Silvergrass heartbeat runner

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Silvergrass heartbeat runner
Silver-grass spot sapphire (Thanatus formicinus), female

Silver-grass spot sapphire ( Thanatus formicinus ), female

Systematics
Class : Arachnids (arachnida)
Order : Spiders (Araneae)
Subordination : Real spiders (Araneomorphae)
Family : Running spiders (Philodromidae)
Genre : Heart spot runner ( thanatus )
Type : Silvergrass heartbeat runner
Scientific name
Thanatus formicinus
( Clerck , 1757)

Of silver grass heart mark runners ( Thanatus formicinus ) is a web spider from the family of philodromidae (Philodromidae). Compared to other representatives of the genus, it can be found frequently.

features

male

Females of the silvergrass heartbeat reach a body length of eight to twelve, males one of five to seven millimeters. The physique is similar to that of other types of the family. The basic color of the species is light yellow-brown or gray-brown and can also appear slightly reddish. The carapace has a dark longitudinal band that is extended with a shallow covering of white hair. Next to it there are two narrow and white bands, which are flanked by two slightly wider and darker ones. As usual with the genus, the silvergrass heartbeat runner has the eponymous, distant heart-shaped and black pike spot on the opisthosoma , which is flanked here by a narrow white color. In addition, there are two tooth-like lines on the opisthosoma near the spinneret glands.

Similar species

The golden yellow flat spreader ( Philodromus aureolus ) belonging to the same family

In addition to other heart spot walkers , the silver grass heart spot walker resembles other species from the family of running spiders, for example some of the genus of the flat spider ( Philodromus ). Sure distinguishing features are the less flattened body of the silver grass heartbeat, together with the longer-lasting opisthosoma, the less flat legs and the position of the eyes. The rear median eyes of the silvergrass heartbeat have a smaller distance to each other than from the median eyes to the side eyes.

Occurrence

The silvergrass heart blotch has a large distribution area, reaching from North America over large parts of Europe and North Africa , Turkey , Caucasus , Russia (up to the eastern part of the country), Iran , Kazakhstan , Central Asia , China and Japan .

The habitat of the species is formed by open and mostly dry areas, especially dry grasslands. Occasionally, dry forest areas or humid areas with high temperatures are also accepted.

Threat and protection

Depending on the area, the silver grass heart blotch can often be found. The global inventory is not evaluated by the IUCN . In Germany the species is widespread except for northwest Germany, where it is completely absent, but has a moderate frequency with a slight decline and is included in the red list of endangered animals, plants and fungi in Germany in the warning list (V).

Way of life

The silver grass heart blotch occurs mainly on the ground or in vegetation close to the ground. Like all running spiders, it is also a free-roaming hunter who hunts prey without a safety net.

Reproduction

The courtship behavior of the silvergrass heartbeat is weak compared to other walking spiders. The actual pairing can take up to 1.5 hours. In this, the male changes several times its in the spermathecae introduced the female eyeballs . The egg cocoon made by the female some time after mating is cream-colored and its shape is reminiscent of a converging lens . The cocoon is attached to the top of leaves and guarded by the female until it hatches. The spiders then overwinter in the last young stage or in the already adult state. The activity time of the adult specimens is between March and July.

Systematics

Like all spider species described in the 18th century, the silvergrass heartbeat was initially classified in the genus Araneus (today the genus of the cross spiders belonging to the real orb web spiders (Araneidae) ) and described as A. formicinus . He also received several changes in different genres and families. Thanatus formicinus has been the consistently used scientific name for the species since 1936. The silvergrass heartbeat is the type of the genus.

gallery

  • Top view of a female

  • Lateral view of a female

Individual evidence

  1. ↑ a b c d e f g h i j Heiko Bellmann: The cosmos spider leader. Over 400 species in Europe. 2nd Edition. Kosmos Naturführer, Kosmos (Franckh-Kosmos), 2016, ISBN 978-3-440-14895-2 , p. 256.
  2. ↑ a b c d e f Description of the Silbergras-Herflecklaufers and other European running spiders on the website of "The Spiders of Europe and Greenland", accessed on December 17, 2019.
  3. ↑ a b c d e Thanatus formicinus (Clerck, 1757) from araneae Spiders of Europe, by Wolfgang Nentwig, Theo Blick, Robert Bosmans, Daniel Gloor, Ambros Hänggi & Christian Kropf, accessed on December 17, 2019.
  4. ↑ a b Thanatus formicinus (Clerck, 1757) in the WSC World Spider Catalog , accessed December 17, 2019.
  5. ↑ Thanatus formicinus (Olivier, 1789) at Global Biodiversity Information Facility , accessed December 17, 2019.
  6. ^ Threat status of the silver grass heart blotch on the website of the Red List of Germany , accessed on December 17, 2019.
  7. ↑ Mo'atsah ha-le-le'umit meḥḳar ule-fituaḥ: Israel Journal of Zoology. Weizmann Science Press of Israel, 1977, p. 212.
  8. ^ A b Dick Jones: The Country Life guide to spiders of Britain and Northern Europe. Country Life Books, 1983, ISBN 0-600-35665-5 , p. 133.
  9. ^ Robert Gale Breene: Biology, predation ecology, and significance of spiders in Texas cotton ecosystems with a key to the species. Texas Agricultural Experiment Station, Texas A&M University System, 1993, p. 21.

literature

  • Heiko Bellmann: The cosmos spider guide. Over 400 species in Europe. 2nd Edition. Kosmos Naturführer, Kosmos (Franckh-Kosmos), 2016, ISBN 978-3-440-14895-2 , p. 256.
  • Moʻatsah ha-leʼumit le-meḥḳar ule-fituaḥ: Israel Journal of Zoology. Weizmann Science Press of Israel, 1977, p. 212.
  • Dick Jones: The Country Life guide to spiders of Britain and Northern Europe. Country Life Books, 1983, ISBN 0-600-35665-5 , p. 133.
  • Robert Gale Breene: Biology, predation ecology, and significance of spiders in Texas cotton ecosystems with a key to the species. Texas Agricultural Experiment Station, Texas A&M University System, 1993, p. 21.

Web links

Commons : Silvergrass heartbeat ( Thanatus formicinus )  - Collection of images, videos and audio files