Nephila clavata
| Nephila clavata | ||||||||||||
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Nephila clavata , female and two males |
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| Scientific name | ||||||||||||
| Nephila clavata | ||||||||||||
| L. Koch , 1878 |
Nephila clavata is a species of spider in the family of silk spiders (Nephilidae). The distribution area extends over parts of Southeast Asia from India to Japan . The species is called in Japanese Jorō-Gumo (女郎 蜘蛛 , literally: "prostitute spider ").
features
As with many representatives of the family, the sexual dimorphism of this species is enormous in terms of size. The body length of an adult female is two to three centimeters. The body length of the males corresponds roughly to the length of the front body ( prosoma ) of the females.
The female has a strikingly colored, elongated rear body ( opisthosoma ). When viewed from the side, the rear body resembles a trapezoid that opens upwards . The opisthosoma is about twice as long as the prosoma . It is conspicuously patterned on the upper side, whereby the drawings look different depending on the specimen: Some animals have a yellow-gray patterned opisthosoma with larger black areas, in other specimens the pattern is yellow-gray throughout. On the underside, the young animals have two longitudinal stripes and between these stripes there are mainly lighter drawings on the back. With age, these drawings become more extensive and can even grow together into a third vertical stripe.
In younger animals there is a yellow longitudinal ligament on the sternum, which becomes narrower with age, and mostly only the anterior and posterior part of this ligament remains in the adult female. There are four lighter spots on the sides of the sternum.
On the side and on the underside, the opisthosoma has a striking red area that ends in a hill on which the spinnerets are located. The legs are dark to black in color and have a striking yellow ring.
The males are less conspicuously colored. The opisthosoma is elongated and has a dark line on the upper side, which consists of several trapezoids and is lined with two white lines. The sides of the opisthosoma are gray with white highlights. The underside shows a dark line, which is lined with two white lines. The legs are patterned similar to those of the female, with the ringing being matt white instead of bright yellow.
Distribution and subspecies
The species Nephila clavata is divided into two subspecies : (As of October 2017)
- Nephila clavata caerulescens Ono , 2011
- Nephila clavata clavata L. Koch , 1878
The distribution area of N. c. clavata extends in Southeast Asia from India to Japan . In Japan, in addition to N. c. clavata also the subspecies N. c. caerulescens , which is endemic there . The species itself is the only silk spider species in Japan and occurs on the main Japanese islands ( Honshū , Shikoku , Kyushu ) and the Ryūkyū Islands . You can often see them in autumn in gardens, parks and in the branches of trees near streets and on dirt roads.
Way of life
The animals build large wheel nets in the shape of a horseshoe . The filaments run irregularly on the front and back of the net. When viewed from the side, the threads therefore create a three-dimensional effect. If a prey gets caught in the web, the spider will immediately bite the prey once or twice. Only then is the victim wrapped in spider silk.
There are often males at the edges of the nets, waiting for a chance to mate with the female. The females lay the eggs on a tree trunk, on a building wall or on the underside of a leaf. The eggs are glued to the surface with special threads and stay there during the winter. Nephila clavata is annual, the adults die when winter sets in. The young hatch in the following spring (especially in May). The number of eggs depends on the food available. The less food the female gets, the fewer eggs she will produce.
Nets of Nephila clavata
cannibalism
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Web links
Nephila clavata in the World Spider Catalog
Individual evidence
- ↑ a b c d Sekine Mikio: Nephila clavata (Tetragnathidae) online ( Memento from August 18, 2012 in the Internet Archive ) (Internet archive). As of October 27, 2007.
- ↑ a b Friedrich Dahl , Seidenspinne und Spiderenseide , in: Messages from the Zoological Museum in Berlin, Berlin 1912
- ↑ Natural History Museum of the Burgergemeinde Bern: World Spider Catalog Version 18.5 - Nephila . Retrieved October 16, 2017.
- ↑ NI Platnick: http://research.amnh.org/entomology/spiders/catalog/NEPHILIDAE.html Status 2007. The world spider catalog, version 8.0. American Museum of Natural History
- ↑ a b Sekine Mikio: The biting behavior of the orb web spider, Nephila clavata . Description of the biting behavior in English. Status October 27, 2007 online ( Memento from May 28, 2012 in the Internet Archive ) (Internet archive)
- ^ Tadashi Miyashita: Decreased reproductive rate of the spider Nephila clavata, inhabiting small woodlands in urban areas. Ecological Research 5, Volume 3, 1990: pp. 341-351. Abstract