Poecilotheria fasciata
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Exhibited female of Poecilotheria fasciata |
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| Scientific name | ||||||||||||
| Poecilotheria fasciata | ||||||||||||
| ( Latreille , 1804) |
Poecilotheria fasciata lives in the tropical, evergreen dry forests in northern Sri Lanka . It is the longest known and first described species of the tarantula genus Poecilotheria . This species is locally called, like some other species, "Divimakulawa" or "Diamakulu". Poecilotheria fasciata wasimportedto Europe as early as the 17th century , but was notscientifically describedby Pierre André Latreille until 1804. The type epithet "fasciata" comes from Latin and means "banded" or "striped". It probably refers to the numerous black stripes and the black and white ribbons on the legs, which are part of the typical drawing of the animals.
distribution and habitat
Poecilotheria fasciata is native to the tropical, evergreen dry forests of the northern half of Sri Lanka, which in many places have been degraded by anthropogenic influences to tree-rich savannas with fields in between. In addition to the habitats mentioned, Krehenwinkel et al. also an occurrence in the thorn forests in the far north of Sri Lanka in the occupied area of the " Liberation Tigers of Tamil Eelam ", a paramilitary organization that makes it impossible to examine the area for further occurrences. Poecilotheria fasciata lives in Sri Lanka mainly in the lowlands and occurs from the coast up to altitudes of approx. 500 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 between 900 and 1600 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. The thorn forests consist of large stocks of low-growing, mostly strongly thorny bushes and isolated trees such as acacias . The trees in these forests only reach a maximum height of 9 m. This habitat is characterized by long dry seasons and also experiences larger temperature fluctuations during the day with locally up to over 40 ° C.
Their habitat does not overlap with any other Poecilotheria species. Despite the progressive degradation of the dry forests, Poecilotheria fasciata is not threatened with extinction, as it quickly establishes itself in the changed habitats due to its high adaptability ( cultural successors ). It also has the largest range of all Poecilotheria species in Sri Lanka.
features
size
The females reach a body size (approach of the bite claws to the spinnerets) of up to 7 cm. The males remain significantly smaller with a body size of 3–4 cm and are built in proportion much more delicate and long-legged than the females ( sexual dimorphism ).
No size information is available for the holotypes used by Latreille. Detailed information on the size of Poecilotheria fasciata can only be found in the literature from Ferdinand Karsch , who only describes a very small female in more detail.
drawing
The dorsal drawing on the carapace and the extremities is very similar to that of Poecilotheria vittata , although adult females of this species are said to be darker in color than the adults of Poecilotheria fasciata . 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 significantly from that of the Poecilotheria vittata mentioned at the beginning and is sometimes the only really certain distinguishing feature between the two species. In contrast to Poecilotheria vittata , Poecilotheria fasciata has a black and yellow mark ( warning color ) under the treads I and II. 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 always completely absent in Poecilotheria fasciata .
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 nymphs of Poecilotheria fasciata are considered to be very " social " because they live together for a long time in their mother's nest.
Reproduction
Krehenwinkel et al. suspect that the matings take place during the evening hours of the rainy season. This not infrequently ends in cannibalism by the larger female. Only at the beginning of the rainy season do the females build their cocoons with clutches, which are among the largest of the genus and contain up to 250 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. The young nymphs leave the mother's nest very late, so that sometimes two generations of the offspring can be in the same nest. Despite this pronounced “sociality” already mentioned, cannibalism on the part of the nymphs of the not so far developed larvae siblings often occurs immediately after the larvae have molted into the nymph stage.
Systematics
It was first described in 1804 by the entomologist Pierre André Latreille, although the species had been known in Europe for much longer. Latreille originally described the species as Mygale fasciata . The today no longer legitimate genus Mygale represented a kind of collective genus for tarantulas in Latreille's time. In 1851 the German arachnologist Carl L. Koch recognized the need for a new genus for Mygale fasciata and put it together with the tarantula known today as Acanthoscurria geniculata in the supposedly new genus Scurria , whereby the new species name was Scurria fasciata ( Latreille , 1804). However, the genus name Scurria had already been assigned to the snail genus Scurria in the family Lottiidae in 1847 by the British zoologist John E. Gray , which resulted in a conflict between the two genera according to the nomenclature rules . In accordance with the need for a new genus name for Scurria fasciata , it was in 1885 the French arachnologist Eugène L. Simon who established the genus Poecilotheria with its only species to date, Poecilotheria fasciata ( Latreille , 1804).
Due to the morphological similarities of the ventral drawing of the treads, a relationship between Poecilotheria fasciata and the South Indian Poecilotheria hanumavilasumica can be assumed. A relationship with Poecilotheria vittata also seems likely due to the very similar ecological demands, the dorsal pattern and the similar structure of the stridulation organs .
Terrarium keeping
Because of their beautiful appearance, the animals are increasingly kept and bred in terrariums. Krehenwinkel et al. recommend keeping 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. Despite good feeding, cannibalism is more common on the part of the much larger female. To encourage the construction of a cocoon, a dry season can be simulated, which slowly turns into a rainy season. The nymphs can often be kept in small groups in their first year of life without cannibalism failures. Adequate feeding is, however, essential.
Web links
Poecilotheria fasciata in the World Spider Catalog
- German Arachnological Society V. (DeArGe) - German association that promotes arachnology and takes care of the transmission of information in this field (publication organ : ARACHNE - ISSN 1613-2688 )
- Tarantula e. V. - German association that wants to expand and deepen arachnology and the general level of knowledge and knowledge exchange in this field.
literature
- H. Krehenwinkel, T. Maerklin, T. Kroes: Ornamental tarantulas - The genus Poecilotheria. Herpeton, Offenbach 2008, ISBN 978-3-936180-27-5 .
- P. Klaas: tarantulas. Verlag Eugen Ulmer, Stuttgart 2013, ISBN 978-3-8001-7881-0 .
- G. Schmidt: The tarantulas. Verlag KG Wolf, 2003, ISBN 3-89432-899-1 .
Individual evidence
- ↑ a b c d e f g h i j k l m n o H. Krehenwinkel, T. Maerklin, T. Kroes: Ornamentvogelspinnen - The genus Poecilotheria. Herpeton, Offenbach 2008, ISBN 978-3-936180-27-5 , pp. 45-47, 59-78, 104-109.
- ↑ P. Klaas: tarantulas. Ulmer, Stuttgart 2003, ISBN 3-8001-3696-1 , pp. 103-109.
- ↑ F. Karsch: Arachniden von Ceylon and von Minikoy collected by the doctors Poecilotheria and F. Sarasin. In: Berlin Entomological Journal. Volume 36, Issue 2, 1892, p. 274.
- ^ Poecilotheria A. Latreille: Histoire naturelle générale et particulière des crustacés et insectes. Published by F. Dufart, Paris 1804, p. 160.
- ↑ CL Koch: Overview of the arachnid system. Publisher by JL Lotzbeck, Nuremberg 1850, issue 5, p. 74.
- ^ EL Simon: Matériaux pour servir à la faune arachnologiques de l'Asie méridionale. I. Arachnides recueillis à Wagra-Karoor près Gundacul, district de Bellary par MM Chaper. II. Arachnides recueillis à Ramnad, district de Madura par M. l'abbé Fabre. In: Bulletin de la Société Zoologique de France. Vol. 10, 1885, p. 38.