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.
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
Other Names
East Asian Joro spider, Jorou spider, joro-gumo(Japanese) and Mudang spider(Korea)
Distribution
North America (Northeast Georgia), China, Korea, Taiwan, and Japan
Habitat
Forests and human habitations
Diet
Insects
Web Type
Orb web
Lifespan
Around 1 year
IUCN Conservation Status
Least Concern
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.
A female Jorō spider’s body can grow between 0.66 to 0.98 inches, but its total leg span can reach an impressive 3 to 4 inches. This size makes them significantly larger than the males of the species, which are much smaller and less conspicuous in comparison to the vibrant females.
A female Jorō spider builds a large, distinctive three-layered web that appears basket-shaped. The silk threads have a characteristic yellow hue, which looks brighter in sunlight. Unlike a standard orb web, it has a central orb with two additional, asymmetrical layers positioned in front of and behind it.
Yes, Jorō spiders are venomous, but their venom is not considered medically significant to humans. They primarily use it to subdue insect prey they capture in their webs. A bite is unlikely and typically occurs only if the spider feels trapped, with effects being minimal for most individuals.
You can identify a female Jorō spider by its vibrant coloration and large size. Look for an elongated abdomen with asymmetrical patterns of red, yellow, and black. Her long legs will also have distinct deep blue and yellow bands, making her visually striking compared to other common spiders.
A single female Jorō spider lays between 400 and 1,500 eggs inside one egg sac. This sac is constructed on a silken base and covered with bright yellow silk for protection. The eggs remain inside the sac to overwinter before the spiderlings hatch during the following spring season.
Yes, male and female Jorō spiders look very different from one another. Females are large and brightly colored with yellow, blue, red, and black patterns on their abdomen and legs. In contrast, males are much smaller, have a slender, plain brown body, and lack the vibrant coloration.
The Jorō spider originally comes from East Asia, with a native range that includes Japan, Korea, China, and Taiwan. It is considered an introduced species in North America, where it was first officially identified by scientists in 2015 after establishing populations in the southeastern United States.
Dr. James Watuwa on July 27, 2019.
Spider Team
