Dolomedes aquaticus
| Dolomedes aquaticus | ||||||||||||
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Dolomedes aquaticus |
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| Scientific name | ||||||||||||
| Dolomedes aquaticus | ||||||||||||
| Goyen , 1888 |
Dolomedes aquaticus is a amphibious living nature of the genus Dolomedes within the family of hunting spiders (Pisauridae). This hunting spider isnativeto New Zealand .
distribution
Dolomedes aquaticus occurs on the gravel banks of New Zealand's rivers. It lives on the entire South Island and in the southern part of the North Island and is absent on the offshore small islands.
description
Females of Dolomedes aquaticus reach body lengths between 12.6 and 26 millimeters, males only 7.9 to 18 millimeters. The cephalothorax is yellow-brown in color, the region behind the eyes is orange-brown; in addition, two indistinct, dark, orange-brown bands on both sides extend lengthways backwards, which are hairy with white hair. The sternum is dark orange-brown. The abdomen is light gray in color, it bears a yellow, heart-shaped spot in the middle, the sides are hairy with thick white felted hair. On the legs, the femur, patella and first third of the tibia are straw-colored with orange-brown joints, the distal portion of the tibia is orange-brown, metatarsi and tarsi are dark orange-brown. Metatarsi and tarsi have dense adhesive hair pads (scopulae). The species can safely be distinguished genitally morphologically from the other New Zealand Dolomedes species. The shape of the retrolateral epiphysis of the tibia of the male pedipalp and the shape of the female epigyne are characteristic .
Way of life
Dolomedes aquaticus is a habitat specialist of open, unforested banks of fast flowing rivers with branched courses. It lives between rubble and stones in the shore zone. She hunts at night. Although they are basically opportunistic hunters of small arthropods, their main hunting strategy is to collect animals from the surface of the water and the hatching adults of aquatic insect groups such as stone flies and caddis flies . It also hunts from the bank with its hind legs anchored in the bank vegetation. The species can locate prey based on the vibrations of the water surface. During the day it hides in gaps under stones on the shore. If it is disturbed during the day, it escapes over the surface of the water, or it hides under water, the surface of the body is covered by a film of air. It can remain submerged for about 30 minutes.
Adult spiders are found from September to May, with a maximum in January. Females carry the fertilized eggs in an Eisack in the Chelicerae , observed from September to April. The newly hatched young are defended by the mother in a hiding place spun between stones.
Dolomedes aquaticus is host species of spider wasp Sphictostethus nitidus . This wasp, also endemic to New Zealand, paralyzes various species of spiders with its venomous sting. She then brings the host animals to a cave where she lays her eggs in the spider. The wasp larvae develop as parasitoids in the spider and eventually kill it.
Taxonomy
The species was first described by P. Goyen in 1888 . The genus Dolomedes comprises around 100 species and is distributed worldwide. Four species of the genus live in New Zealand. With one of them, Dolomedes minor , hybridization was detected using genetic markers .
Web links
Dolomedes aquaticus in the World Spider Catalog
Individual evidence
- ^ A b David S. Williams: The Physiological Optics of a Nocturnal Semi-Aquatic Spider, Dolomedes aquaticus (Pisauridae). In: Journal of Nature Research C . 34, 1979, pp. 463-469 ( PDF , free full text).
- ↑ a b c d C.J. Vink & N. Dupérré (2010): Pisauridae (Arachnida: Araneae). Fauna of New Zealand 64. 60 pp. Full text download
- ↑ Michelle J. Greenwood, Angus R. McIntosh: Flooding Impacts on Responses of a Riparian Consumer to Cross-Ecosystem Subsidies . In: [[Ecology (journal) |]] . tape 89 , no. 6 , June 2008, p. 1489-1496 , doi : 10.1890 / 07-0749.1 .
- ^ First description in the Transactions and Proceedings of the Royal Society of New Zealand 1887
- ↑ Vanessa L. Lattimore, Cor J. Vink, Adrian M. Paterson, Robert H. Cruickshank: Unidirectional introgression within the genus Dolomedes (Araneae: Pisauridae) in southern New Zealand . In: Invertebrate Systematics . tape 25 , no. 1 , January 2011, p. 70-79 , doi : 10.1071 / IS11001 .