Poecilotheria vittata

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Poecilotheria vittata
Poecilotheria vittata

Poecilotheria vittata

Systematics
Order : Spiders (Araneae)
Subordination : Tarantulas (Mygalomorphae)
Family : Tarantulas (Theraphosidae)
Subfamily : Poecilotheriinae
Genre : Poecilotheria
Type : Poecilotheria vittata
Scientific name
Poecilotheria vittata
Pocock , 1895

Poecilotheria vittata ( Syn. : Poecilotheria pederseni ) inhabits the tropical evergreen dry forests in the south of Sri Lanka and is one of the tarantulas genus Poecilotheria . The species is locally called, like some other species, "Divimakulawa" or "Diamakulu". The type epithet "vittata" comes from Latin and means "banded". It probably refers to the numerous black and white bands on the legs, which are part of the typical drawing of the animals.

distribution and habitat

Poecilotheria vittata is native to the tropical, evergreen dry forests in the southeast of Sri Lanka, which in many places have been degraded to tree-rich savannahs due to anthropogenic influences. Gabriel et al. also indicate the region around Galle in the south of Sri Lanka as a natural range. Poecilotheria vittata lives in Sri Lanka mainly in the lowlands and occurs from the coast up to altitudes of approx. 100 m. The distribution area is characterized by a tropical, Bixerian climate (one rainy season in summer and one in winter) with only minor temperature fluctuations. The annual average temperature is around 28 ° C while the annual precipitation is only around 1000 mm. Despite the two rainy seasons a year, the climate can be described as rather dry due to the consistently high temperatures and low rainfall.

The trees in the sometimes very dense evergreen dry forests form considerable forests up to 20 m high in places. In regions with degraded vegetation there are tree savannas with groups of trees of different sizes and evergreen scrubland. In small groups of trees, each tree can be inhabited by one or more tarantulas.

Their habitat overlaps if the information on the distribution of Poecilotheria vittata by Gabriel et al. agree, in the southwest only with Poecilotheria ornata . Despite the progressive degradation of the dry forests, Poecilotheria vittata is not threatened with extinction, as it quickly establishes itself in the changed habitats due to its high adaptability ( cultural successors ) and z. B. with the Yala National Park has a more than 1500 km² large retreat.

features

size

The females reach a body size (approach of the bite claws to the spinnerets) of 6 to 7 cm. With a body size of approx. 4 cm, the males remain significantly smaller and are relatively more delicate and long-legged than the females ( sexual dimorphism ).

The holotype (male) described by Reginald I. Pocock in 1895 has a length of 34 mm. The carapace is 17 mm long and 15.2 mm wide. The leg I measures 72 mm, the leg II 63 mm, the leg III 57 mm and the leg IV 66 mm. The metatarsus of leg I is 17.8 mm and that of leg IV is 17 mm long. In addition, the tibia of running bone IV measures 15 mm.

Since the holotype is only a male, the size specifications of the female holotype described by Peter J. Kirk in 2001 for Poecilotheria pederseni Kirk , 2011, a recognized synonym for Poecilotheria vittata , are listed below. The carapace is 24 mm long and 20 mm wide. The opisthosoma measures a length of 26 mm and a width of 16 mm. The chelicerae are 8 mm long. The eye hump is 1.7 mm long and 4 mm wide. The length of the legs is made up as follows:

  • Leg I: femur - 19 mm, patella - 10 mm - tibia - 16 mm, metatarsus - 17 mm, tarsus - 10 mm, total - 72 mm
  • Leg II: femur - 17 mm, patella - 9 mm - tibia - 18 mm, metatarsus - 14 mm, tarsus - 10 mm, total - 68 mm
  • Leg III: femur - 13 mm, patella - 7 mm - tibia - 11 mm, metatarsus - 16 mm, tarsus - 9 mm, total - 56 mm
  • Leg IV: femur - 16 mm, patella - 8 mm - tibia - 14 mm, metatarsus - 17 mm, tarsus - 9 mm, total - 64 mm

drawing

The dorsal drawing on the carapace and the extremities is very similar to that of Poecilotheria fasciata , whereby adult females of this species are said to be lighter in color than the adults of Poecilotheria vitatta . The coloration of the adult females is made up of high-contrast white and gray tones as well as black fields and lines. The central, white spot on the carapace is bordered by two black longitudinal stripes that converge on the eyelet to form a so-called "mask". On the legs, grayish-white and black drawing elements alternate. The buttons, on the other hand, are usually drawn with less contrast. Males and nymphs are colored quite uniformly dark gray, whereby nymphs initially still have the typical, high-contrast pattern, which almost completely disappears in the mature males. From a body length of approx. 3 cm, females can be distinguished from males in nymphs.

The ventral side of the walking legs of the adult animals differs clearly from that of the Poecilotheria fasciata mentioned at the beginning and is sometimes the only really sure distinguishing feature between the two species. In contrast to Poecilotheria fasciata , Poecilotheria vittata has no black and yellow markings ( warning color ) under the legs I and II, but only shows high-contrast black and white drawing elements. The wedge spot typical of Poecilotheria vittata on the underside of the femur of the leg IV can also be used as a further distinguishing feature, since this is absent in Poecilotheria fasciata . However, it should be noted that this characteristic is not completely stable within the species and can therefore be differently pronounced. So one finds z. For example, in some copies, instead of a wedge mark, a continuous black line that leads to the next black drawing element.

The spiders have a white or grayish, oak-leaf-like spot (folium) on the upper side of the opisthosoma , which is surrounded on both sides by a stripe pattern and is reminiscent of tiger stripes. A darker line usually runs lengthways in the middle of the foil. The underside is dark brown to black in color.

Way of life

The animals occur particularly in habitats with individual groups of trees (savannas) in sometimes very high population densities. The spiders usually hunt at night and are in their living tunnels during the day, where they can keep the temperature and humidity very stable and thus avoid the midday heat. They prey on tree-dwelling insects and reptiles that are close to their web. The young spiders move away from the mother and her siblings at a very young nymph stage (approx. 1.5 cm in height).

Reproduction

The mating takes place in the evening hours of the rainy season and is usually peaceful if the female is well fed. Only in the dry season do the females build cocoons, which often contain over 200 eggs. The so-called pre- larvae hatch from the eggs after about four weeks and are almost completely immobile due to their yolk-filled opisthosoma. A molt in a second pre-larval stage, as for example in Poecilotheria metallica , does not take place. After a further three weeks they reach the larval stage, in which they are fully able to move and, with the help of their mother, can leave the cocoon. However, the larvae do not yet ingest any external food. After about three weeks in the mother's nest, the larvae molt into completely independent nymphs. As already mentioned, the nest is usually left at an early nymph stage. The young nymphs do not show any increased cannibalism in the nest, as is the case e.g. B. is the case with Poecilotheria ornata .

Systematics

The first description of Poecilotheria vittata was in 1895 by Reginald I. Pocock on the basis of a single male. Since no collection data were available for the specimen, the distribution area for this taxon was unknown for a long time.

The holotype was later compared by Peter J. Kirk with female specimens of Poecilotheria striata Pocock , 1895, whereby, despite the missing yellow drawing elements, he found a match of the ventral drawing of the treads and synonymized the taxon with Poecilotheria striata Pocock , 1895 in 1996 .

In 2001, Kirk then described Poecilotheria pederseni based on a description of the ventral drawing of the legs III and IV. Gabriel et al. recognized in 2013 when the holotype of Poecilotheria vittata was re-examined that the holotype, just like Poecilotheria pederseni , has wedge marks on the underside of femora III and IV. These wedge marks were not recognized by Pocock and Kirk because the alcohol used for preservation had probably bleached the animals so much that the wedge marks outside of the alcohol were not visible due to the rapid drying of the material. It was only by viewing under UV light that these wedge stains could also be made visible outside the preservation vessel. Due to this knowledge and the non-existent warning coloration, the synonymization of Poecilotheria vittata with Poecilotheria striata became obsolete, as there are morphological differences between the two taxa. Since the investigation showed that there seem to be no morphological differences between Poecilotheria vittata and Poecilotheria pederseni , Poecilotheria pederseni was synonymous with Poecilotheria vittata according to the nomenclature rules , and Poecilotheria vitatta regained its species status.

Due to the similar dorsal drawing, the almost identical ecological demands and the similar structure of the stridulation organs , a close relationship between Poecilotheria vittata and the Poecilotheria fasciata found in northern Sri Lanka is very likely. Based on the similar ventral pattern of the hind legs, a closer relationship to Poecilotheria ornata would not be unthinkable.

Terrarium keeping

Because of their beautiful appearance, the animals are increasingly kept and bred in terrariums. It is recommended to keep them all year round at a daytime temperature of approx. 28 ° C and a relative humidity of approx. 70%. The dimensions of the terrarium for adult females should not be less than 20 × 30 × 40 (L × W × H). Well-nourished females can be mated at any time after molting for offspring. When breeding in the terrarium, make sure that it is not too moist after the cocoon has been built, otherwise the mother animal usually eats the cocoon. It is therefore advisable to imitate the dry season for breeding. The nymphs can be kept in smaller groups in the first year of life, although this does not correspond to the natural behavior of the young nymphs. Adequate feeding is, however, essential.

Web links

Commons : Poecilotheria vittata  - collection of images, videos and audio files

Poecilotheria vittata in the World Spider Catalog

literature

Individual evidence

  1. ↑ a b c d e f g h i j k l m n Krehenwinkel, H .; Maerklin, T .; Kroes, T .: Ornamental tarantulas - The genus Poecilotheria. Herpeton, Offenbach 2008, pp. 46-47, 59-78, 139-143, ISBN 3-936180-27-X
  2. ↑ Translation of vittata on www.engyes.com ( Link )
  3. ↑ a b c d e Gabriel, R .; Gallon, R .; Smith, A .: The revised taxonomic status of some Poecilotheria species Simon, 1885 (Araneae: Theraphosidae). British Tarantula Society Journal 28 (3), 2013, pp. 103-110
  4. ↑ a b Pocock, RI: On a new and natural grouping of some of the Oriental genera of Mygalomorphae, with descriptions of new genera and species. Annals and Magazine of Natural History, Series 6, Vol. 15, 1895, pp. 165-184
  5. ↑ Pocock, RI: The genus Poecilotheria: its habits, history and species. Annals and Magazine of Natural History, Series 7, Vol. 3, 1899, pp. 82-96
  6. ↑ a b Kirk, PJ: A new species of Poecilotheria (Araneae: Theraphosidae) from Sri Lanka. British Tarantula Society Journal 16 (3), 2013, pp. 77-88
  7. ↑ Kirk, PJ: A new species of Poecilotheria (Araneae: Theraphosidae) from Sri Lanka. British Tarantula Society Journal 12 (1), 1996, pp. 20-30