South Russian tarantula

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South Russian tarantula
South Russian tarantula (Lycosa singoriensis), female

South Russian tarantula ( Lycosa singoriensis ), female

Systematics
Class : Arachnids (arachnida)
Order : Spiders (Araneae)
Subordination : Real spiders (Araneomorphae)
Family : Wolf spiders (Lycosidae)
Genre : Lycosa
Type : South Russian tarantula
Scientific name
Lycosa singoriensis
( Laxmann , 1770)

The South Russian or Russian tarantula ( Lycosa singoriensis , Syn . : Allohogna singoriensis ) is a spider within the family of wolf spiders (Lycosidae). The range of the species covers large parts of the Eurasian steppe and reaches west to the Seewinkel in the east of Austria . With a body length of up to 40 millimeters in females, the South Russian tarantula is not only the largest species of spider found in Central Europe , but also one of the largest in Europe.

The nocturnal South Russian tarantula, like some other wolf spiders, digs burrows in which it spends most of the day and which it leaves at night to forage. Like most members of the family, the species hunts freely as a stalker , i.e. without a spider web . In doing so, it preyes on other arthropods as well as smaller vertebrates . The reproductive behavior of the species is also identical to that of other wolf spiders, including the typical family courtship on the part of the male. The female then carries her egg cocoon, which was made some time after mating, also attached to the spinnerets like other wolf spiders, and the young climb after hatching on the opisthosoma (abdomen) of the mother, where they remain for some time before they become independent grow up.

The South Russian tarantula, like the other larger spider species called " tarantula " (predominantly other wolf spiders and individual tarantulas (Theraphosidae), incorrectly due to the incorrect translation of the English word tarantula for "tarantula", the entire latter family) has a certain prominence. It is also feared, but by far not as strong as the Apulian ( L. tarentula ) or the black-bellied tarantula ( Hogna radiata ), which belong to the same genus . As with these, the bite of the South Russian tarantula and its effects on humans are not of medical relevance.

features

male

The female of the South Russian tarantula reaches a body length of 18 to 40 (mostly 35 ± 6) millimeters and a weight of 2.6 to 7 grams, making the species not only the largest spider found in Central Europe, but also one of them Deserta tarantula ( Hogna ingens ), which counts wolf spiders, and the Greek tube spider ( Eresus walckenaeri ), which belongs to the family of tube spiders (Eresidae) , whose females can reach the same body length, one of the largest representatives of this order in all of Europe. With a body length of 14 to 27 millimeters, the male of the South Russian tarantula usually remains smaller than the female. The leg span of the species can be up to 70 millimeters.

Frontal view of a female with the head area and eyes clearly visible

The carapace (back plate of the prosoma or front body) is colored olive brown. Its front part has an indistinct band drawing. As is usual with wolf spiders, the eight eyes of the South Russian tarantulas consist of the two large main eyes and the six smaller secondary eyes. The latter are probably used to perceive light, while the main eyes are used for the actual sense of sight. As usual for spiders of the superfamily Lycosoidea , the eyes are arranged in two rows one above the other, each comprising four eyes. The front row is slightly curved. The distance between the lower central and side eyes is smaller than that of the lower central eyes. The lower median eyes are larger than the lower lateral ones. The latter are also framed by a black ring. The distance between the rear median eyes or the main eyes is smaller than their own diameter. The distance between the upper side eyes is significantly larger than that between the lower side eyes. The cephale (towards the head) region of the fovea (apodem) is higher than the thoracic ( towards the chest). The fovea also has a confluent (confluent) angle and a star-shaped, light gray-white spot. Open strips emerge from the area of ​​the fovea. On the carapace there is also a light, narrow and blurred median band that has two elongated dark spots. The carapace is also adorned by several narrow, white-gray side stripes that are quite numerous and scattered and can be colored black or formed as small spots.

Another frontal view of a female, here with the clearly visible chelicerae .

The chelicerae (jaw claws) are robustly built and have a strong base. The apical (at the tip) segment, the actual and needle-shaped claw of a chelicere rests on a groove in the basal segment, which is covered by setae ( hairs ) of various properties. The claw becomes narrower and narrower from the bottom and ends in a fairly sharp end. The pore from which the venom is expelled is located on the subterminal (at the bottom end) section of the claw. In the longitudinal direction, parallel grooves run on the catching surface and form a comb-like structure, which in turn forms a blade-like structure. On both sides of the muzzle grooves there is also a row of four cone-like teeth. The basal areas of the chelicerae are colored yellow or orange-brown. They are also very hairy. The sternum (breast plate of the prosoma) appears completely black.

Lateral view of a female with clearly visible leg curls

The legs are strong and thick and grayish olive-brown in color. They are also spotted or curled and hairy. This is especially true of the femora (splints), which are colored yellow-ocher ventrally and laterally. Dorsally (above) the legs are provided with spikes. The trochanters ( thigh rings ) are colored black on the ventral side (underside), although the trochanters can also be completely black. They can also have a yellow hue on the ventral side. As with the chelicerae, the basal sections of the pedipalps (transformed extremities in the head area) have a yellow or orange-brown color.

Dorsal view of a female with the clearly visible drawing elements on the carapace and the opisthosoma

The opisthosoma (abdomen) has a dark olive-brown basic color. It has a lancet-shaped spot in the middle that is strong black. This is flanked by round or star-shaped white dots. These are followed by six pairs of small white spots and angular spots. The flanks of the opisthosoma are also provided with small white dots. The ventral side of the opisthosoma is black like the sternum in adult spiders and yellow in young animals. The striking and high-contrast colorations on the legs, the sternum and the ventral side of the opisthosoma serve as the threatening gesture that the spider takes in the event of an encounter with a possible predator (predator).

Genital morphological features

Frontal view of a male with the easily visible bulbi

As usual for the genus, the bulbi (male genital organs) each have a tegular (rear) apophysis ( chitinized process), which narrows towards its end and is shaped like a blade . At its end, however, it does not form a point, but appears to be cut off. The tegulum (middle sclerite or hard part of a globe) has chitinized and rib-like elevations. At the endapophysis of the finger-shaped conductor the tip occasionally has a small and sharp process. The cymbiii (last sclerite of the bulbi) and the tibia of the pedipalps are abundantly hairy.

Anterior view of a deceased female. This is also where the epigyne is located .

The epigyne (female sex organ) is also almost completely covered by thick hair. It consists of a chitin plate that is wider than it is high and has a red color. The epigenynous pit is completely covered by an ovoid-convex chitinous formation. It is divided by a mirror-inverted T-shaped septum (partition) with a short and wide stem. The transverse (transverse) basal (forming the base) part is wide and large, while the apical (at the top) has a chitinized edge. The spermatheks (seed bags) are small and rounded. Basal they have egg and diverticulum-shaped structures.

Similar species

Female of Geolycosa vultuosa at the exit of its living tube

Confusion of the South Russian tarantula with other spiders is comparatively unlikely due to its considerable size. A very similar species is Geolycosa vultuosa , which also belongs to the wolf spiders (Lycosidae) , whose distribution area extends from Southeast Europe to Central Asia and thus overlaps extensively with that of the South Russian tarantula. Both species are characterized by a similar way of life and in the event of a threat they show distinctive threatening gestures . G. vultuosa can be identified from the South Russian tarantula , apart from its smaller body size, which is no more than 24 millimeters in the female, due to the ventrally yellow-orange colored patellae and the ventral-proximal (proximal = located to the center of the body) and distal black colored tibiae distinguish. Both species prefer flat habitats, whereby G. vultuosa also inhabits meadows in the hill country, smaller elevations and also larger cities. In addition, G. vultuosa needs a slightly higher air humidity and, in contrast to the South Russian tarantula, tends to form colonies.

Female of the closely related Apulian tarantula ( Lycosa tarantula )

It can also be confused with other species of the Lycosa genus , for example the Apulian tarantula ( L. tarantula ), which is widespread in the Mediterranean region . Apart from its smaller final size (max. 30 millimeters in the female of the species) and the genital morphological features, the South Russian tarantula can also be distinguished from this by its color. The basic color of the Apulian tarantula is more yellowish or orange in the female and white-gray in the male. The carapace of the Apulian tarantula has a lighter longitudinal band in the center and another on each side on the flanks. These are in turn flanked by another dark band on the inside. On the opisthosoma of the Apulian tarantula there is a dorsal longitudinal spot that merges into two spikes on both sides, where dark angular spots open. The Apulian tarantula also has warning colors that are presented in the event of danger. In this species, they consist of a black transverse band and the orange color around it. For the same purpose, the legs of the Apulian tarantula are curled black and white ventrally, but dorsally colored quite uniformly gray.

Female of the black-bellied tarantula ( Hogna radiata )

There is also a possibility of confusion with the black-bellied tarantula ( Hogna radiata ), which is also found in the Mediterranean area , but with a maximum body length of 25 millimeters in females, it usually remains significantly smaller than the southern Russian tarantula. It also belongs to the family of wolf spiders. In addition, the black-bellied tarantula is markedly less contrasting. Your carapace is dorsally colored light brown and has two black longitudinal bands, which in turn have light radial stripes. The opisthosoma has a darker lancet spot and also angular spots, which are, however, much more indistinct than in the South Russian tarantula. For the threatening gesture, the ventral side of the black-bellied tarantula is completely black. The common name of the species comes from this property.

toxicology

The Toxicology (toxicology) deals with the composition of toxins. The venom of the South Russian tarantula contains 0.659 milligrams of protein per milligram of spider venom. These include high molecular weight proteins, the molecular masses of which are mainly distributed in the range from 14 to 31  kilodaltons . The broadest bands, which make up around 80% of the poison's proteins, are around 14 and 20 kilodaltons, respectively.

With the help of the MALDI-TOF analysis, the molar mass distribution of the proteins between 1 and 10 kilodaltons could be determined. The peptides recorded in this way can be divided into three groups. The first group contains peptides with a molecular weight of about 2 to 2.5 kilodaltons, i.e. about 20 amino acids. From cDNA analyzes it can be seen that no cysteine ​​can be found in these proteins. This also applies to the linear lycoticins 1 and 2 with molecular masses of 1960.49 and 1988.86 Dalton, respectively. Both peptides have a similar sequence , only the second amino acid differs ( lysine and arginine ). While the range between 2 and 2.5 kilodaltons has an above-average number of proteins, the weight range from 3 to 5 kilodaltons is hardly represented in the poison of the South Russian tarantula. However, there is another lycoticin, lycoticin 3, at 3149.75 daltons. The second group identified mainly comprises peptides with molecular weights in the range from 4.8 to 5.5 kilodaltons. They therefore consist of about 50 amino acid residues and contain four or five disulfide bridges . The third group consists of peptides in a mass range of 7 to 8 kilodaltons, i.e. more than 60 amino acid units and with more than 5 disulfide bridges. The poison of the South Russian tarantula differs from that of many other spiders in that it has comparatively few peptides with molecular weights between three and five daltons. In the case of poisons from other spiders, peptides in this mass range form the main component of their poisons. However, the lycoticin 3 has a structural relationship to the lycotoxin II of the Lycosa carolinensis .

Analyzes of cDNA libraries from the venom glands of the South Russian tarantula show that the venom has more than 200 toxin-like peptide or amino acid sequences.

Pharmacological characterization of the poison

The pharmacology deals with the interaction between materials and living organisms. When laboratory mice were administered an amount of 200 µg toxins per milliliter in experiments, the electrically stimulated contraction of the diaphragmatic preparation of the phrenic nerve (located in the diaphragm) of the mice could not be blocked. In further experiments with rats, the poison showed little effect on the twitching reaction of their vas deferens. Even a concentration of 200 µg per milliliter of poison administered to rats only resulted in a partial inhibition of the twitching reaction of the test animals lasting 20 minutes. The situation was different in the case of mice and rats, to which the poison of the tarantula species Ornithoctonus huwena was administered in the same concentration. The result here was that the twitching response of the nerve diaphragmatic preparation of the mice or the vas deferens of the rats were blocked much faster. The test animals were identical to those given the poison of the South Russian tarantula. Much more meaningful results were obtained from experiments with toads injected with poison from the South Russian tarantula. Here the poison exerted a great influence on the muscle contraction taking place in the hearts of the toads , or with an administration of 100 µg toxins per milliliter of the spider venom the rate and strength of the heartbeat of the toads were greatly increased. It is therefore assumed that the poison of the South Russian tarantula contains cardiotonic (affecting the heartbeat) components.

Currently, cardiotonic agents are classified into three classes based on their subcellular mechanisms of action. These are agents that have an effect via upstream mechanisms (calcium mobilizers) as well as central and downstream mechanisms (calcium sensitizers ). These agents induce a positive inotropic effect by increasing the intracellular calcium and the calcium ion concentration. The hemolytic activity (dissolution of red blood cells or erythrocytes ) of the spider venom could be confirmed by using fresh human erythrocytes. For this purpose, the mean effective concentration (EC 50 ) of peptides must be 1.25 milligrams per milliliter of poison.

It has been known since 2004 that the poison of the South Russian tarantula contains antimicrobial peptides (effective against bacterial pathogens), the so-called lycocitins 1, 2 and 3, which can therefore inhibit the growth of gram-positive and gram-negative bacteria and fungi in micromolar concentrations. In 2009 it was also found in tests devoted to this topic that these peptides affect the cell strains and are most susceptible to it. This particularly affects Bacillus subtilis (hay bacillus) and various staphylococci ( Staphylococcus ), in which growth was strongly inhibited when three milligrams of peptides were added for each milliliter of poison administered. In addition, the poison was effective against Corynebacterium glutamicum and Micrococcus luteus , but weakly against the yeast Candida albicans . In contrast to this, even at a high concentration of 12 milligrams of peptides per milliliter of poison administered, the poison has no detectable effect on the bacteria Escherichia coli (Colibacterium) and baker's yeast ( Saccaromyces cerevisae ).

In the past, many antimicrobial peptides have been identified from spider venom, including lycotoxins I and II from the species Hogna carolinensis , which, like the South Russian tarantula, also belongs to the wolf spider family. Both toxins are linear antimicrobial peptides that have an amphipathic α-helix structure typical of pore-forming peptides . Their pore formation mechanism was further confirmed by their stimulating outflow of calcium ions from synaptosomes (structures isolated from neurons or nerve cells). A similar effect achieve the Cupiennine from the venom of the Fischer Spider counting (Trechaleidae) Great wandering spider ( Cupiennus salei ) and in the venom of the family of lynx spider counting (Oxyopidae) Type Oxyopes kitabensis Oxyopinine contained. Seven new short linear antimicrobial and cytolytic (cell-dissolving) peptides, so-called latarcins, were discovered from the venom of the spider species Lachesana tarabaevi , which belongs to the family of the ant hunters (Zodariidae). Five new peptides, which are very structurally similar to the latarcins analyzed, could also be predicted for the venomous gland of the species using Expressed Sequence Tags (short DNA sequences).

These spider venom peptides are linear, cationic (containing the positively charged cations), α-helical and antimicrobial peptides. What these antimicrobial peptides have in common are the inhibition of microbial growth at low micromolar concentrations and the formation of an amphipathic (both water-loving as well as lipophilic , i.e. soluble in oils and fats) and cationic helical (spiral-shaped) formation in hydrophobic or water-repellent environments. A large number of antimicrobial peptides, including linear cationic α-helical antimicrobial peptides, have now been discovered in both animals and plants. These peptides, mostly consisting of 12 to 45 amino acids, play an important role in the innate immune system of most living organisms. The majority of them can kill microorganisms with the following four characteristics:

  • Selective toxicity
  • Rapid kill
  • Broad antimicrobial spectra
  • No development of resistance

Structure of the poison glands

The general structure of the venom glands of the South Russian tarantula corresponds to that of other spiders. The two paired glands are located in the dorsal front part of the prosoma and are connected to the chelicerae by tube-like channels. Each of the two glands has a channel. The poison glands are similar in size and have an elongated and sack-shaped shape. Their length is about four millimeters, with which they extend from the central area of ​​the prosoma to the basal area of ​​the chelicerae. The distal part of a single venom gland is wider than the proximal part and there is a large lumen (cavity) in the middle . The poison glands are surrounded by a thick layer of muscle, the bundles of which are irregular and clearly recognizable. These muscle bundles cover the glands in a spiral formation and end in the first part of the venomous ducts. They allow the discharge of poison and thus the use of the chelicerae by the spider.

Occurrence

Well camouflaged male on an artificial stone surface, found in the Moldovan city ​​of Bălți .

The distribution area of ​​the South Russian tarantula extends largely over the Eurasian steppe . It therefore begins in western Central Europe , where the species has been identified in Austria , the Czech Republic , Slovakia , Hungary and Slovenia . In Eastern Europe , the spider has been shown to be found in Ukraine , Belarus, and the central, southern and eastern European parts of Russia . In Southeastern Europe , finds of the South Russian tarantula have so far been recorded in the states of Bosnia and Herzegovina , Serbia , Bulgaria , Romania and the Republic of Moldova .

Following the course of the steppe, the South Russian tarantula is also found in the Asian part of Turkey and in the Caucasus , although no evidence is available from Armenia . The species is also present in the parts of Central Asia , Iran and China , through which the Eurasian steppe runs. Their occurrence ends east in Korea .

Habitats

Sandy, open steppe areas with little vegetation, such as the banks of the Ochsenbrunnlacke in the Fertő / Neusiedler See cultural landscape ( Burgenland in Austria ), are inhabited by the South Russian tarantula.

As a steppe species, the South Russian tarantula lives in thinly overgrown, sandy areas with little vegetation and prefers those with salty soils. There are also sightings of the species from agricultural areas.

By contrast , forests are completely avoided by the South Russian tarantula . The same applies to otherwise suitable areas with too much gravel in the substrate. Areas with a decreasing salt content or where there is a marked increase in vegetation are less populated.

Spread in Central Europe and today's occurrence in Austria, protective measures

Females at the Sechsmahdlacke near the market town of Apetlon in the Neusiedl am See district ( Burgenland , Austria ) .

The first record of the South Russian tarantula in Central Europe was made in 1888. Since then, the species spread to the northwest until the 1940s, especially in the river regions. Since then, however, there has been a significant decline in the species in these areas, which continues to this day. For example, in the area of ​​the former Czechoslovakia in 1992 only two sites were documented. However, at least in today's Czech Republic, the overall situation has improved. The reason for the decline of the species in Central Europe is the straightening of rivers and the shrinking of suitable biotopes on the banks.

The South Russian tarantula occurs in Seewinkel in the Austrian Burgenland , whereby the area is also its occupied western limit of distribution. According to reports, however, the species was also found further west in Marchfeld in Lower Austria , in Bad Vöslau and in Tullnerfeld . Their occurrence is said to extend as far as Krems an der Donau . In Vienna there are finds from warmer locations on the Simmeringer Haide and on the Laaer Berg .

The occurrence of the species at Seewinkel is determined by two different habitats. These are located on the one hand on the banks of the salt lakes in these areas , which have a high salt content. In addition, the species occurs on grazed dry grassland . Because of its importance and the attention it draws to the spider fauna, it is considered a flagship species in the Seewinkel.

When hostage plate , the Kirch and the one pictured here Zicksee in Illmitz , the main distribution area of the South Russian tarantula is in the Seewinkel.

The main area of ​​distribution in the Seewinkel is on Geiselteller , Zicksee and Kirchsee. These biotopes, located in the market town of Illmitz , are part of the Fertő / Neusiedler See cultural landscape and are characterized by a large number of arid, steppe and salt areas. Due to the relatively low level of human intervention in these habitats and the given protection status, the find rate of the South Russian tarantula is high there.

Sand area surrounded by plants of the European samphire ( Salicornia europaea ) near the Legerilacke in the north of Podersdorf am See .

Another area of ​​distribution is near the Legerilacke north of Podersdorf am See , which has the densest occurrence. This is distributed over three colonies, which are further away from the other occurrences of the South Russian tarantula in Seewinkel. The areas inhabited by the spider there, which consist of areas overgrown with sod , are surrounded by dense stands of reeds and types of ostrich grass . The use of reed cutting machines and the lack of protection status in general are problems for the stocks of the South Russian tarantula at this location.

At the Große Neubruchlacke , the Ochsenbrunnlacke and the pear tree lacquers shown here in the center of the Seewinkel, the South Russian tarantula is becoming increasingly rare.

The third distribution focus is in the center of the Seewinkel, surrounded by the pear tree lacquer , the Ochsenbrunn lacquer and the large Neubruch lacquer . The pear tree varnishes and the Ochsenbrunn varnishes were once the salt varnishes in the Seewinkel with the highest salt content. In particular in the pear tree lacquer, however, a reduction in the salt content on its banks can be determined due to a dam built in the water body in the 1970s. The groundwater situation in the center of the Seewinkel generally favors the desalination of the salt lakes there. The Große Neubruchlacke is the only salt varnish located there that still has a high salt content. The growing areas of reeds and ostrich grasses, in addition to the already very high populations of the Neusiedlersee salt plumes ( Puccinellia peisonis ), are leading to dwindling populations of various ground beetles and other arthropods, including the South Russian tarantula. These relationships indicate that, as with other salt lakes in the Seewinkel, the salt concentration in the water in the Große Neubruchlacke is decreasing. The already small populations of the southern Russian tarantula in the eastern salt lakes are continuing to decline and a permanent disappearance of the species in this area cannot be ruled out. The occurrence of the South Russian tarantula is only ensured here by the agricultural management of these habitats by human hands. The meadows on the banks of the Birnbaumlacke and Ochsenbrunnlacke are mowed in spring, while grazing takes place on the Große Neubruchlacke.

Previous finds at the Albersee , southwest of the pear tree lacquers , at the Upper Stinkersee and at the Xixsee could not be confirmed in retrospect. This may be due to the fact that in these waters no habitats suitable for the species have declined due to human influence. In addition, some of the salt lakes have now completely disappeared and with them probably populations of the South Russian tarantula. Exact analyzes of the establishment of the species in Seewinkel are not possible due to a lack of knowledge about the spreading behavior of the South Russian tarantula. In addition, individuals and young animals immigrated from other areas were often seen. Moving closer to the bank area of ​​the salt lakes is also unfavorable, as the spiders' hiding places can be flooded by the passage of water.

As a protective measure of the species in the Seewinkel, in addition to the expansion of protection zones in suitable habitats, grazing and the pushing back of massive stocks of reeds and ostrich grasses are recommended.

Way of life

Females at the exit of their living tube during the day

The way of life of the South Russian tarantula corresponds to that of other species of the genus Lycosa and thus resembles that of the closely related Apulian tarantula ( L. tarantula ). Like them, the South Russian tarantula digs burrows that serve as the nocturnal spider's abode during the day and are rarely abandoned during this time. If the spider is out and about during the day, which is seldom the case with adult spiders, it retreats back to its shelter even if it is slightly jarred. In spring, however, the species can increasingly be found during the day at the exit of the tube mouth, where it then basks. At night she leaves the apartment and goes in search of prey. Young animals stay outside their hiding places more often during the day.

The South Russian tarantula, like some other wolf spiders, is able to swim thanks to its thick hair pads, which give the spider hydrophobic (water-repellent) properties. It can also easily cross larger rivers. It has been found that the species can linger on the surface of the water for up to a week. It is also possible for the South Russian tarantula to stay in its living tube for a long time, even if it is flooded.

Tube construction

Housing tube of the South Russian tarantula

The self-dug and web- lined living tube of the South Russian tarantula can have a depth of up to 60 centimeters. Due to various obstacles in the ground such as stones and roots, the tube can have a curved course. In the area of ​​the opening, the diameter is a maximum of 3.5 centimeters. The mouth is designed like a collar, heavily woven with spider silk and provided with grasses and clods of earth.

The structure depends on both the stage of the spider and the season. Even the young ones dig living tubes, which are flatter due to the smaller size of the animals and have a smaller diameter (initially 8 to 12 millimeters). In autumn the young adult spiders build a living tube with a diameter of two and a depth of around 15 centimeters. Before wintering, the mouth is completely closed with soil. In addition, the tube is deepened during this time. In the following spring, the earth tube is exposed again and partially renewed. During cold spells, however, it is also closed again, although the upper part then remains free, unlike when it was closed for winter storage. The diameter of the tube is 1.5 to 3.5 centimeters during this time. Pregnant females close the mouth again shortly before the cocoon is built , which in this case happens with a dome-like structure made of spider silk, earth particles and plant material. After the cocoon is made, it is opened again.

Hunting behavior and range of prey

Female outside of its living tube in search of prey

The South Russian tarantula hunts at night according to its time of activity, but prefers to hunt at dusk. Like most of the wolf spiders, this species also hunts without a spider web , but rather freely as a stalker . After leaving the shelter, the spider looks for places that are suitable for lurking prey. As usual with wolf spiders, these are perceived with the help of the well-developed eyes and, as soon as they come within range, jumped at directly, which can happen from a few centimeters away. A poison bite displaced by the chelicera renders the prey unable to escape or defend themselves.

The prey spectrum of the South Russian tarantulas is mainly composed of other arthropods , including many species of beetles that also live in steppes. Larger, well-fortified representatives of this order, such as various scarab beetles (Scarabaeidae) or tiger beetles (Cicindelinae) also regularly fall victim to the spider. In addition, locusts are one of the more common prey animals of the species. Furthermore, because of its large size for spiders, it is possible for the species to prey on smaller vertebrates . The catch of young sand lizards ( Lacerta agilis ) has already been documented.

Remnants of eaten prey, preferably the exoskeletons of the arthropods sucked out by the spider , are often found at the mouth of the tube and indicate a living tube used by an individual of the South Russian tarantula.

Life cycle and phenology

The life cycle is divided whose appearance is determined by the seasons, as in other spinning into several sections. The same applies to the activity time of the respective stages.

Courtship and mating

A male presumably in front of a female's living tube

The mating season of the species is in September and October. At this time, free-roaming males can often be found during the day, who seek shelter for females. Finding a female is presumably made possible for a male through pheromones (messenger substances) that are native to the species , which females willing to mate and which can be perceived by sexually mature males. Once a male has found the shelter of a female, it begins a courtship dance , as is usual with wolf spiders , while the female remains motionless in its living tube. The courtship behavior can have any duration.

If the female replies that the male is willing to mate, the actual mating takes place, which takes place in the female's living tube and takes place in the position typical of the superfamily of the Lycosoidea . The male rises frontally on top of the female so that both sexual partners are on top of each other. With the second and third pair of legs, the male grasps the carapace of the female and the actual mating begins, in which the male alternately inserts his bulbs into the epigyne of the female for sperm transfer. The pairing can last an hour or two before both partners separate.

Making cocoons and laying eggs

Illustration from Brockhaus-Efron (1890–1907), which shows a female of the South Russian tarantula with an egg cocoon .

While the male dies shortly after mating between November and December, the now fertilized female, which has stored the male's sperm in its spermatheque, hibernates. To do this, it completely closes the subsequently deepened residential tube and retreats to its bottom. From March or April, the tube is opened and renewed by the female. In May, the production of the egg cocoon begins , which also happens in the residential tube and for which purpose it is closed again, this time with the characteristic tube dome.

The cocoon is initially blue in color, which gradually turns into a whitish hue. In addition, the egg cocoon has a diameter of 8 to 12 millimeters, a weight of about six grams and it contains a total of about 300 eggs. After the cocoon is finished, the living tube is opened again. The egg sac then, after characteristic species of wolf spiders from the female to the spinnerets attached performed with it. It is usually kept in the tube and held up to the sun on sunny days. If the young spiders do not develop, the female will eat her egg cocoon. If it loses it, the female tries to find the cocoon again. The spider also accepts foreign egg cocoons or even objects that resemble a cocoon. A female can make up to two cocoons in a row.

Incubation and hatching

Females with young animals

In the period between June and July (in favorable weather conditions as early as May) and thus a period of 30 to 70 days after the cocoons have been made, the approximately 100 young hatch and also climb like the wolf spider on the opisthosoma of the mother, from which they then carry to let. The young animals form two layers one on top of the other. They stay there until all the nutrients in the former egg cocoon have been used up and they have completed their first molt. This takes up to four days and the mother does not eat any food during this time, but vehemently defends its offspring. Between the separation of the young from the first cocoon and the construction of the second, however, the spider devotes itself to eating again.

In the case of the second egg cocoon, hatching occurs after a shorter time (in captivity after two weeks). The hatching rate was also 60 under laboratory conditions. The same examinations also documented the death of the mother after the young animals were separated from their mother.

The young animals grow up

After the young animals have separated from their mother, they start to build their own living tubes after a while. In contrast to the adult animals, the growing individuals of the South Russian tarantulas are even less true to their location and colonize new habitats over long forays between July and September and always create new tubes. Overall, the living tubes of young animals can often be found in a high density of individuals. The distances between the tubes are rather small.

The pups grow as arthropods usual several molts approach and go through several feeding skins (molting stages of spiders). Damaged or lost limbs can also be regenerated during this phase. The spider stops feeding before molting. The moulting takes one to two days, the new exoskeleton then usually needs almost 30 minutes (maximum one hour) to harden. Two days after the molt has been completed, the spider returns to prey. In addition to the remains of prey that have already been consumed by the spider, the exoskeletons of the spider, stripped off after a molt, can be an indication of an inhabited tube of the South Russian tarantula.

Reaching sexual maturity and life expectancy

Deceased female

The young animals undergo the last moult between September and October, the so-called maturity moult, after which sexual maturity occurs. This happens at the same time as the start of the mating season and the life cycle repeats itself. The female has a lifespan of two years, the male only one year.

Systematics

The systematics in the field of biology deals with the taxonomic (systematic) classification as well as with the determination and with the nomenclature (discipline of scientific naming) of living things including the South Russian tarantula.

The species name singoriensis is a modification of the Latin noun Singoria that gleichbededeutend with the Dzungaria is, in the South Russian Tarantel occurs numerous.

Description history

The South Russian tarantula was classified in the genus Aranea in the year it was first described by the author Erich G. Laxmann in 1770, as was common for spiders at the time, and was given the name A. singoriensis . After that it received more taxonomic renaming and positioning by various authors. Already under Feliks Paweł Jarocki the species was classified under the name L. ucrainensis in the genus Lycosa in 1825 . Ludwig Koch first mentioned the South Russian tarantula in 1897 under the name L. singoriensis , which is still valid today. It has been the most common name for the species since 1956 and is still valid today.

Controversial class affiliation

The South Russian tarantula was increasingly subordinated to the genus Allohogna under the name Allohogna singoriensis , which is now considered a synonym, alongside the genus Lycosa . Even today, the exact affiliation is controversial, especially since the taxonomic status of both genera is also unclear. Since 1971 the genus Allohogna has been synonymous with the genus Lycosa . However, this synonymization has been questioned several times. In addition to the South Russian tarantula, the species Lycosa shansia , which shares all the similarities listed below with the South Russian tarantula, was previously declared to belong to the genus Allohogna .

In contrast to the other Lycosa species, the carapace of the South Russian tarantula and other species of the Allohogna genus considered to be subject to a more clearly marked descent in the chest area. In addition, there are no spinule-shaped setae on the tarsi, only a dense scopula (leg hair). The lower row of eyes is also slightly curved laterally upward in the remaining Lycosa species, but gradually pronounced in the South Russian tarantula. The distance between the upper and lower median eyes is 1.5 to 1.7, in the other Lycosa species 2.5 to 2.9. The distance between the lower median eyes and the clypeus is in relation to each other in the South Russian Tarnatel 1.3 to 1.6, in the other representatives of the genus Lycosa, however, one to 1.2.

Essential distinguishing features are also found in the genital morphological features. The bulbi of the South Russian tarantula are characterized by the shape of the median abophysis, which resembles an elongated blade, and the protrusions on it (similar to the pseudo-tarantulas ( Alopecosa )). In addition, the origin of the emboli in both species is lateral-apical. The emboli here have blade-shaped lamellae. In most of the other species of the genus Lycosa , the median abophyses are shaped like a hook towards the rear. Similar to the South Russian tarantula, the emboli of these species have sharpened lamellae, but here the emboli arise in a completely apical position.

The other Lycosa species do not have side pockets on the Epigyne. It also lacks the anterior elevation in the epigyne that is typical of the other species. The septum of the South Russian tarantula can be clearly distinguished from those of the other species by its T-shaped alignment, which are longer than wide and usually fused with the epigynal groups. The sperm libraries of the other Lycosa species also have S-shaped sperm libraries with very long and thin tubes.

South Russian tarantula and human

Females in the mouth area of ​​its living tube, found in Bălți .

The South Russian tarantula has a different reputation among humans. It is sometimes said to be extremely dangerous for humans, as are other types of wolf spiders known as " tarantulas " (as well as tarantulas, which are also incorrectly called "tarantulas" ). Although the bite of the species can be associated with unpleasant complications for humans, the spider is nevertheless significantly less dangerous for humans than is often assumed.

Unlike the Apulian tarantula ( Lycosa tarantula ) or the black-bellied tarantula ( Hogna radiata ), the South Russian tarantula is hardly feared by the local population in its area of ​​distribution. There are even reports from Ukraine that children spend time with them.

Bite accidents and symptoms

Threatening female

Due to their size, including that of their chelicerae, the South Russian tarantula is able to bite humans. This happens especially with animals that are crowded in their living tubes. Otherwise the species is not considered aggressive. When threatened, the South Russian tarantula takes on the threatening gesture typical of some species of the superfamily of the Lycosoidea and also many tarantulas (Mygalomorphae) , in which the spider stands up, the front pairs of legs rise and the chelicerae spreads, with the signal colors on the extremities, the Chelicerae and come into their own on the ventral side of the spider's body.

The bite of the South Russian tarantula is considered painful, which also applies to the puncture itself, since its noticeability is increased by the teeth of the chelicerae. Another typical symptom is severe swelling and reddening of the bite wound, accompanied by pain in the same area that can last for 24 hours. Shortly afterwards, according to reports, the general condition of the bite victim deteriorates, which is seen as a result of the onset of apathy (lack of excitability) and need for sleep as well as the feeling of ankylosis (complete joint stiffness). One bite victim reported that after about an hour and forty-five minutes, he felt his entire body weight increased and, in addition to the need for sleep, there was also slight pain in the lower part of the chest and increased dyspnea (difficult breathing). The same patient felt these sensations disappear five hours after the bite. Only the local pain at the bite wound was still noticeable.

Terrariums

Male kept in a container

The species appears occasionally as a pet in the terrarium hobby . For keeping one or more specimens of the species (these must then be kept individually in order to prevent cannibalism ) the dry and warm climate of the natural range of the species should be simulated as well as possible. Dry sand, in which the spider can create living tubes, has proven to be a suitable substrate for keeping it. Offspring of the South Russian tarantula also exist in captivity, which simplifies keeping and does not threaten natural populations.

Hazard and protection

Housing tube of a South Russian tarantula in Ukraine . In the eastern part of its range, the species is not considered endangered, unlike in the western edge of it.

The degree of risk varies depending on the region. The global endangerment level of the species is not recorded by the IUCN . There are no threats to the population in the eastern part of the range.

In the Czech Republic , the South Russian tarantula is classified by the Czech Arachnological Society in the "Almost threatened" category. Of the species, which is still very rare there, 34 individuals have now been identified in 26 different areas. In neighboring Slovakia , the IUCN has classified the South Russian tarantula in category “E” (“Endangered”), which indicates that the species is more threatened in this country.

In particular, at the western outposts of their distribution area, there is a fight to preserve the declining populations of the species. In Austria, the South Russian tarantula is listed in category 1 (“critically endangered”) on the Red List of Threatened Species . For this reason it is subject to legal protection there.

See also

Individual evidence

  1. ↑ a b c d e f g h i j k l m n Lycosa singoriensis (Laxmann, 1770) from araneae - Spiders of Europe, accessed on October 25, 2020.
  2. ↑ a b c d e f g h i j k Z. H. Liu, W. Qian, J. Li, Y. Zhang: Biochemical and pharmacological study of venom of the wolf spider Lycosa singoriensis , Journal of Venomous Animals and Toxins including Tropical Diseases, Volume 15, Issue 1, 2009, pp. 79-92, ISSN 1678-9199, DOI: 10.1590 / S1678-91992009000100013, accessed on October 27, 2020.
  3. ^ Dietrich Kühlmann: Invertebrates of Europe: besides insects , observing and determining, Neumann, 1993, p. 272, ISBN 9783740200879 .
  4. ↑ 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, pp. 180-182, ISBN 978-3-440-14895-2 .
  5. ↑ a b c d Lycosa singoriensis (Laxmann, 1770) at the Donau-Auen National Park, accessed on October 25, 2020.
  6. ↑ a b c d e f g h i j k l m n o p q r s N. E. Fuhn & Niculescu-Burlacu: FAUNA REPUBLICII SOCIALISTE ROMÂNIA ARACHNIDA VOLUMUL V FASCICULA 3 F am.LYCOSIDAE , Academia Republicii Socialiste România, volume 5, edition 3, pp. 198-202.
  7. ↑ a b c N. Y. Kayhan, A. Bayram, T. Danisman, Z. Sancak: Morphological characterization of the venom apparatus in the wolf spider Lycosa singoriensis (Laxmann, 1770) , Journal of Venomous Animals and Toxins including Tropical Diseases, Volume 15, Issue 1, 2009, pp. 146-156, ISSN 1678-9199, DOI: 10.1590 / S1678-91992009000100013, accessed on October 27, 2020.
  8. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae N. Milasowszky & KP Zulka: Distribution and habitat types of the South Russian tarantula Lycosa singoriensis (Laxmann 1770 ), in Seewinkel: Data bases for effective target species management , BFB report 85, Biological Station Neusiedler See, Biological Research Institute Burgenland, 1996, pp. 1–36, ISSN 0257-3105, accessed on October 25, 2020.
  9. ↑ Geolycosa vultuosa (CL Koch, 1838) at the Wiki der Arachnologische Gesellschaft e. V., accessed on October 28, 2020.
  10. ↑ a b c B. A. Budnik, JV Olsen, TA Egorov, VE Anisimova, TG Galkina: De novo sequencing of antimicrobial peptides isolated from the venom glands of the wolf spider Lycosa singoriensis . In: Journal of Mass Spectrometry . tape 39 , no. 2 , February 2004, ISSN  1076-5174 , p. 193-201 , doi : 10.1002 / jms.577 .
  11. ↑ Lizhen Yan, Michael E. Adams: Lycotoxins, Antimicrobial Peptides from Venom of the Wolf Spider Lycosa carolinensis . In: Journal of Biological Chemistry . tape 273 , no. 4 , January 23, 1998, ISSN  0021-9258 , p. 2059-2066 , doi : 10.1074 / jbc.273.4.2059 , PMID 9442044 .
  12. ↑ a b Lycosa singoriensis (Laxmann, 1770) at the Czech Arachnological Society, accessed on October 26, 2020.
  13. ↑ Christian Komposch: Puszztazwerge and steppe wolves - the spider fauna of the Pannonian grasslands. pp. 209-218. - In: WIESBAUER, H. (Red.): The steppe is alive. Rock steppes and dry grasslands in Lower Austria, St. Pölten , the steppe is alive. Rock steppes and dry grasslands in Lower Austria, St. Pölten, pp. 209-218, accessed on October 28, 2020.
  14. ↑ a b c d e f g h i j Zoologie Romania: Lycosa singoriensis sau Tarantula romaneasca (Romanian) by Isohob Gabriel Alin, accessed on October 26, 2020.
  15. ↑ Lycosidae (Sundevall, 1833) at the Wiki der Arachnologische Gesellschaft e. V., accessed on October 26, 2020.
  16. ↑ a b c d e f g h i M. Prisecaru, IG Alin & T. Cristea: OBSERVATIONS REGARDING THE GROWTH IN CAPTIVITY OF WOLF-SPIDER SPECIE LYCOSA SINGORIENSIS (LAXMANN, 1770) , Studii și Cercetări, University of Bacău, volume 19, 2010, pp. 33-38, accessed October 27, 2020.
  17. ↑ Erich G. Laxmann: NOVAE INSECTORUM SPECIES , Novi Commentarii Academiae Scientiarum Imperialis Petropolitanae, Volume 14, p. 602.
  18. ↑ Lycosa singoriensis (Laxmann, 1770) in the World Spider Catalog , accessed on October 29, 2020.
  19. ↑ Lycosa (Latreille, 1804) in the World Spider Catalog , accessed October 29, 2020.
  20. ↑ a b c d e Dmitri Logunov: ON NEW CENTRAL ASIAN GENUS AND SPECIES OF WOLF SPIDERS (ARANEAE: LYCOSIDAE) EXHIBITING A PRONOUNCED SEXUAL SIZE DIMORPHISM , Proceedings of the Zoological Institute RAS, Volume 314, Issue 3, 2010, p. 233– 263, accessed October 29, 2020.
  21. ↑ Lycosa shansia (Hogg, 1912) in the World Spider Catalog , accessed on 29 October 2020th
  22. ↑ Lycosa singoriensis (Laxmann, 1770) at My Home Nature, accessed on October 27, 2020.
  23. ↑ Lycosa singoriensis (Laxmann, 1770) at Global Biodiversity Information Facility , accessed on October 27, 2020.
  24. ↑ Lycosa singoriensis (Laxmann, 1770) at the Wiki der Arachnologische Gesellschaft e. V., accessed on October 27, 2020.
  25. ↑ Lycosa singoriensis (Laxmann, 1770) at the Natural History Museum Vienna , accessed on October 27, 2020.

literature

Web links

Commons : South Russian tarantula  - collection of pictures, videos and audio files
This article was added to the list of excellent articles on November 20, 2020 in this version .