Night flat-bellied spider

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Night flat-bellied spider
Night flat-bellied spider (Gnaphosa lucifuga), prepared female in the Zoological State Collection in Munich

Night flat-bellied spider ( Gnaphosa lucifuga ), prepared female in the Zoological State Collection in Munich

Systematics
Order : Spiders (Araneae)
Subordination : Real spiders (Araneomorphae)
Superfamily : Gnaphosoidea
Family : Flat-bellied spiders (Gnaphosidae)
Genre : Actual flat-bellied spiders ( Gnaphosa )
Type : Night flat-bellied spider
Scientific name
Gnaphosa lucifuga
( Walckenaer , 1802)

The night or dry grass flat-bellied spider ( Gnaphosa lucifuga ) is a spider from the family of flat-bellied spiders (Gnaphosidae). The Eurasian species is the largest representative of this family found in Central Europe.

features

Excerpt from The animal kingdom, arranged according to its organization, serving as a foundation for the natural history of animals: and an introduction to comparative anatomy. (1834)

The female of the night flat-bellied spider reaches a body length of 12.1 to 18.7 millimeters and the male one of 10.5 to 14.9 millimeters. This makes the species a comparatively large flat-bellied spider and, like many species in the family, has a dark color.

The prosoma (front body) has a dark red-brown to black-brown basic color, with the eye area appearing even darker. The legs have the same basic color as the prosoma, although the legs can also appear lighter. This applies particularly to the pedipalps (transformed extremities in the head area). The chelicerae (jaw claws) are darker than the prosoma.

The opisthosoma (abdomen) is dark red-brown-black-brown to black-gray in color.

Structure of the sexual organs

The bulbi (male sexual organs) of the night flat-bellied spider have strong emboli (tips of the bulbi) and also occupy the entire inside of the cymbium (import organ).

The epigyne (female genital organ) of the species has a fairly wide scapus (a structure covering the vulva) and also has side-like protrusions on the edges that fuse with the scapus.

Similar species

The two-colored flat-bellied spider ( G. bicolor ), which belongs to the same genus, is one of many species similar to the night flat-bellied spider.

In the genus of the actual flat-bellied spiders ( Gnaphosa ) there are many other species with which the night flat-bellied spider can be confused visually. The other species of the genus occurring in Central Europe are mostly much smaller and moreover lighter in color than this species. Still others are so similar to the night flat-bellied spider that they can only be distinguished from it by their genital morphological characteristics.

Occurrence

The night flat-bellied spider, which is widespread in Eurasia , has a wide range that includes Europe , Turkey , the Caucasus , Iran , Russia (European part to southern Siberia ), Kazakhstan and China .

Habitats

Limestone grasslands like this one in Belgium are among the habitats of the night flat-bellied spider.

The habitat of the night flat-bellied spider consists mainly of warm and sparsely vegetated areas with limestone soil , including dry grass , especially according to the second common name , but also rocky steppes and heaths .

Threat and protection

The night flat-bellied spider is widespread in Central Europe and not rare in some areas. However, there is still a moderate decline in the species and the night flat-bellied spider is included in the red list of endangered species animals, plants and fungi in Germany in the warning list ("V"). Before 2016, however, the species was still listed in category 3 ("endangered"), which could be corrected by increasing knowledge.

The reason for the decline is u. A. the succession (natural return of different species) of shrubs seen in former limestone landscapes. The global population of the night flat-bellied spider is not assessed by the IUCN .

Way of life

According to its first common name and like many other species in the family, the night flat-bellied spider is nocturnal, while during the day it stays under stones or the like. Like all flat-bellied spiders, it creates sack-like living webs there, which the spider uses as a place to stay when it is inactive.

In the vicinity of these webs of living space, remains of prey in the form of their chitin armor are often visible. A high number of these remains in a dungeon indicates that it will be used by the spider for a long time.

Hunting behavior

The night flat-bellied spider hunts at night according to its activity time and, like all flat-bellied spiders, does this without a safety net .

Hunting way

As with all members of the family, prey animals are perceived by the night flat-bellied spider based on their vibrations and jumped on as soon as they come within range. A poisonous bite administered with the help of the chelicerae puts them out of action. As with all members of the family, larger and / or more defensive prey animals are prevented from escaping and from being defended by a spider thread attached to them and to the ground by the spider at the same time during the jump a spider thread to the prey animal and the ground fixed and circling the prey, while the spider simultaneously produces filaments and thus prevents the prey from escaping and defending itself.

Since the remains of prey are often found near the dwarf webs of individuals of the night flat-bellied spider, it is assumed that the species either hunts in the immediate vicinity of their web or returns to it after a successful hunt with the hunted prey.

Loot spectrum

Quite well-fortified prey, which the night flat-bellied spider surpasses in terms of its dimensions, such as B. the short- domed ground beetle ( Carabus covnexus ), these regularly fall prey.

Due to its effective hunting method, the night flat-bellied spider has a large range of prey. A large part of the prey is made up of various ground beetles (Carabidae), many of which are also nocturnal and prefer the same habitats as the night flat-bellied spider. Among the ground beetles as prey, different specimens of the genera Ophonus and Harpalus as well as those of the genus the grave beetle ( Pterostichus ) could be identified. Quite fast species such as the mountain tiger beetle ( Cicindela sylvicola ) are also among the potential prey of the night flat-bellied spider. The prey composition also includes the Great Wide beetle ( Abax parallelepipedus ), the stained-colored plaster runners ( Anchomenus dorsalis ), the two-spot Cross Runner (panagaeus bipustulatus) and even the rather defensive Great bombardier beetle ( Brachinus crepitans ).

Surprisingly high sighting fell of specimens of the genus Real beetles ( carabus ), which were captured by individuals night Plattbauch spider, including the short Arched ( C. covnexus ) and the grained beetles ( C. granulatus ) that the spider with respect to their body size can clearly outperform.

Unlike some other flat-bellied spiders, such as the common ant thief ( Callilepis nocturna ), the night flat-bellied spider is not a food specialist, but an opportunistic hunter. This can be explained by the fact that the consumption of specimens of the common dust beetle ( Asida sabulosa ), the gray-winged earthbuck ( Iberodorcadion fuliginator ), the common earwig ( Forficula auricularia ) and various woodlice and weevil larvae were sighted by the spider, the same applies to specimens the field cricket ( Gryllus campestris ), the long-feeler thorn insect ( Tetrix tenuicornis ) as well as some hymenoptera such as ants , representatives of the superfamily of the Apoidea and also those of the superfamily of the Ichneumonoidea (parasitic wasps).

Life cycle

The life cycle of the night flat-bellied spider is divided into several phases and is also dependent on the season. The life cycle of this species has not yet been fully explored.

Phenology

The phenology (activity time) amounts to both sexes in the adult state in the period between May and October.

Mating and laying eggs

For mating, the male mounts the female from the front and then clasps the body with his legs. Then it first introduces one bulb and after a while it switches to the other. An eyeball can take up to an hour to transmit sperm before it is changed.

Some time after mating, the female makes an egg cocoon , which is then deposited and guarded in its web in late summer. The egg cocoon is of a white basic color and disk-shaped and has a diameter of about two centimeters.

Systematics

The night flat-bellied spider was incorporated into the genus Aranea by Charles Athanase Walckenaer in 1802, like all spiders back then , and given the name A. lucifuga . Since then, the species has undergone more taxonomic changes and therefore also renaming. The name Gnaphosa lucigufa , which is used throughout today , was given in 1868 by Tord Tamerlan Teodor Thorell , who established the new genus Gnaphosa because of its characteristic features .

The night flat-bellied spider , which is therefore the type species of the actual flat-bellied spiders ( Gnaphosa ), today has several synonyms due to the multiple descriptions .

Individual evidence

  1. ↑ a b c d e f g h i j k l Gnaphosa lucifuga (Walckenaer, 1802) from araneae Spiders of Europe, by Wolfgang Nentwig, Theo Blick, Robert Bosmans, Daniel Gloor, Ambros Hänggi & Christian Kropf, accessed on May 8 2020.
  2. ↑ a b c d e f g h i Heiko Bellmann: The cosmos spider guide. Over 400 species in Europe. Kosmos Naturführer, Kosmos (Franckh-Kosmos), 2nd edition, 2016, p. 230, ISBN 978-3-440-14895-2 .
  3. ↑ a b c Gnaphosa lucifuga (Walckenaer, 1802) at the Red List Center, accessed on May 8, 2020.
  4. ↑ a b c d e f g h Jürgen Trautner: On the prey spectrum of Gnaphosa lucifuga (Araneae: Gnaphosidae) , Arachnologische Mittellungen, Volume 7, 1994, pp. 41-44, accessed on May 8, 2020.
  5. ↑ Gnaphosa lucifuga (Walckenaer, 1802) at the Global Biodiversity Information Facility , accessed on May 8, 2020.
  6. ↑ JO Wolff, M. Řezáč, T. Krejčí, SN Gorb: Hunting with sticky tape: functional shift in silk glands of araneophagous ground spiders (Gnaphosidae) , Journal of Experimental Biology, Volume 220, 2017, pp. 2250-2259 on May 8, 2020.
  7. ↑ a b Gnaphosa lucifuga (Walckenaer, 1802) in the WSC World Spider Catalog , accessed on May 8, 2020.

literature

Web links

Commons : Night Flat-Bellied Spider  - Collection of images, videos and audio files