Phoneutria

Lore & Background

Phoneutria are found in forests from Costa Rica southward throughout South America east of the Andes, including Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil, Paraguay, and northern Argentina. Three species occur in the Amazon region, one ranges into Central America, and the remaining species are restricted to the Atlantic Forest of Argentina, Paraguay, and Brazil. The genus has also been introduced to Chile and Uruguay. Their presence in banana shipments is occasionally reported, though many such reports involve misidentifications of unrelated spiders like Cupiennius.

Reader's Guide

Phoneutria holds significance as one of the few spider genera known to pose a genuine threat to humans. Danger arises not only from venom toxicity but also from the spider's capacity and tendency to bite, its wandering nature, and its proximity to human habitation. In densely populated areas, these spiders seek dark hiding places during the day, including houses, clothes, boots, and boxes, where they may bite if disturbed. Studies indicate that Phoneutria injects venom in about one-third of bites, with only a small quantity in one-third of those cases; only about 2.3% of bites (mainly in children) require antivenom. Fatalities, though rare, are usually attributed to respiratory arrest. The species P. nigriventer is responsible for most envenomation cases in Brazil because it is commonly found in highly populated areas of southeastern Brazil. The genus's legacy includes ongoing challenges in identification, as Phoneutria are easily confused with non-medically significant ctenids, and many historical reports of 'banana spiders' have been based on misidentifications.

Did You Know?

• The genus name Phoneutria comes from the Greek word for 'murderess'.
• Phoneutria can deliver a defensive 'dry bite' and inject venom in only about one-third of bites.
• The largest Phoneutria species have the longest body and greatest body weight among araneomorph spiders.