Researchers say a child-sized spider could spread to much of the East Coast after spreading rapidly from East Asia into Georgia.
The golden web of the Joro spider took over yards across North Georgia in 2021, alarming some residents. The spider was also seen in South Carolina and entomologists expected it to spread throughout the Southeast.
A new study suggests it could spread even further. The Joro seems better suited to colder temperatures than a related species, University of Georgia researchers said in a paper published last month.
It has about double the metabolism of a golden silk spider, a 77 percent faster heart rate and can survive a brief freeze that kills its relatives, the study found.
The researchers also noted that Joros are found in much of Japan, which has a similar climate to the US
“Just looking at that, it looks like the Joros can probably survive most of the East Coast here, which is pretty sobering,” study co-author Andy Davis said in a statement.
The Jorospin, a large spider native to East Asia, is the size of a human hand and can live in the cold thanks to its metabolism and heart rate
The Joro spider has spread significantly across the US since its arrival on US soil in 2014. The spider was spotted invading southern states, including South Carolina and Georgia, but is now expected to make its way to the northeast.
The Joro, also known as the trichonephila clavata, is part of a group of spiders known as orb weavers because of their well-organized, wheel-shaped webs. The name comes from the word ‘Jorōgumo’, a type of creature in Japanese folklore who can disguise herself as a beautiful woman who preys on unsuspecting men.
Joro females are common in Japan, China, Korea and Taiwan and have colorful yellow, blue and red markings on their bodies. They can reach 8 cm in length when their legs are fully extended. Males are much plainer and only have a brown body.
It’s not clear why they’ve been so abundant this year, though experts agree their numbers have exploded.
It’s also not clear exactly how and when the first Joro spider arrived in the US, though they most likely made their way to North America by tagging along on shipping containers, according to EarthSky.
“The potential for dispersal of these spiders through the movements of humans is very high,” Benjamin Frick, co-author of the University of Georgia study on the spiders, said in a statement.
‘Anecdotally, just before we published this study, we received a report from a graduate student at UGA [the University of Georgia] who accidentally transported one of these to Oklahoma,” he added.
In Georgia, in 2014, a researcher identified the first of many about 80 miles (128 km) northeast of Atlanta, according to the Associated Press.
However, these creatures also use a technique scientists call “ballooning” to fly.
They rely on a thread of silk made from their webs to parachute from place to place through the wind. With this method, they may be able to travel between 50 and 100 miles.
Female Joro spiders also tend to place their eggs in ‘egg sacs’, which are made from their webs. They can lay about 400-1500 eggs.
The Joro is part of a group of spiders known as orb weavers because of their well-organized, wheel-shaped webs
Meanwhile, the impact of these spiders on native species and the environment is still under investigation, although some researchers believe they are benign.
Joros are venomous, but experts say they pose no threat to humans or dogs and cats, and won’t bite them unless they feel very threatened. If they do bite, it will feel like an occasional pinch because the spiders’ fangs aren’t large and sharp enough to break through human skin, according to Paula Cushing, an arachnologist at the Denver Museum of Nature & Science, that one to go on her palm.
The Joro spider, on the other hand, mainly preys on flies, mosquitoes and stink bugs, the latter posing a threat to crops and having no natural enemies. Researchers say the Joro could be a blessing in disguise for farmers and should be left alone.
“There’s really no reason to actively crush them,” Frick said. “People are at the root of their invasion. Don’t blame the Joro spider.’
More than 150 years ago, a cousin of the Joro spider, the golden silk spider, also made its way to the United States from South America and the Caribbean.
However, unlike the Joro, these spiders do not have the same body characteristics to spread across the country in different climates as they reside mainly in the southeastern US.
The life cycle of Joro spiders usually ends in late fall or early winter. The next generation then emerges in the spring.
Colorful, poisonous Joro spiders the size of a palm will take over the East Coast
The Joro spider is one of several species of orb weaver spiders belonging to the genus Trichonephila. It can be found throughout Japan, South Korea, Taiwan, and China, and now in the US, especially South Carolina and Georgia, since 2014.
Joro females have colorful yellow, blue and red markings on their bodies and are loved in Japan. They are about 1.7 to 2.5 cm in size, but the specimens found in Georgia can reach 8 cm in length when their legs are fully extended. anypest.com.
Male Joros are much plainer and only have a brown body. They are smaller than their counterparts, measuring roughly between 0.27 and 0.39 inches (0.70 – 1 cm).
Joro spiders can be easily observed in the spring, summer and fall, before the end of their one-year life cycle in the winter (November and December).
Joro spiders typically have a one-year life cycle and are invasive species native to Japan
They are venomous but pose no threat to humans or pets and will not bite unless they feel in danger. Their canines are also not long and sharp enough to penetrate human skin.
The Joros have about double the metabolism of the golden silk spider and a 77 percent faster heart rate, which allows them to live in the cold, unlike most spiders.
They use a “balloon flight” technique that allows them to trap air with their webs, allowing them to travel 50-100 miles. Usually Joro spiders can be found in groups and not far from forests.
They are also great stowaways when they came to the US in 2014 by holding onto cargo ships.