Sydney funnel web spider
| Sydney funnel web spider | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Sydney funnel- web spider ( Atrax robustus ), female, museum specimen in the Australian Museum |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Atrax robustus | ||||||||||||
| OP Cambridge , 1877 |
The Sydney funnel- web spider ( Atrax robustus ) is a web spider of the genus Atrax and belongs to the family Atracidae . It is one of three species in the genus and occurs both in the metropolitan area and in the Sydney area. Their bite can also pose a significant threat to humans.
features
.jpg)
The body length of the Sydney funnel-web spider without chelicerae and spinnerets is about 35 millimeters in the female and about 25 millimeters in the male. The spider's physique resembles that of other members of the family. Carapace , chelicerae and extremities have a shiny metallic dark brown to black color. The opisthosoma also has a similar basic color, but has a fluffy, shiny appearance on the top.
Similar species
Species similar to the Sydney funnel- web spider can be found in the family Atracidae , including the species Hadronyche modesta , which is also found in Australia .
Occurrence
The name-giving distribution area of the Australian species is the city of Sydney . To the north it extends to the Central Coast, to the east it is bounded by the coast, to the south it extends to the Illawarra region and to the west it borders the Blue Mountains . The preferred habitats are mainly coastal, highland and open forests with tall trees, where the ground-dwelling Sydney funnel-web spider makes its nets.
Way of life
The Sydney funnel-web spider lives in tunnel-like holes in the ground, preferably in a damp and cool environment, which are lined with funnel-shaped or tubular nets and are often found in a protected location under stones or dead wood. It consists of a white silk-like tube that is usually around 60 centimeters long and serves as the spider's abode. The T- or Y-shaped exit is provided with several struts for stabilization. In addition to its function as a retreat, the net construction also serves to catch prey and is functionally similar to the funnel webs of other spiders that build them. In addition to other arthropods , the prey scheme also includes small vertebrates such as smaller amphibians and reptiles .
The females spend most of their lives here and rarely leave the burrow. One reason for this can be rainwater penetrating the building, which is why the spiders are more often found in human dwellings where they seek protection. The males also find their way into houses on their nightly forays in search of mating.
Bite and poisonous effect
The Sydney funnel web spider's bite can be fatal to humans. An antidote has been available since 1981 and no further deaths have been reported since - from 1927 to 1981, 13 people died as a result of a bite. The toxin effect is mainly due to a protein called delta atracotoxin , which is the subject of much research - similar to the poison of other dangerous spiders (such as the Brazilian wandering spider Phoneutria nigriventer ), the poison acts directly on the nervous system of humans. What is particularly noteworthy is the fact that the poison is especially dangerous for humans, primates and newborn mice, while it has little effect on many other mammals (such as dogs and cats). The antidote is obtained from the blood of animals immunized with the poison of the funnel-web spider. A funnel-web spider needs to be milked about 70 times for a dose of antidote.
The venom of the Sydney funnel-web spider is made up of several molecular elements, including the species-specific atrax or robust toxin. Further components are neurotoxic atraxin , alkaline phosphatase , aminobutyrate as free amino acids, hyaluronidase , serotonin , phosphodiesterase , polyamines , glycerin , urea , glucose , tyramine , octopamine , protease , kidney-damaging spermine and possibly kidney-damaging spermidine , GABA and pentafluoropropylate , trimethylsilopropyl ion.
The symptoms are severe local pain that lasts for at least 30 minutes, as well as reddening of the skin , sweating, goose bumps and muscle fasciculations (twitching), triggered by the acetylcholine. The catecholamine causes sweating, salivation, twitching, spasms, nausea, vomiting, abdominal cramps, miosis and an initial perioral numbness between 10 minutes and an hour after the bite. Damage to the central nervous system includes increased reflexes, cramps, anxiety, confusion, delirium, coma and generalized muscle fasciculation and spasms affecting the jaw and neck muscles. A parasympathetic miosis and later also a mydriasis affects the eye of the bite victim. In addition to dyspnea, pulmonary edema can also be a damage to the lungs. Heart damage includes initial hypotension , then hypertension lasting several hours, tachycardia , arrhythmia and hypertonic myocardial infarction and, in severe cases, hypotension and circulatory failure after several hours due to adrenergic depletion.
What is remarkable about this species of spider is that the poison of the male, which is only up to 2.5 centimeters tall, is four to six times stronger than that of the female, which is up to 4 centimeters (with legs approx. 8 centimeters), which is significantly larger. The jaws are reported to be strong enough to penetrate soft footwear or a child's fingernail. Due to the alignment and length of the jaw claws, their use is favored by the threatening gesture of the spider straightening up.
In addition to this species, there are other spiders in the Hexathelidae family that are potentially dangerous to humans, such as Hadronyche formidabilis , which occurs from northern New South Wales to southern Queensland . In contrast to Atrax robustus , the Hadronyche spiders live in trees or in rotting tree trunks. Their venom unfolds a similarly strong effect in the human body; sometimes bites of these species have to be treated with the antidote for Atrax robustus .
Systematics
The Sydney funnel-web spider received the Latin name Atrax robustus when it was first described by Octavius Pickard-Cambridge in 1877 , which has never been changed since then. Only the species received the synonyms Euctimena tibialis and Poikilomorpha montana from the Australian entomologist and arachnologist William Joseph Rainbow in 1914 .
gallery
Top view of a male
Both sexes in comparison
literature
- Gerhard G. Habermehl : poisonous animals and their weapons. Springer-Verlag, Berlin, Heidelberg 1994
- Rainer F. Foelix: Biology of the spiders. Georg Thieme Verlag, Stuttgart 1992
Individual evidence
- ↑ a b Natural History Museum of the Burgergemeinde Bern: World Spider Catalog Version 19.5 - Atrax robustus . Retrieved December 22, 2018.
- ↑ a b c Species description of the Sydney funnel-web spider on Clinical Toxinology Resources of the University of Adelane ( Link )
- ↑ Michael R. Gray: A Revision of the Australian Funnel-web Spiders (Hexathelidae: Atracinae) Records of the Australian Museum 62, pp. 285–392, 2010. (Report on the representatives of the Atracidae family occurring in Australia ( PDF, english ))
- ↑ a b Report on the components of the poison Symptoms of the Sydney funnel-web spider bite by Dr. med. Johann Josef Kleber ( Link )
Web links
- Atrax robustus in the World Spider Catalog
- Poisons Information Monograph (PIM) for Atrax robustus
- EMedicine
- Australian Museum