Brazilian Wandering Spider

Kingdom: Animalia

Phylum: Arthropoda

Class: Arachnida

Order: Araneae

Family: Ctenidea

Genus: Phoneutria

Species: Phoneutria fera

Description

Brazilian Wandering Spiders are venomous spiders that are found mainly in tropical South America. They are also called Banana Spiders and Armed Spiders. Their body ranges from about .5-2 inches and their legs range from 5-6 inches making them fairy large spiders. Commonly dark brown and grey they can be identified by dense fine hairs all over the body region of the spider. Some but not all spiders possess dark red hairs on their jaws. The most reliable feature used to determine these spiders however is their defense posture. The spider rears up on its back legs lifting its body up and erecting its front two pairs of legs in the air and revealing its fangs.

Distribution

Given away in their name Brazilian Wandering Spiders are most commonly found in the jungles of Brazil. Their range stretches all along the Amazon Rainforest. During the day they commonly hide away in termite mounds, fallen logs or rocks, and banana plants. At night they "wander" the forest floor in search of prey.

Life Cycle

Phoneutria fera reproduce sexually. Sperm from the male is stored in a small chamber inside the female until she is ready to release it to the eggs. As the eggs are released from her into a small silk bundle called an egg sac they are fertilized. Males quickly leave after mating as it is not uncommon for the female to attack and eat the male. The eggs remain inside the egg sac until they hatch and then quickly disperse on their own. Phoneutria fera are solitary spiders and juveniles immediately begin preying on small insects. Adults feed on a wide range of prey such as large insects, mice, small frogs and lizards, and anything of that relative size. Their mating period is during the dry season (April to June) which is when most contact with humans occurs. The typical life cycle of the spider is 1-2 years.

Danger to Humans

Phoneutria fera is thought to have the most potent venom of any spider in the world. Their venom is fast acting on prey and kills in only a few minutes. Experts have proven that it takes roughly 6μg of their venom to kill a 20g mouse. The Black Widow Spider on the other hand needs roughly 110μg of its venom to kill a mouse (Szalay). Their venom contains a dangerous neurotoxin known as PhTx3. At high doses it causes loss of muscular control and breathing problems which can lead to paralysis and asphyxiation. One study done showed that the majority of bites on humans occur during March and April (30%), during the day (76%), in houses (55%), and on the hands and feet (35%) (NCBI). It is thought that Brazilian Wandering Spiders have one of the most painful bites of any spider as well. It causes extreme pain and high levels of inflammation. They have the most active venom of any living spider known. Females are thought to inject more venom in their bites.

What makes this spider so deadly to humans is their close proximity, deadly venom, and aggressive attitude. They are fast active spiders that live in close quarters to humans. They can hide in boots, small crevices in houses, and all along the jungle floor making contact with humans somewhat common. Banana plants are a favorite hideout for the spiders and it's not uncommon for bites to occur when harvesting and shipping bananas. Medical attention should be seeked immediately following a bite from this spider.

References

http://www.tandfonline.com/doi/full/10.1080/15563650802258524

http://www.bioone.org/doi/abs/10.1636/Hi13-05.1

https://openi.nlm.nih.gov/detailedresult.php?img=PMC4614586_emerg-2-054-g005&req=4

https://animalcorner.co.uk/animals/brazilian-wandering-spider/

http://www.independent.co.uk/news/uk/home-news/brazilian-wandering-spider-deadly-allegedly-found-asda-bananas-a7321206.html

https://www.livescience.com/41591-brazilian-wandering-spiders.html

https://www.ncbi.nlm.nih.gov/pubmed/10742722