“Banana spider” is a common term that can lead to confusion, as it refers to different spider species, some harmless and others potentially dangerous. Understanding the distinction between “poisonous” and “venomous” is important when discussing spiders. An animal is poisonous if its toxins are harmful when ingested or touched; venomous if it injects toxins, typically through a bite or sting. Spiders, therefore, are venomous, not poisonous. This article clarifies the identities and risks associated with spiders commonly called “banana spiders.”
Unraveling the “Banana Spider” Identity
The name “banana spider” most frequently refers to two distinct types of spiders: the Golden Silk Orb-Weaver and the Brazilian Wandering Spider. These spiders differ significantly in appearance, habitat, and the effects of their venom. Accurate identification is the initial step in assessing any potential threat.
The Golden Silk Orb-Weaver, scientifically known as Trichonephila clavipes, is a large, striking spider often found in the southeastern United States, the West Indies, and parts of Central and South America. Females are considerably larger than males, with bodies ranging from 24 to 40 millimeters in length. Their abdomen is typically golden-yellow or orange-brown with distinct white or yellow spots, and their long legs feature noticeable black tufts of hair. They are often called “banana spiders” due to their large size, yellowish coloring, and the somewhat elongated shape of their abdomen.
This species is renowned for spinning large, intricate webs with a distinctive golden hue, which can span up to three feet in diameter. These webs are semi-permanent structures, repaired as needed rather than rebuilt daily, and are typically found in wooded areas, anchored between trees and shrubs. The golden color of the silk, which comes from xanthurenic acid, is thought to help attract prey or provide camouflage.
In contrast, the Brazilian Wandering Spider, belonging to the genus Phoneutria, is a ground-dwelling spider native to tropical South America, including Brazil. These spiders are large, with a body length up to 5 cm and a leg span that can reach 13 to 15 cm. They are typically hairy and brownish-grey. Unlike orb-weavers, they do not build webs for hunting but actively wander the forest floor at night in search of prey. The common name “banana spider” for this species stems from their occasional discovery in banana shipments, a behavior that has led to their reputation as stowaways. When threatened, Brazilian Wandering Spiders adopt a characteristic defensive posture, raising their front two pairs of legs high into the air, revealing a patterned underside.
Another large, yellow and black orb-weaving spider, the Yellow Garden Spider (Argiope aurantia), is sometimes confused with “banana spiders” due to its similar coloration and prominent webs. Females of this species have a striking black and yellow patterned abdomen and build large, circular webs that often feature a distinctive zigzag pattern made of silk. Its venom is considered harmless to humans.
Understanding Their Venom and Bites
The medical significance of “banana spider” bites varies considerably by species. The Golden Silk Orb-Weaver’s venom poses a low risk to humans. Bites from this species are rare and typically occur only if the spider feels threatened or is handled roughly.
Symptoms from a Golden Silk Orb-Weaver bite are usually localized and mild, resembling a bee sting. Individuals might experience immediate, localized pain, redness, and some swelling at the bite site. Itchiness can also occur, but these symptoms generally resolve quickly without the need for medical intervention.
However, the Brazilian Wandering Spider’s venom is potent and medically significant. This spider is recognized for having some of the most toxic neurotoxic venom among spiders. A bite from a Brazilian Wandering Spider can lead to a range of severe systemic symptoms.
Initial symptoms often include intense burning pain at the bite site, accompanied by sweating and goosebumps. Within approximately 30 minutes, more widespread symptoms can develop, such as fluctuations in blood pressure and heart rate, nausea, abdominal cramping, and blurred vision. Other reported effects include muscle cramps, generalized tremors, vertigo, and in males, priapism (a prolonged and painful erection). In severe instances, respiratory distress or cardiac issues can arise, making these bites a medical emergency.
Responding to an Encounter
A cautious approach is warranted when encountering any spider. Prevention is key to minimizing encounters with spiders around your living spaces.
Seal cracks and gaps in windows, doors, and foundations to prevent spiders from entering homes.
Regular cleaning, including vacuuming and dusting, helps remove webs and reduce insect prey.
Keep outdoor areas tidy by trimming vegetation away from the house.
Check items left on the ground, such as shoes or clothing, to deter spiders.
If you encounter a Golden Silk Orb-Weaver, leave it undisturbed. Should a bite occur, basic first aid measures are usually sufficient. Clean the bite area gently with soap and water, then apply a cool compress or ice pack to reduce pain and swelling. Over-the-counter pain relievers can help with discomfort, and antihistamines may alleviate itching. Monitor the bite for any signs of worsening symptoms, such as increased redness, swelling, or persistent pain, and seek medical advice if these occur.
If you suspect a bite from a Brazilian Wandering Spider, immediate emergency medical attention is necessary. Call emergency services or transport the individual to the nearest hospital. Antivenom is available for severe envenomations and can be administered by medical professionals. When safe to do so, taking a clear photograph of the spider can assist medical personnel in identification and treatment. Avoid direct contact with any unknown spider.