The Brazilian wandering spiders, also called armed spiders or banana spiders, are part of the same family as the "murderess" in Greek. It's one of the most venomous spiders on the planet. It can be deadly to humans, especially children, but antivenom makes death unlikely.
The Brazilian wandering spider has been named the world's most venomous spider multiple times by Guinness World Records. "Classifying an animal as deadly is controversial as the amount of damage depends on the amount of venom injected," said the late Jo-Anne Sewlal, an arachnologist at the University of the West Indies in Trinidad and Tobago.
There is a classification and a taxonomy.
There are nine species of Brazilian wandering spider that can be found in Brazil. An article in the journal American Entomologist states that some of the species can be found throughout Central and South America. Richard Vetter, a research associate in the department of entomology at the University of California, Agriculture and Natural Resources, wrote that some of the powerful arachnids have been mistakenly exported to North America and Europe. In many cases of cargo invasion, the spider in question is a harmless banana spider that is mistaken for a Phoneutria. The two types of spiders are the same.
According to the Integrated Taxonomic Information System, the Brazilian wandering spiders are classified as:
Kingdom: Animalia Subkingdom: Bilateria Infrakingdom: Protostomia Superphylum.
The species:
Phoneutria bahiensis is a species.
Phoneutria boliviensis.
Phoneutria eickstedtae.
Phoneutria fera.
Phoneutria keyserlingi
Phoneutria nigriventer.
Phoneutria pertuy.
Phoneutria reidyi.
A study published in the journal ZooKeys found that Phoneutria boliviensis included two separate species from different habitats.
Size and characteristics.
The Natural History Museum in Karlsruhe, Germany, says that the Brazilian wandering spiders are large, with bodies reaching up to 2 inches (5 centimeters) and a leg span of up to 18 cm. The species are all brown and gray, with some having small colored spots on their abdomen. The University of Florida says that many species have bands of black and yellow or white on the underside of their legs.
It is behavior.
The Brazilian wandering spider is found in the tropics. The image is from phototrip/iStock.
According to Sewlal, these arachnids are called wandering spiders because they do not build webs but wander on the forest floor at night. They kill by ambush and direct attack.
They hide most of the day under logs or crevices and come out at night to hunt. They eat insects, other spiders and small animals.
The research showed that the Brazilian wandering spider, Phoneutria boliviensis, eats a mix of arthropods and reptiles. The research from the University of Tolima and the University of California found that the guts of 57 spiders identified 96 prey species, including flies, beetles, butterflies, moths, grasshoppers, and crickets. The female spiders ate lizards and snakes.
These spiders have a reputation for being aggressive because of their bite and posture. These behaviors are defense mechanisms.
They will raise their first two pairs of legs when threatened. The scarlet hair surrounding the fangs on some species is exposed by this dramatic and intimidating posture. The threat of the poisonous spider serves as a warning to the predator.
If they are provoked intentionally or accidentally, their bites are a means of self-defense.
Mating.
A spider is guarding her eggs in southeast Brazil. Credit: iStock
The female is larger than the male in almost all spider species. The Brazilian wandering spider has the same dimorphism. The biology department at the University of Wisconsin-La Crosse says that males approach females cautiously. Males perform a dance to get females' attention, and they often fight over the female. The female can be picky, and she can turn down many males before finding a partner. The male needs to watch out for females once copulation is done.
The female can store the sperm in a separate chamber from the eggs until she is ready to fertilize them. She will lay up to 1,000 eggs at a time, which are kept safe in a spun-silk egg sac.
The Brazilian wandering spiders live for a couple of years.
There are bites and venom.
The Natural History Museum in Germany says that the venom of the Brazilian wandering spiders is complex. The venom affects the victims' systems.
After a human is bitten by a spider, he or she may experience some symptoms such as burning pain at the site of the bite, sweating and goosebumps. Within 30 minutes, symptoms include high or low blood pressure, fast or a slow heart rate, nausea, abdominal cramping, hypothermia, blurred vision, convulsions, and excessive sweating associated with shock. People who are bitten by a spider should seek medical attention.
Live Science reported that the bite of a Brazilian wandering spider can cause a long, painful erection to human males. The venom increases blood flow. Several studies have looked at incorporating venom into drugs.
These bites are rare and usually mild, Vetter said. He cited a Brazilian study that showed that only 2.3% of people with bites who came to a Brazilian hospital over a 13-year period were treated with antivenom. The bites did not have enough venom to require it. The bites were from the species P. nigriventer and P. keyserlingi. According to a study in the journal Clinical Toxology in Australia, Europe, and Americas, only a small percentage of bites in Brazil are severe. In Brazil, 15 deaths have been attributed to Phoneutria since 1903.
"It is unlikely that the spider would inject all of its venom into you, as this venom is not only needed as a means of defense but to immobilize prey," he said. If it injected all of its venom, it would have to wait until it could make more of its own body. The spider would be vulnerable to being attacked.
venom production requires a lot of resources and time, according to Sewlal. If the spider were to attack frequently and use up all of its venom, it would be safe to assume that it has a ready food supply. This situation is not in the wild.
There are additional resources.
Live Science editor Laura Geggel updated the article in December of 2021.
