Jorō Spiders

Distinctive red on body

A member of the golden orb-web spider genus, found in warmer regions and building impressive webs, is the Trichonephila clavata, also known as the Jorō spider. Found in Japan, Korea, Taiwan, China and Georgia. They pass through winter as eggs and scatter as juveniles in the spring. The adult female’s body size is 17-25mm while the male is a little smaller at 7-10mm. The females web can be up to 1 meter in length with yellow threads. It has three layers, the central orb and 2 irregular layers, one in front, one behind.

The adult female has stripes of yellow and dark blue, red toward the the rear abdomen. I autumn you may see the male on the web, there for copulating. The female spins an egg sack on a tree and lays 400-1500 eggs. Researchers have created silk from these spiders that is stronger , softer and more durable.

The improved silk is good for bulletproof vests, sutures after an operation, tennis rackets, fishing line, and nets. In Japanese folklore, Jorōgumo spiders can change their appearance into a beautiful woman that seeks to seduce men, binds in her silk and devours. As far as Georgia goes, they were first spotted in Hoschton in 2013. They are believed to have been shipped from the Far East in shipping containers.

The spiders are also interesting as they travel by ballooning, a method where the wind carries them on a strand of their web. This is particularly interesting as it is how the male spiders travel to find their mates. In areas with many Jorō spiders, the ballooning technique is effective for the males to travel, but in areas with a small population, researchers aren’t quite sure how the males find their mates. A benefit of the new species is that they capture and feed on insects that local spiders do not- mainly the adult brown marmorated stink bug. They are in no way a threat and will not harm humans.

The first one I saw built her webs right outside my front door, She was huge.
Adult brown marmorated stink bug

Author: Doyle

I was born in Atlanta, moved to Alpharetta at 4, lived there for 53 years and moved to Decatur in 2016. I've worked at such places as Richway, North Fulton Medical Center, Management Science America (Computer Tech/Project Manager) and Stacy's Compounding Pharmacy (Pharmacy Tech).

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