Trichonephila clavata

Trichonephila clavata, Photo: Kinori

Life-forms

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Subphylum: Chelicerata
Classis: Arachnida
Ordo: Araneae
Subordo: Opisthothelae
Infraordo: Araneomorphae
Taxon: Neocribellatae
Series: Entelegynae
Superfamilia: Araneoidea

Familia: Araneidae
Subfamily: Nephilinae
Genus: Trichonephila
Species: T. clavata

Trichonephila clavata, also known as the Joro spider (ジョロウグモ（女郎蜘蛛、上臈蜘蛛, Jorō-gumo), is a member of the Trichonephila genus. The spider can be found throughout Japan (except Hokkaidō), Korea, Taiwan, China. Due to its large size and the bright, unique colors of the female Trichonephila, the spider is well-favored in Japan.[citation needed]

Scientists confirmed the first known occurrence of T. clavata in North America in 2014,[3], and as of October 2022, T. clavata's range spans at least 120,000 km2 (46,000 sq mi), occurring across Georgia, South Carolina, North Carolina, and Tennessee, with additional reports in Alabama, Maryland, Oklahoma, and West Virginia. Its pattern of spread suggests it is primarily driven by natural dispersal mechanisms, such as ballooning, though human-mediated transport cannot be discounted.[4][3][5][6][7]

In 2019, this species was moved from the genus Nephila to Trichonephila. T. clavata's congener Trichonephila plumipes is commonly found in Australia. It also was moved from Nephila to Trichonephila, along with 10 other species.[8]
Characteristics
Female seen from below

Trichonephila clavata pass winter as eggs and scatter as tiny juveniles in the spring. The adult female's body size is 17–25 mm, while the male's is 7–10 mm.

The web of females may reach several meters in length. In sunlight, the yellow threads appear to be a rich gold color. The structure of the web seen in cross-section is unusual for an orb web; it has three layers: the central orb, plus two irregular layers in front and behind the orb.

The adult female individual has stripes of yellow and dark blue, with red toward the rear of the abdomen. In autumn, smaller males may be seen in the webs of the females for copulating. After mating, the female spins an egg sack on a tree, laying 400 to 1500 eggs in one sack. Her lifecycle ends by late autumn or early winter with the death of the spider. The next generation emerges in spring.

Although the spider is not aggressive, they will bite to protect themselves. The bite is considered painful, but not life-threatening.[9]
Silk strength and applications

Researchers led by Masao Nakagaki at Shinshu University, Japan, have succeeded in creating a silk thread that is stronger, softer, and more durable than conventional silk by injecting silkworm eggs with genes of the Jorō spider. The silkworms that hatch weave cocoons containing 10% spider protein. The dragline silk is said to have many uses, such as for bulletproof vests, sutures after an operation, fishing line, nets, and tennis rackets. A Japanese manufacturer, Okamoto, began developing commercial applications for the silk and planned to release extra-thin, durable spider socks by 2010.[10][11][needs update]
In folklore

Jorōgumo is a legendary creature in Japanese folklore. A Jorōgumo is a spider who can change her appearance into that of a beautiful woman. She's said to breathe fire and to be able to control other spiders.[12] She seeks men to seduce, whom she then binds in her silk and devours.
This spider was about 5 cm long. The large one is the female and the smaller one in the background is the male - filmed in Tokyo, Japan on September 29, 2013
Introduced species in North America

The spider is an introduced species in northeast Georgia and northwest / upstate South Carolina in North America. They were first spotted in Hoschton, Georgia in 2013. Since then, they have been spotted in numerous locations in northeast Georgia, including the Athens, Georgia area, and also in Greenville, South Carolina. It is believed that the species will become naturalized. They are expected to colonize much of the Eastern Seaboard of the United States due to their relative imperviousness to the cold.[13][14]

As of 2022, their impact on their new ecosystem is unknown. They have been observed catching the brown marmorated stink bug (Halymorpha halys), an invasive species that native spiders have not been known to eat, and it has also been hoped that they may consume mosquitoes and flies. Some hope that the impact of the species will be positive due to their harmless nature and consumption of primarily invasive or nuisance insects; however, because of the relative lack of information about its ecology, the effects the spider will have on ecosystems are unknown.[14][15]

See also

Joro toxin
Tegenaria parietina

References

Kuntner, M.; Rudolf, E.; Cardoso, P. (2017). "Nephila clavata". IUCN Red List of Threatened Species. 2017: e.T89292211A89292868. doi:10.2305/IUCN.UK.2017-1.RLTS.T89292211A89292868.en. Retrieved 25 July 2023.
"Taxon details Trichonephila clavata (L. Koch, 1878)". World Spider Catalog. Natural History Museum Bern. Retrieved 2017-05-14.
Hoebeke ER, Huffmaster W, Freeman BJ (2015-02-05). "Trichonephila clavata L Koch, the Joro Spider of East Asia, newly recorded from North America (Araneae: Nephilidae)". PeerJ. 3: e763. doi:10.7717/peerj.763. PMC 4327315. PMID 25699210.
Chuang, A. (2023). "The Jorō spider (Trichonephila clavata) in the southeastern U.S.: an opportunity for research and a call for reasonable journalism". Biol Invasions. 25: 17–26. doi:10.1007/s10530-022-02914-3. S2CID 253475825.
"Scientists confirm first North American record of East Asian Joro spider". SciGuru. 2015-03-17.
Shearer L (30 October 2014). "Madison County man captures spider never before seen in North America". Athens Banner. Archived from the original on 26 October 2020.
Drake N (2015-03-19). "Asian "Fortune-Teller" Spider Found in U.S. for First Time". National Geographic. Archived from the original on 3 March 2016.
Kuntner, Matjaz; Hamilton, Chris; Cheng, Ren-Chung; Gregorič, Matjaž; et al. (2019). "Golden Orbweavers Ignore Biological Rules: Phylogenomic and Comparative Analyses Unravel a Complex Evolution of Sexual Size Dimorphism" (PDF). Systematic Biology. 68 (1147): 555–572. doi:10.1093/sysbio/syy082. PMC 6568015. PMID 30517732.
"Are Joro Spiders Dangerous?".
"Silk Socks, a New Biotech Product". The Silkworm Blog. 10 December 2007.
"Soon, socks and bulletproof vests made from spider silk". Thaindian News. 12 October 2007. Archived from the original on 2 October 2018. Retrieved 29 October 2009.
"The Legend of the Jorōgumo". Joro Spider Information. Retrieved 17 June 2022.
Romo, Rebecca (9 March 2022). "No, you don't need to worry about joro spiders. They may even be helpful in some ways". NPR. Retrieved 9 March 2022.
Gravrilles, Beth (26 October 2020). "Like it or not, Joro spiders are here to stay". UGA TODAY. Athens, Georgia. Retrieved 30 September 2021.
Aridi, Rasha, ‘Like a Scene Out of ‘Arachnophobia,” Invasive Spiders Take Over Northern Georgia - Scientists are torn on whether the Joro spider could have positive or negative effects on the native ecosystem, Smithsonian, November 9, 2021