Ring-footed tube spider

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Ring-footed tube spider
Ring-footed tube spider (Eresus sandaliatus), male

Ring-footed tube spider ( Eresus sandaliatus ), male

Systematics
Sub-stem : Jawbearers (Chelicerata)
Class : Arachnids (arachnida)
Order : Spiders (Araneae)
Family : Tube spiders (Eresidae)
Genre : Real tube spiders ( Eresus )
Type : Ring-footed tube spider
Scientific name
Eresus sandaliatus
( Martini & Goeze , 1778)

The ring-footed tube spider ( Eresus sandaliatus ) is a spider from the family of tube spiders (Eresidae). The German-speaking common name is derived from the visual appearance of the European species, especially that of the male. Like the other species that emerged from the species complex around Eresus cinnaberinus , it is sometimes also called vermilion tube spider .

features

Subadult female

The male of the ring-footed tube spider reaches a body length of six to eleven and the female one of eight to twenty millimeters, with the prosoma (front body) accounting for four millimeters in the male and 7.9 millimeters in the female . As with the other species of the genus of the real tube spiders ( Eresus ), there is also a clear sexual dimorphism (gender difference) in the ring-footed tube spider .

The female has a basic black color. Its prosoma is black and gray and, unlike the females of other species of the genus, has no yellow forehead hair, but individual white hairs. The epigyne (female sexual organ) is almost rectangular in shape and not divided in front, the vulva is narrow anteriorly and the introductory canals are barely folded.

The male of the ring-footed tube spider, like that of the other Eresus species, is much more conspicuous in color than the female. The prosoma here is also colored black and has individual white hairs. The conductors (tip of the emboli and thus part of the bulb or male genital organs) are long and pointed distally and have a deep notch. The eponymous wrestling of the legs is particularly pronounced in the male. In contrast to the other species of the real tube spider, all legs of the male usually have a black basic color. More rarely, the two rear pairs of legs can also be colored red or have individual red hairs. For this, the male shares the red basic color of the opisthosoma (abdomen) and the dots in the form of two pairs of points with those of the other genus-related species . The male of the ring-footed tube spider has a third pair of points, which are usually much smaller than the two in front. The pairs of points are usually not outlined in this type.

Similar species

Male of the red tube spider ( Eresus kollari )

Among the many similar species of the real tube spider ( Eresus ), the ring-footed tube spider has most in common with the usually only slightly larger red tube spider ( Eresus kollari ). Differences between the two types are u. A. the third and fourth pair of legs, which are colored red in the male of the red tube spider. In addition, the male of the red tube spider only has two pairs of points on the opisthosoma, here with a white border. The females of both species are also very similar. The female of the red tube spider, however, has yellowish forehead hair, which the female of the ring-footed tube spider lacks.

Occurrence

Distribution area of ​​the ring-footed tube spider

The ring-footed tube spider found in Europe has the northernmost range of all real tube spiders. It extends from Northern Europe including the British Isles and the south of Scandinavia over the western part of Central Europe , while it ends east in the Czech Republic . In the southern Alps , the species has been detected up to a height of 2000 meters. Previous sightings of the ring-footed tube spider in the Pyrenees , Italy and Turkey turned out to be incorrect. Instead, the population observed in Turkey is likely to be a previously undescribed species from the species complex around the red tube spider. In Germany , the species has so far been detected in the Swabian Alb and in the Altmühltal .

The Süderlügumer inland dunes in Schleswig-Holstein are an example of a locality of the species .

The habitat of the species form similar to the Red bird Spider ( Eresus kollari ) dry and sandy heathlands , to take the Ringelfüßige bird Spider also stony and rocky ground on. Despite the many similarities between the preferred habitats of both species, the ring-footed spider and the red tube spider have never been found in the same area.

Threat and protection

The global population of the ring-footed tube spider is not managed by the IUCN , but as with the red tube spider ( Eresus kollari ) , there are still dwindling populations due to the decline in the habitats of both species, especially in Germany. The Red List of Endangered Species in Great Britain includes the ring-footed tube spider in the VU ("vulnerable") category. The species is very rare in Germany. It is classified in the Red List of Threatened Species of Animals, Plants and Fungi in Germany in category 2 ("endangered").

Way of life

Like other tube spiders , the ring-footed tube spider also creates a spider web typical of the family to catch prey. This consists of a horizontal net carpet, which on one side merges into cribellate catch threads and on the other ends in a dug tube about 50 to 100 millimeters into the ground, which serves as a residence for the spider. Thanks to the effective safety net, it is possible for the ring-footed tube spider to prey on very large and well-fortified prey such as ground beetles and dung beetles . As with the red tube spider ( Eresus kollari ), the ring-footed tube spider often has a high density of individuals in the same space.

Phenology and reproduction

A male tries to track down pheromones from a female

The mating season of the ring-footed tube spider runs from April to June. In terms of its reproductive behavior, the ring-footed tube spider is largely similar to the red tube spider ( Eresus kollari ). A male leaves his safety net and searches for that of a female who secretes pheromones of its own species , which the male can perceive using special organs on the front pairs of legs. For this purpose, the male holds these legs up. With the help of the pheromones, the male can find a sexual partner. Due to the conspicuous coloration, the male is conspicuous in the vegetation and can thus be easily found by possible predators (predators). If the male feels threatened, he erects his opisthosoma and makes trembling movements. Specimens of both sexes can also be found together in the female's net at the time. In the summer the female then makes a lenticular egg cocoon that can contain 35 to 80 eggs. The young animals stay with their mother and let her feed them from mouth to mouth. Shortly after hatching, it dies and serves as food for its offspring. These hibernate together in the network of the former mother before they become independent and mature in the following spring. In contrast to the red tube spider, in which the male visits a female immediately after moulting, the mature male of the ring-footed tube spider remains in his web for some time before it also seeks a partner from April.

Toxicity and bite accidents

The ring-footed tube spider is able to bite humans with its chelicerae (jaw claws). However, the bite itself does not usually cause any medically relevant consequences. There is pain in the area of ​​the bite wound, fever-like symptoms, and an increased heartbeat that subsides after an hour or two. However, it can happen that a victim of a bite experiences a severe headache for a day and the bite site is quite sensitive for a few days. If one bites the finger of a specimen of the ring-footed tube spider, the pain can radiate into the armpit.

Systematics

The species was described by Martini and Goeze in 1778 as Aranea sandaliata . In 1861 it was assigned by Blackwall as a subspecies of the red tube spider ( Eresus kollari , then known under the name Eresus cinnaberinus ). It was not until Ratschker and Bellmann that it was raised again to the rank of species as Eresus sandaliatus . In 2008, the Eresus moravicus, also previously regarded as a subspecies of the red tube spider, was granted species status. Synonyms of Eresus sandaliatus are:

  • Aranea purpurata carapace , 1804
  • Eresus annulatus Hahn , 1821
  • Erythrophorus annulatus C. L. Koch , 1850

gallery

  • Dorsal view of a male

  • Frontal view of a male

  • Lateral view of a male

  • Rear view of a male

  • Illustrations of a male animal each of the red and the ring-footed tube spider from Monographia Aranearum / Monograph of the Spiders by Carl Wilhelm Hahn (1820)

Individual evidence

  1. ↑ a b c d e f g h i j k l m n o Eresus sandaliatus (Martini & Goeze, 1778) at araneae Spiders of Europe, by Wolfgang Nentwig, Theo Blick, Robert Bosmans, Daniel Gloor, Ambros Hänggi & Christian Kropf , accessed on February 19, 2020.
  2. ↑ a b c d e f g h i j k l m n o p q r s t u Heiko Bellmann: Der Kosmos Spinnenführer. Over 400 species in Europe. 2nd Edition. Kosmos Naturführer, Kosmos (Franckh-Kosmos), 2016, ISBN 978-3-440-14895-2 , p. 64.
  3. ↑ a b c d M. Řezáč, S. Pekár, J. Johannesen: Taxonomic review and phylogenetic analysis of central European Eresus species (Araneae: Eresidae) , Zoologica Scripta 37 (3), 2008, pp. 263–287, accessed on 19th February 2020.
  4. ↑ Eresus sandaliatus (Martini & Goeze, 1778) at Global Biodiversity Information Facility , accessed on February 19, 2020.
  5. ^ RH Krause, J. Buse, A. Matern, B. Schröder, W. Haerdtle, T. Assmann: Eresus kollari (Araneae: Eresidae) calls for heathland management , Journal of Arachnology 39, 2011, pp. 384-392 on February 19, 2020.
  6. ↑ a b c Eresus sandaliatus (Martini & Goeze, 1778) at the Red List Center , accessed on February 19, 2020.
  7. ↑ Eresus sandaliatus (Martini & Goeze, 1778) at the British Arachnological Society , accessed February 19, 2020.
  8. ↑ a b Eresus sandaliatus (Martini & Goeze, 1778) in the WSC World Spider Catalog, accessed on February 19, 2020.
  9. ↑ Eresus moravicus (Řezáč, 2008) in the WSC World Spider Catalog, accessed February 19, 2020.

literature

Web links

Commons : Ring-footed tube spider  - Collection of images, videos, and audio files