Giant crab spiders

from Wikipedia, the free encyclopedia
Giant crab spiders
Green hoof spider (Micrommata virescens)

Green hoof spider ( Micrommata virescens )

Systematics
Class : Arachnids (arachnida)
Order : Spiders (Araneae)
Subordination : Real spiders (Araneomorphae)
Partial order : Entelegynae
Superfamily : Sparassoidea
Family : Giant crab spiders
Scientific name of the  superfamily
Sparassoidea
???
Scientific name of the  family
Sparassidae
Bertkau , 1872

The giant crab spiders (Sparassidae; Syn .: Heteropodidae, Eusparassidae) are a family of real spiders (Araneomorphae) and the only family within the superfamily Sparassoidea . It comprises around 1209 species in 86 genera worldwide . (As of June 2016)

They got their name from similarities to the crab spiders , with which they are not very closely related. In Central Europe only one genus is native, the hush spiders ( Micrommata ) with among others the green hush spider ( Micrommata virescens ). The introduced warm-house giant crab spider ( Heteropoda venatoria ), whose main distribution is in the tropics and subtropics , also occurs in greenhouses .

description

Heteropoda maxima is the largest known giant crab spider and one of the largest spiders in the world.

Most giant crab spiders can be identified, among other things, by the position of their legs: these are slightly rotated in the hips (coxae) and therefore point more or less clearly forward, similar to the crabs . Many, but not all, giant crab spiders have an inconspicuous brown or gray color. The legs are hairy and conspicuously thorny, the body is smooth but not shiny. Some species are notable for their considerable body size (the males of the Heteropoda maxima occurring in Laos reach a leg span of 25 to 30 cm). The species of some genera have a noticeable banding of the legs, z. B. in Barylestis , Eusparassus or Holconia .

Some larger species resemble tarantulas ; however, they are not closely related.

distribution

The endemic species Cebrennus rechenbergi in the Moroccan sand desert Erg Chebbi , which can move like a flick-flick .

Giant crab spiders are found in Australia , New Zealand , Southeast Asia, the Middle East in areas around the Mediterranean Sea and very likely in many other tropical and subtropical areas. They are also found today in many parts of the world that they may not be native to, such as China , Japan , Florida , Puerto Rico, and the southwestern part of the United States and Hawaii . In principle, they can be found anywhere they can go as “stowaways” and also survive the winter.

The Senckenberg Society for Natural Research , National Science Museum Tokyo, Museum of the Institute of Zoology, Chinese Academy of Sciences and the International Rice Research Institute Manila have a research focus here. They examine the radiations in Asia ( Pseudopoda , Sinopoda ), Southeast Asia as well as Australia ( Heteropoda , Pandercetes ) and Africa. In western South Africa, family relationships and adaptations to different biomes are examined macroecologically.

Way of life

Olios giganteus with a captured snake

The giant crab spiders can often be found in sheds, garages and other little-visited places. They live in crevices in the tree bark, but are also found in houses and cars. They can run very quickly on walls and ceilings because they can also hold onto smooth surfaces.

The eyesight of these spiders is nowhere near as good as that of the jumping spiders (Salticidae). But it is sufficient to see larger animals from a few decimeters away. Giant crab spiders do not build webs , but look for food - mainly insects and other invertebrates - while wandering around.

Giant crab spider with an egg cocoon

The females vehemently defend their egg sacs and also the offspring. You then take a threatening position. If ignored, they can attack and bite.

Giant crab spiders are among the few families in which limited social behaviors have been observed, something that is generally unusual for spiders. Scientists at Cornell University carried out a study on the species Delena cancerides living in Australia , in the course of which, in addition to the said, determined readiness to defend the females against their brood, it was even confirmed that prey that had been overwhelmed by individual animals in certain cases was not there Place, but are dragged back into the hiding places of the spiders, which are mostly inhabited by several individuals, where the catch is then shared with other species. According to the observations of the researchers, this behavior appears to occur when the nocturnal D. cancerides is surprised by the sunrise during the hunt, forcing it to return to its hiding place with prey.

Noises during the mating ritual

The male of the warmhouse giant crab spider ( Heteropoda venatoria ) capable of stridulation

Males of the warm-house giant crab spider ( Heteropoda venatoria ), which has been abducted worldwide, have been observed to make noises when they think a female of the same species is nearby. Their method of making sounds is fundamentally different from the stridulation with the palps or other limbs found in species of spiders. The males anchor themselves firmly on a substrate and make the whole body vibrate. With this they announce their own females in order not to be mistaken for prey.

Systematics

The World Spider Catalog currently lists 86 genera and 1209 species for the giant crab spiders. (As of June 2016)

Web links

Commons : Giant Crab Spiders (Sparassidae)  - Collection of images, videos, and audio files

Sparassidae in the World Spider Catalog

Individual evidence

  1. ↑ a b Natural History Museum of the Burgergemeinde Bern: World Spider Catalog Version 17.0 - Sparassidae . Retrieved June 8, 2016.
  2. ^ Senckenberg Society for Nature Research - Arachnology
  3. ^ How social huntsman spiders live and hunt together , BBC Nature
  4. ↑ Rovner, JS (1980): Vibration in Heteropoda venatoria (Sparassidae): A third method of sound production in spiders. J. Arachnol., 8: 193-200. ( PDF )
  5. ↑ Cristina A. Rheims. 2019. Extraordinarius gen. Nov., A New Genus of Sparianthinae Spiders (Araneae: Sparassidae) from southeastern Brazil. Zootaxa. 4674 (1); 83-99. DOI: 10.11646 / zootaxa.4674.1.4
  6. ↑ New species of spiders described in honor of Greta Thunberg
  7. ↑ Peter Jäger. 2020. Thunberga gen. Nov., A New Genus of Huntsman Spiders from Madagascar (Araneae: Sparassidae: Heteropodinae). Zootaxa. 4790 (2); 245-260. DOI: 10.11646 / zootaxa.4790.2.3