Jorō (Trichonephila clavata)

The Joro spider is a big, colorful spider that originally came from places like Japan, Korea, China, and Taiwan. But guess what? Scientists found them in North America in 2015! They’ve changed the group they belong to a couple of times. They used to belong to the Nephila genus. Lots of Spider fans find them really interesting.

Scientific Classification

• Family: Araneidae
• Genus: Nephila
• Scientific name: Nephila clavata

Physical Description and Identification

Adults

• Size: Female spiders are 0.66 – 0.98 inches (1.7 – 2.5 cm) and males are 0.27-0.39 inches (0.70 – 1 cm). Females might have leg spans measuring 3 – 4 inches (7.62 – 10.16 cm)
• Color: Female spiders have deep blue and yellow bands on their legs, and the abdomen is an infusion of red, yellow, and black in beautiful asymmetrical patterns. Males are not that attractive as they have brown bodies.
• Other Characteristic Features: Both males and females have an elongated abdomen and long banded legs.

Eggs

Females make an egg sac on a silken base and lay around 400-1500 eggs in that. The sac remains covered with bright yellow silk, attached to branches or any human construction. The eggs overwinter and hatch the following spring.

Spiderlings

The spiderlings disperse from their mother upon maturation.

The Web

Female jorō spiders create big basket-shaped webs, having yellow silken threads, appearing brighter when exposed to sunlight. Unlike other orb spider webs, the three-layered web has one central orb accompanied by two asymmetrical layers, both at the orb’s front and backside.

Are Jorō Spiders Venomous?

Yes, Jorō Spiders do have venom. They use it mostly to catch their bug meals. But for people, it’s not very strong.

Can Jorō Spiders Bite?

Jorō Spiders can bite if they feel cornered. However, they usually like to keep to themselves and avoid people.

Ecological Importance and Behavior of Joro Spider

The Joro Spider plays a vital role in controlling insect populations by primarily feeding on various insects. This helps maintain a balanced ecosystem and reduces the number of pest insects, indirectly benefiting human agriculture and living spaces.

Natural Predators: Despite their impressive size and vibrant colors, Joro Spiders have predators such as birds and larger spiders. While their bright colors are advantageous for attracting mates and deterring smaller predators, they can also make them more visible to these larger threats.

Prey-Predator Dynamics: The Joro Spider is an important player in its ecological community, controlling insect populations while providing food for larger predators. This delicate balance ensures the stability and health of their ecosystem.

Relationship with Humans: The arrival of the Joro Spider in North America has sparked interest and curiosity. Their bright colors and intricate webs have fascinated us, but it’s crucial to respect their space and understand their role in the ecosystem. Also, biotechnology has used the genes of the Joro Spider to create stronger and softer silk, showing potential benefits for human industry.

Quick Facts

Did You Know

• In Japanese mythology, the spider is described as a “whore spider” and “entangling or binding bride.” This is because it is known to transform into a seductive woman to allure men first and subsequently devour them. According to Korean belief, the spider is known as “shaman” or “fortune teller.”
• Masao Nagasaki and his research team succeeded in creating a silken thread at the Shinshu University by injecting the eggs of silkworm with this spider’s genes. The resultant silk seemed much more durable and soft than the conventional ones.

In conclusion, with its vibrant colors, intricate webs, and ecological significance, the Joro Spider stands out as a remarkable member of the spider world.