Micrommata virescens

Micrommata virescens, common name green huntsman spider, is a species of huntsman spiders belonging to the family Sparassidae.

Micrommata virescens
Male of Micrommata virescens
Female of Micrommata virescens
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Sparassidae
Genus: Micrommata
Species:
M. virescens
Binomial name
Micrommata virescens
Synonyms
  • Aranea rosea
  • Aranea smaragdula
  • Aranea virescens
  • Aranea viridissima
  • Araneus roseus
  • Araneus virescens
  • Micrommata rosea
  • Micrommata roseum
  • Micrommata smaragdina
  • Micrommata viridissima
  • Micrommata viridissima valvulata
  • Sparassus smaragdulus
  • Sparassus roseus
  • Sparassus virescens
An adult male photographed from above. The red- and yellow-striped male colouration differs greatly from the cryptic green female. M. virescens is thus an example for sexual dichromatism, where strong differences in colouration are present between the sexes. [1][2]
An adult female photographed from above. The central paraxial stripe may serve as a disruptive visual element.[1][2]

Distribution

This species has a Palearctic distribution.[3] It occurs naturally in Northern and Central Europe, including Denmark and southern Britain.[4][5][6]

Description

In the females of Micrommata virescens the body length can reach 12–16 millimetres (0.47–0.63 in), while in the males it is about 7–10 millimetres (0.28–0.39 in).[7]

The cephalothorax and the long legs of the females are bright green, with a lighter green abdomen showing a darker green median stripe. The eight eyes are arranged in two rows and surrounded by white hairs.[4] Males are dark green-olive and have a narrower abdomen, with red sides and a red to red-brown median stripe bordered yellow.[8] Young spiders have a yellow-brown cephalothorax, with dark marginal and median stripes. Only after the last molting in the following spring the juveniles assume the typical coloration of the adults.

The green coloration is due to the bilin micromatabilin[9] and its conjugates in haemolymph, interstitial tissues and the yolk of oocytes.[10]

Habitat

These characteristic huntsman spiders can be found at the edges of forests, in dry meadows, in damp woodland clearings and rides, where they prefer grass and the lower branches of trees.[8]

Biology

These spiders are mainly diurnal. They do not build a web, and hunt insects in green vegetation, where they rely on their camouflage. Their green color makes them very difficult to be detected by predators.[8] They grow relatively slowly, taking 18 months to reach maturity.[4] Females are fertile from May through to September. A few days after mating, the males die. In July the females enclose the egg-sac into a few leaves stitched together.[6] Cocoons are guarded by females. After about 4 weeks eggs hatch about 40-50 young spiders.[4]

References
  1. Oxford, G. S.; Gillespie, R. G. (January 1998). "Evolution and Ecology of Spider Coloration". Annual Review of Entomology. 43 (1): 619–643. doi:10.1146/annurev.ento.43.1.619. ISSN 0066-4170. PMID 15012400.
  2. Dollinger, C. (2018). Reproductive behaviour of the green huntsman spider Micrommata virescens and its implications for sexual dichromatism. EthoNews 79, 20-22.
  3. Platnick, Norman I. (10 December 2011). "Fam. Sparassidae". The World Spider Catalog, Version 12.5. New York, NY, USA: American Museum of Natural History. doi:10.5531/db.iz.0001. Retrieved 22 April 2012.
  4. Natur-lexikon
  5. The Spiders of Europe and Greenland. Family: Sparassidae (Giant Crab Spiders) (list)
  6. "Summary for Micrommata virescens (Araneae)". British Arachnological Society. Retrieved 30 August 2016.
  7. Araneae
  8. A bug blog
  9. A. Holl & W. Rüdiger (1975). "Micromatabilin, a new biliverdin conjugate in the spider, Micromata rosea [sic] (Sparassidae)". Journal of Comparative Physiology B. 98 (2): 189–191. doi:10.1007/BF00706130.
  10. G. S. Oxford & R. G. Gillespie (1998). "Evolution and ecology of spider coloration". Annual Review of Entomology. 43 (1): 619–643. doi:10.1146/annurev.ento.43.1.619. PMID 15012400.

Further reading
  • A. Bayram & S. Özda (2002). Micrommata virescens (Clerck, 1757), a new species for the spider fauna of Turkey (Araneae, Sparassidae). Turkish Journal of Zool 26: 305–307 PDF
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