Trichonephila

''Trichonephila'' is a genus of golden orb-weaver spiders that was first described by Friedrich Dahl in 1911, as a subgenus of '' Nephila''. ''Trichonephila'' was elevated to a genus by Kuntner ''et al.'' in 2019.

Distribution and habitat

''Trichonephila'' can be found living in Africa, Oceania, Asia, Central America, the West Indies, South America, and the US' southeastern region and gulf states. These spiders like to make webs where prey is fruitful, often in open wooded areas, between tree branches, shrubs, tall grasses, and around light fixtures. Males are more active in the months of July to September, while the females are most active late into fall.

Species

the genus includes twelve species and fourteen subspecies, found in Africa, Oceania, Asia, and the Americas:
*'' Trichonephila antipodiana'' ( Walckenaer, 1841) – China, Philippines to New Guinea, Solomon Is., Australia (Queensland)
*'' Trichonephila clavata'' ( L. Koch, 1878) – India to Japan. Introduced to Georgia-USA
**'' Trichonephila c. caerulescens'' (Ono, 2011) – Japan
*''Trichonephila clavipes'' (Linnaeus, 1767) (type) – USA to Argentina. Introduced to São Tomé and Príncipe
**'' Trichonephila c. fasciculata'' ( De Geer, 1778) – USA to Argentina
**'' Trichonephila c. vespucea'' (Walckenaer, 1841) – Argentina
*''Trichonephila edulis'' (Labillardière, 1799) – Australia, New Guinea, New Caledonia, New Zealand
*'' Trichonephila fenestrata'' ( Thorell, 1859) – South Africa
**'' Trichonephila f. fuelleborni'' (Dahl, 1912) – East Africa
**'' Trichonephila f. venusta'' ( Blackwall, 1865) – West, Central Africa
*'' Trichonephila inaurata'' (Walckenaer, 1841) – Mauritius, Réunion
**'' Trichonephila i. madagascariensis'' (Vinson, 1863) – South Africa to Seychelles
*'' Trichonephila komaci'' (Kuntner & Coddington, 2009) – South Africa, Madagascar
*'' Trichonephila plumipes'' ( Latreille, 1804) – Indonesia, New Guinea, Australia, New Caledonia, Vanuatu, Solomon Is., New Ireland
*'' Trichonephila senegalensis'' (Walckenaer, 1841) – West Africa to Ethiopia
**'' Trichonephila s. annulata'' (Thorell, 1859) – Namibia, South Africa
**'' Trichonephila s. bragantina'' (Brito Capello, 1867) – Central Africa
**'' Trichonephila s. hildebrandti'' (Dahl, 1912) – Madagascar
**'' Trichonephila s. huebneri'' (Dahl, 1912) – East Africa
**'' Trichonephila s. keyserlingi'' (Blackwall, 1865) – Congo, East Africa
**'' Trichonephila s. nyikae'' ( Pocock, 1898) – East Africa
**'' Trichonephila s. schweinfurthi'' ( Simon, 1890) – Yemen
*'' Trichonephila sexpunctata'' (Giebel, 1867) – Brazil, Paraguay, Argentina
*'' Trichonephila sumptuosa'' ( Gerstäcker, 1873) – East Africa, Yemen (Socotra)
*'' Trichonephila turneri'' (Blackwall, 1833) – West, Central Africa
**'' Trichonephila t. orientalis'' (Benoit, 1964) – Central, East Africa

Description

A spider's body comprises two regions: the prosoma or cephalothorax (anterior end) and the opisthosoma or abdomen (posterior end). Both regions are responsible for their own functions and are linked by a narrow stalk called a pedicel. The prosoma is segmented and protected by the sternum, carapace, and a plate on the dorsal and ventral sides. The prosoma houses the central nervous system, and oversees nervous integration, movement and food uptake. Also connected are the eyes, chelicerae, maxilla, sternum, fangs and four leg pairs. The opisthosoma contains the spider's digestive, circulatory, respiratory, and reproductive systems in addition to the spinnerets, which produce silk.

Behavior

Sexual dimorphism

Female spiders are larger and dominate. One reason for the size difference is that following their mating sequence, the females sometimes cannibalize their mating partner. Male spiders fight over female partners, leaving the dominant spider to mate and potentially be killed by the female. Typically, female spiders choose a small male partner.

Courtship

Courtship dance involves a male mating dance, attempting attract females. This dance involves multiple functions. To begin the courtship, a male must find a female’s web and make vibrations to let her know he’s not prey. It is common for the male to be mistaken as prey and eaten alive by the females before they mate. The vibrating reduces the risk of aggravating the female.

Environmental adaptations

Males are the sex that leaves their webs and seeks a female. ''Trichonephila'' webs have a yellow colour due to the xanthurenic acid produced in its silk. It is thought that this colour helps attracti prey. The genus exhibits behavioural adaptations to the heavy rainfall of its tropical ecosystems. Upon heavy rain, the spider hangs off its web from only its fourth pair of legs, which in turn reduces rain impact damage and helps with draining the water off the web.

References

Nephilidae
Araneomorphae genera

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