmi | ||||||||||||
| ( Hahn , 1831) |
The shoulder cross spider ( Araneus sturmi ) is a spider from the family of the real orb web spiders (Araneidae).
features
Males reach a body length of 3.5 millimeters and females one of 5 millimeters. The basic color is light brown to orange and has fine hairs. Seen from above, the abdomen has an almost triangular shape and is about as wide as it is long. On the front of the two sides there is a reddish-brown spot that is arched towards the rear and the border is marked by a light stripe. Behind it there is a row of bright spots on each side, which together often form a sheet-like drawing. One or two lighter arch drawings can extend between the shoulder spots. The sternum on the underside is uniformly brown, but darker than the hips . The underside of the abdomen has two yellowish longitudinal lines.
The red-brown legs are provided with light, yellowish-white ringlets and long bristles. The males have longer legs and a slimmer abdomen than the females.
Similar Art
Araneus sturmi is outwardly difficult to distinguish from Araneus triguttatus , as both species have the characteristic shoulder spots and great variability of the markings on the abdomen. A microscopic examination of the genitals is required to determine the two types with certainty. It turns out that in the males of Araneus sturmi the process (apophysis) on the tegulum of the pedipalp ends with three short tips at an even distance. In Araneus triguttatus , however, these scleritis formations have three long tips, two of which are closer together. In the females of Araneus sturmi the epigyne has an elongated scapus, in Araneus triguttatus the scapus is shorter and distally very wide.
Occurrence
The shoulder cross spider is widespread in the Palearctic and is also found in large parts of Europe up to and including Northern Europe. In some south-east European countries and in some countries in the Caucasus region it has not been detected.
It can be found on trees and bushes and inhabits mainly coniferous forests, but also isolated conifers.
Way of life
The shoulder cross spider usually builds its small orb web at a height of one to two meters on spruce, pine or juniper branches. During the day, the animals usually sit in the middle of the net, often on a branch near the net, but no additional shelter is built.
The eggs are laid a few weeks after mating. A small cocoon is spun around the eggs. The young spiders only hatch in the following spring. They feed on tiny insects.
Taxonomy and systematics
The shoulder cross spider was first described in 1831 by Carl Wilhelm Hahn in the first volume of his work The Arachniden under the name Epeira sturmii . The species name sturmi honors the natural scientist and copper engraver Jakob Sturm , who worked in Nuremberg at the same time as Hahn.
literature
- Heiko Bellman: The cosmos spider guide. Over 400 species in Europe. Kosmos Naturführer, Kosmos (Franckh-Kosmos), 1st edition, 2010, p. 136, ISBN 978-3-440-10114-8
- Carl Wilhelm Hahn : The arachnids . 1. Volume, Nuremberg 1831, p. 12 (first description) Online at www.biodiversitylibrary.org
Web links
Araneus sturmi in the World Spider Catalog
- Araneus sturmi at Fauna Europaea
Individual evidence
- ↑ a b c Araneus sturmi ( Memento of the original from July 14, 2012 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. at Araneae, Spiders of Europe, University of Bern
- ^ A b Carl Wilhelm Hahn: The arachnids . 1st volume, Nuremberg 1831, p. 12
- ↑ Araneus triguttatus ( Memento of the original of July 14, 2012 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. at Araneae, Spiders of Europe, University of Bern
- ↑ Natural History Museum of the Burgergemeinde Bern: World Spider Catalog Version 15.5 - Araneus sturmi . Retrieved September 6, 2014.
- ↑ Heiko Bellman: The cosmos spider guide. Over 400 species in Europe. Kosmos Naturführer, Kosmos (Franckh-Kosmos), 1st edition, 2010, p. 136
