Phoneutria nigriventer

Phoneutria nigriventer is a species of an extremely venomous spider in the family Ctenidae, found in South America (Brazil, Uruguay, Paraguay, and Argentina).[1] Along with Phoneutria fera, it is sometimes called the Brazilian wandering spider.[2]

Phoneutria nigriventer
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Ctenidae
Genus: Phoneutria
Species:
P. nigriventer
Binomial name
Phoneutria nigriventer

Its bite can cause a penile erection (priapism) that lasts for several hours.[3]

Description

Phoneutria nigriventer is a large spider. Its maximum body length is around 5 cm and its legs can span 15 cm in larger individuals. Its body is covered in thick brown hair. A prominent dark spot is present on the ventral abdomen.[4]

Toxicity and prey

The venom of the spider Phoneutria nigriventer has been reported to contain at least six neurotoxic peptides globally known as PhTx3 and individually identified as Tx3-1 to Tx3-6.[5] Tx3-3 has also been named ω-Phoneutria nigriventer toxin ω-PnTx3-3[6] and Tx3-4, phonetoxin IIA or ω-Ptx-IIA[7]. These toxins act as broad-spectrum calcium channel blockers that inhibit glutamate release, calcium uptake and also glutamate uptake in neural synapses. At deadly concentrations, these neurotoxins causes loss of muscle control and breathing problems, resulting in paralysis and eventual asphyxiation. In addition, the venom causes intense pain and inflammation following a bite, due to an excitatory effect the venom has on the serotonin 5-HT4 receptors of sensory nerves. This sensory nerve stimulation causes a cascading release of neuropeptides such as substance P, which triggers inflammation and pain.[8] The median lethal dose (LD50) of the venom is 134 µg/kg.[9] Differences between the venom of male and female Phoneutria nigriventer have been reported, with females producing a greater quantity of venom.[10]

Aside from causing intense pain, the venom of the spider can also cause priapism in humans. Erections resulting from the bite are uncomfortable, can last for many hours and can lead to impotence. A component of the venom, (Tx2-6), is being studied for use in erectile dysfunction treatments.[11][12]

The amount of P. nigriventer venom necessary to kill a 20 g mouse has been shown to be only 6 μg intravenously and 134 μg subcutaneously as compared to 110 μg and 200 μg respectively for Latrodectus mactans (Southern black widow). This ranks Phoneutria venom among the most deadly spider venoms to mice. The Brazilian wandering spider's prey also includes crickets, katydids, mantids, as well as larger animals, including tree frogs, lizards and bats.[13] Some biologists consider the Brazilian wandering spider as the most venomous spider in the world.[14]

References
  1. "Taxon details Phoneutria nigriventer (Keyserling, 1891)", World Spider Catalog, Natural History Museum Bern, retrieved 2017-04-27
  2. "Wandering spider". Encyclopædia Britannica online. 2010-09-30. Missing or empty |url= (help)
  3. Natural Viagra: Spider Bite Causes Erection
  4. Szalay, Jessie. "Brazilian Wandering Spiders: Bites & Other Facts". Live Science. Retrieved 14 April 2020.
  5. do Nascimento Cordeiro, Marta; Gomes de Figueiredo, Suely; do Carmo Valentim, Ana; Ribeiro Diniz, Carlos; von Eickstedt, Vera Regina D.; Gilroy, John & Richardson, Michael (1993). "Purification and amino acid sequences of six Tx3 type neurotoxins from the venom of the Brazilian 'armed' spider Phoneutria Nigriventer (Keys.)". Toxicon. 31 (1): 35–42. doi:10.1016/0041-0101(93)90354-l. PMID 8446961.
  6. Leão RM, Cruz JS, Diniz CR, Cordeiro MN, Beirão PS (2000). "Inhibition of neuronal high-voltage activated calcium channels by the ω-Phoneutria nigriventer Tx3-3 peptide toxin". Neuropharmacology. 39 (10): 1756–1767. doi:10.1016/s0028-3908(99)00267-1. PMID 10884557.
  7. Cassola, AC; Jaffe, H; Fales, HM; Afeche, SC; Magnoli, F; Cipolla-Neto, J. (1998). "ω-Phonetoxin-IIA: a calcium channel blocker from the spider Phoneutria nigriventer". Pflügers Archiv European Journal of Physiology. 436 (4): 545–552. doi:10.1007/s004240050670. PMID 9683727.
  8. "Phoneutria nigriventer spider venom activates 5-HT4 receptors in rat-isolated vagus nerve". Nature.com. Retrieved 2012-10-16.
  9. Venomous Animals and their Venoms, vol. III, ed. Wolfgang Bücherl and Eleanor Buckley
  10. Herzig V, John Ward R, Ferreira dos Santos W (2002). "Intersexual variations in the venom of the Brazilian "armed" spider Phoneutria nigriventer (Keyserling, 1891)". Toxicon. 40 (10): 1399–406. doi:10.1016/S0041-0101(02)00136-8. PMID 12368110.
  11. "Venom From the Banana Spider Could Be the New Viagra". National Geographic, September 10, 2012. Accessed July 9, 2019.
  12. Natural Viagra: Spider bite causes prolonged erection. Live Science, April 30, 2007. Accessed July 9, 2019.
  13. Venomous Animals and their Venoms, vol. III, ed. Wolfgang Bücherl and Eleanor Buckley
  14. Administration (2018-03-28). "Does Australia have the world's deadliest spiders?". The Lighthouse. Retrieved 2020-04-02.


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