Invasive Joro spiders are weaving their web across the US: What to know about the arachnid
According to new research, the massive invasive Joro spiders are spreading throughout the U.S. and are not likely to go away anytime soon.
They were first spotted in the U.S. in Georgia from 2013 to 2014, and their population has flourished since then throughout the state and in other parts of the Southeast.
Researchers at Clemson University published a study on Joro spiders, concluding that the species is spreading rapidly beyond South Carolina, and data shows they could inhabit most of the eastern U.S.
Here's what we know of Joro spiders:
How big is the Joro spider?
Joro spiders belong to a large spider species known as golden silk orb-weavers. They spin oversized webs of gold-colored silk, which is similar to the U.S. native golden silk spider, also known as the banana spider, found in the Southeast.
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Adult females have legs about 3 inches long, which gives them a span of 6 to 8 inches if their legs are extended.
The female Joro spiders are huge, as big as your palm, but don't let their size scare you. They're venomous but shy, and they don't pose a threat to people because their venom is weak and their tiny fangs can't easily pierce human skin.
Hudson said the female's abdomen will usually be full of eggs, so it will be about the size of your thumb. Underneath, the spider has a black and gold checkerboard pattern with red splotches.
What do Joro spiders eat?
Joros eat bees and the usual garden pests, such as ants, flies, mosquitoes and stink bugs. Larger Orb-web Weavers spiders have been known to prey on other creatures, such as centipedes, lizards and even small birds like hummingbirds, which can be trapped in their webs.
Joro spiders don't appear to cause problems in the local food sources of other animals or local ecosystems, Hudson said. They may even be a food source for birds.
Is the Joro spider poisonous?
The spiders secrete venom, but they don't bite unless they're cornered. Their bites are similar to bee stings and could produce localized pain and redness around the bite area.
Where did Joro spiders come from?
Joro spiders are native to Asia. They prefer tropical and subtropical regions of the world.
Where are Joro spiders in the US now?
There is no clear answer for how Joros came to the U.S., though they probably arrived in shipping containers. In nearly 10 years, the species has rapidly spread across Georgia and other parts of the Southeast.
According to iNaturalist.org Joro spiders reside mainly in Georgia but have migrated to neighboring states. They've been spotted in South Carolina, North Carolina and Tennessee, with reports of the spider in Alabama, Oklahoma, West Virginia and Maryland.
David Coyle, a scientist and professor at Clemson, had one major takeaway from the results of the study: "These things are here to stay."
The Joro spider’s relative, the golden silk spider, inhabits much of the Southeast and hasn’t migrated north because of the colder temperatures. The golden silk spider has been in the U.S. for about 160 years.
Research from the University of Georgia shows that Joro spiders can withstand freezing conditions far better than golden silk spiders. They have a higher metabolism and heart rate that lets them withstand chilly climates. That may allow them to spread to colder regions in the states.
How to identify a Joro spider's web
Orb-weaving spiders like the Joro spin five types of fibrous silks from their glands to make elaborate webs and silk egg sacs. Their web silk is strong, stretchy and coated with a watery glue-like substance that allows them to catch their prey easily.
Typically, Joro webs are 3 to 9 feet in diameter. They can be found near the edge of forests, parks and streams of water. Webs are generally 6 to 10 feet above the ground. Many have been found near the exteriors of homes.
Life cycle of the Joro spider
Male Joro spiders must carefully pursue females or they may become their mate's next meal. Some male spiders wait until the female is already eating to make their approach, according to Paul Guillebeau, professor of entomology at the University of Georgia.
Life cycles for the female Joro end in late fall to early winter. The next generation emerges in the spring. Research has shown Joro spiders have a short life cycle.
Do Joro spiders fly?
When Joro hatchlings emerge in spring, they ride the winds using their silk as a balloon, just like in the animated movie "Charlotte's Web." Most web spiders do some form of ballooning, but the Joro spider will leave from an elevated spot. If its silk gets long enough, winds can carry it 100 miles or more.
CONTRIBUTING Jordan Mendoza, Jay Cannon and Emily DeLatter, Paste BN