Gravel grinder

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Gravel grinder
Gravel Wolf (Pardosa wagleri), female

Gravel Wolf ( Pardosa wagleri ), female

Systematics
Subordination : Real spiders (Araneomorphae)
Partial order : Entelegynae
Superfamily : Lycosoidea
Family : Wolf spiders (Lycosidae)
Genre : Running wolves ( Pardosa )
Type : Gravel grinder
Scientific name
Pardosa wagleri
( Hahn , 1822)

The gravel wolf ( Pardosa wagleri ) is a spider from the family of wolf spiders (Lycosidae). The species is Palaearctic used and inhabited both according to their common name gravelly shore of, but also gravel banks of flowing mountain waters.

features

The female of the gravel wolf reaches a body length of six to 8.2 and the male one of five to 5.7 millimeters. This means that the species, like many common wolves ( Pardosa ), is a smaller representative of the wolf spiders ( Lycosidae) and corresponds to the other species of the genus in terms of its basic physique.

The carapace (back shield of the prosoma or front body) is brown to dark brown in color and thickly covered with gray setae ( chitinized hair ). Because of this, living individuals of the species have an ash-gray appearance. The median (middle) longitudinal band on the carapace, which is typical for the genus, is only pronounced in the gravel wolf in the chest area and appears indistinct and yellowish red. The carapace of the species also has lateral (lateral) bands, as in the other wolves, which run narrow here and dissolve into three to five spots. These ribbons are colored yellow. Unlike other members of the genus, the eye area is not darker than other parts of the carapace and, like the rest of it, is covered with gray setae. In the much darker male, the median band is barely visible and the lateral bands also appear very reduced.

The legs are colored yellow and slightly curled. These cancellations appear brownish. Alternatively, the legs can appear spotty and not ringed, but they are always very pale. The femora (thighs) and the patellae (limbs between femora and tibia , or splints) of the male are slightly hairy frontally. The metatarsi (heel links) and especially those of the fourth pair of legs are monochrome. In addition, the male's tarsi (limbs) are evenly colored yellow.

The opisthosoma (abdomen) has a gray-black color and mostly no drawing elements. Alternatively, this part of the body can have a white, spotted collection of setae and an indistinct, yellow and lanceolate heart mark or yellowish spots, which are then indistinct. In addition, the opisthosoma occasionally bears some spots and transverse lines formed from white setae.

There is also evidence of specimens of the gravel wolf without light-colored drawing elements or grayish-yellow females, as well as almost black males.

Genital morphological features

A single bulb (male sexual organ) of the Kieslaufwolf is characterized by a tegular (back) and strongly curved apophysis. In addition, in this gender, individual segments of the pedipalps (transformed extremities in the head area) have a basic black color, although the tip of the tarsus is lighter there. The latter segment is one millimeter long and has gray setae.

The epigyne (female sex organ) of the species is unmistakable through the slim septum (partition). This can also have a more or less long handle. The septum is also 0.5 millimeters long. Furthermore, the triangular epigyne plate of the Kieslaufwolf is longer than it is wide.

Similar species

Female of the river wolf spider ( Arctosa cinerea )

The gravel wolf can in particular be confused with the mountain stream wolf ( P. saturatior ), which also belongs to the group of wolves ( Pardosa ) , but which is usually larger and has a darker color. In addition, in the male of the mountain stream running wolf, the hair on the femora and patellae on the frontal side of the legs is missing. Both species have very similarly structured genital organs, whereby those of the Gebirgsbach-Laufwolf are also correspondingly larger.

Another species within the same genus that is similar to the gravel wolf is Pardosa luctinosa . In this case, however, the daily apophysis is only slightly curved. The epigyne of P. luctinosa has a less shallow septum and a posterior (posterior) furrow.

There are also other wolf spiders (Lycosidae) that, like the gravel wolf , inhabit gravel and gravel banks and resemble them slightly due to their camouflage coloration. Examples are different species from the genus of the voles ( Arctosa ) or the pirate spiders ( Pirata ). Although representatives of the latter genus have at least mostly a body dimension similar to the gravel wolf, the species of the voles can be much larger.

Occurrence

Female in the Italian commune of Paludi ( province of Cosenza in the Calabria region )

The entire distribution area of ​​the gravel wolf extends from Europe to Turkey , the Caucasus , Russia (European part to southern Siberia ), Central Asia to China. In Europe itself the species is in Spain , France , Switzerland , Italy , Austria , Germany , Poland , Latvia , Czech Republic , Slovakia , Ukraine , the central European part of Russia, Romania , Serbia , Slovenia , Croatia , Montenegro , Albania , North Macedonia as well as in Greece and in the Middle East also detected in Georgia.

Habitats

Vegetation arm gravel banks of the Isar in Marzling ( district of Freising in Bavaria ), one of the habitats of gravel running wolf.

The gravel wolf is only represented in mountainous regions in its area of ​​distribution. According to the common name, the habitats of the species include broad banks of alpine rivers with little vegetation, which consist of gravel . The gravel grinder also lives in gravel banks on the banks of streams or rivers. The species can be found from valleys to altitudes of 1400 meters above sea level. Sandy banks are rarely used as habitat by the gravel wolf. Due to its habitat requirements, the species is considered to be hygrophilous (moisture-loving).

In Germany, suitable areas for the gravel grinder are rare. There it occurs on the banks of the Isar between Freising and Moosburg . The species is often found in the bank areas of the river that had hardly any vegetation. However, the gravel grinder was only detected in these areas in 2017. Previously, the species was only present on the banks of the Isar south of Munich.

Threat and protection

The populations of the gravel wolf are valued differently depending on the country and region. In the Red List of Threatened Species of Animals, Plants and Fungi in Germany and the Red List and Total Species List of Spiders in Germany (2016), the species is classified in category 3 (“endangered”), where it is generally considered rare. The stocks of the gravel wolf in Germany are considered to be moderately declining in the long term, while not enough data are available for short-term analyzes.

In the Red List of Spiders in Carinthia (1999), the gravel wolf is classified in category 2 (“critically endangered”), while the species in the Czech Red List according to IUCN standards is classified as CE (“Critically Endangered”) and in the Red list of Slovakia in the category in the category V ("Vulnerable") is recorded.

Way of life

The gravel wolf, like all wolf wolves ( Pardosa ), is one of the diurnal wolf spiders ( Lycosidae) and, like the other species and thus in contrast to other members of the family, does not create any living tubes. Instead, the spider lives free-roaming on the ground.

Like some other wolf spiders, the gravel wolf can also walk on the surface of the water, where it can be very noticeable due to its nimble locomotion. The species can also dive underwater. In contrast, the gravel wolf on land is well camouflaged by its color on gravel and gravel.

Hunting behavior and range of prey

The gravel wolf, like all spiders, is a predator and shares with many other wolf spiders (Lycosidae) the ability to hunt as a free-roaming ambush without a spider web . He uses his well-developed eyes to perceive prey, which can be located from a few centimeters away. Once this has happened, the spider stalks the prey and overwhelms it with sufficient proximity while jumping and a poisonous bite applied by means of the chelicerae (jaw claws) before it is consumed. Like other wolves ( Pardosa ), the gravel wolf prey on smaller insects .

Life cycle and phenology

The Isar with flooding (2013). After a body of water is flooded, the find rate of the gravel wolf in the same body of water decreases significantly in the following time.

The life cycle of the gravel wolf, like other spiders found in temperate climates, is influenced by the seasons. The same is also the case with floods in the bodies of water inhabited by the spider. If the water overflows there for a certain period of time, a lower individual density of the gravel wolf in this water is to be noted in the month following this event, which is noticeable both in the number of adult and growing specimens. A similar phenomenon is noticeable in the mountain creek pirate ( Piratula knorri ), which also belongs to the wolf spiders (Lycosidae) and lives on the banks of the water . The phenology (activity time) of the species amounts to the period between April and July in the adult individuals.

The reproductive behavior of the gravel wolf is also identical to that of other wolf spiders (Lycosidae) and thus also includes courtship behavior . This behavior, which is very similar to that of the Gebirgsbach-Laufwolf ( P. saturatior ), was examined in more detail in 2008. In the case of the gravel wolf, courtship is mainly characterized by rapid and uniform movement of the body and the pedipalps and begins with a tactical movement of the pedipalps, the intensity of which increases continuously until they have finally taken on extensive movements. The courting male lifts both pedipalps into the air at the same time before quickly lowering these extremities again. These can come into contact with the subsurface. When the female approaches, an increasingly stronger vibration of the body is noticeable in the male. In addition, it makes whipping movements with the foremost pair of legs.

For pairing occurs if the female answered the Paarungswilligkeit of the male. Mating takes place in the position typical for spiders of the superfamily of the Lycosoidea , in which the male mounts the female head-on, so that both sexual partners located on top of each other then look in the opposite direction. The male then inserts an eyeball into the epigyne of the female for the purpose of sperm transfer. The mating season for the gravel wolf is the period between spring and summer.

Female with egg cocoon

A mated female makes an egg cocoon some time after mating, but also in the same period of time, which is attached to the spinnerets , as is usual for wolf spiders, and is carried with it. After hatching, the young also climb onto their mother's opisthosoma and let them carry them for some time before separating from them. The adult animals of this generation then perish in September or October. The young hibernate in the juvenile or subadult stage and reach sexual maturity in the following year.

Systematics

Excerpt from Monographia Aranearum = monograph of the spiders (1829) by Carl Wilhelm Hahn , where the gravel wolf (below) is referred to as Lycosa wagleri .

In the field of biology, the systematics deals with the taxonomic (systematic) classification as well as with the biology and with the nomenclature (discipline of scientific naming) of living beings and thus also those of the gravel wolf.

When it was first described in 1822 by the author Carl Wilhelm Hahn, the species was named Lycosa waglerii and, like all wolf spiders ( Lycosa ) at that time, was classified in the genus Lycosa . Under Eugène Simon , the gravel wolf was classified for the first time in the genus of the barrel wolves ( Pardosa ) and at the same time received the name Pardosa wagleri , which is still valid today , which has been used continuously for the species since another use of this name by the same author in 1937.

Hahn honored with the first description called waglerii a Dr. Wagler, who made the holotype (the specimen used for the first description) available to him. At that time the gravel wolf was given the common name "Waglers-Jagdspinne" by Hahn.

Individual evidence

  1. ↑ a b c d e f g h i j k Pardosa wagleri at araneae - Spiders of Europe, accessed on March 7, 2021.
  2. ↑ a b c d e f g h i j k l Paolo Tongiorgi: Italian Wolf Spiders of the Genus Pardosa (Araneae: Lycosidae) . In: Bullentin of the Museum of Comparative Zoology . tape 134 , no. 8 , February 25, 1966, p. 301 .
  3. ^ A b D. Barthel, O. von Evesen: Pardosa wagleri (Hahn 1822) and Pardosa saturatior Simon 1937, a pair of sibling species (Araneae, Lycosidae). In: Bulletin de la Société européenne d'arachnologie. Hors-série . tape 1 , no. 1 , 1990, p. 18 .
  4. ↑ a b c Heiko Bellmann: The cosmos spider guide . Kosmos, 2016, ISBN 978-3-440-15521-9 , pp. 168 .
  5. ↑ D. Barthel, O. von Evesen: Pardosa wagleri (Hahn 1822) and Pardosa saturatior Simon 1937, a pair of sibling species (Araneae, Lycosidae). In: Bulletin de la Société européenne d'arachnologie. Hors-série . tape 1 , no. 1 , 1990, p. 22-23 .
  6. ↑ Paolo Tongiorgi: Italian Wolf Spiders of the Genus Pardosa (Araneae: Lycosidae) . In: Bullentin of the Museum of Comparative Zoology . tape 134 , no. 8 , February 25, 1966, p. 302 .
  7. ↑ a b Pardosa wagleri at the Wiki der Arachnologische Gesellschaft e. V., accessed on March 7, 2021.
  8. ↑ Michael Gebhardt, David Marek: The threatened wolf spider Pardosa wagleri extended its range north downstream the river Isar to Freising (Bavaria, Germany) . In: SPIXIANA . tape 40 , no. 1 , August 2017, ISSN  0341-8391 , p. 69-70 . , accessed March 7, 2021.
  9. ^ Pardosa wagleri at the Red List Center, accessed on March 7, 2021.
  10. ↑ Randolf Manderbach: The importance of the life cycle for the survival of the shore-dwelling wolf spider species Pardosa wagleri (HAHN, 1822) and Pirata knorri (SCOPOLl, 1763) . In: Arachnological Messages . tape 21 , April 2001, p. 6 . , accessed on March 14, 2021.
  11. ↑ Alberto Chiarle, Marco Isaia, Sergio Castellano: New findings on the courtship behavior of Pardosa wagleri (Hahn, 1822) and P. saturatior Simon, 1937 (Araneae, Lycosidae), a pair of sibling species . In: European Arachnology . ISSN  1660-9972 , p. 34 . , accessed on March 14, 2021.
  12. ↑ a b Randolf Manderbach: The importance of the life cycle for the survival of the shore-dwelling wolf spider species Pardosa wagleri (HAHN, 1822) and Pirata knorri (SCOPOLl, 1763) . In: Arachnological Messages . tape 21 , April 2001, p. 8 . , accessed on March 14, 2021.
  13. ↑ Natural History Museum of the Burgergemeinde Bern: World Spider Catalog - Pardosa wagleri . Retrieved March 14, 2021.
  14. ^ Carl Wilhelm Hahn: monograph of the spiders . In: JLS Lechnersche Buchhandlung . tape 3 , p. 2 , doi : 10.5962 / bhl.title.122225 .

literature

Web links

Commons : Kieslaufwolf  - Collection of pictures, videos and audio files