Are Joro Spiders Good? Are They A Helpful Invasive Species?

Written by Cindy Rasmussen
Updated: October 11, 2022
© Seve Sivathas/
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As spring seasons approach, citizens in Georgia get ready for thousands of Joro spiders to hatch and take flight. The Joro spiders are an invasive species from Japan and spread quickly throughout Georgia and into South Carolina. Scientists predict that they may be moving north along the East Coast, spreading by a technique called ballooning.

Joro spiders climb to the highest point, spin a tread of silk-like parachute and take off into the wind. This is one way they ensure their survival by starting new colonies in new locations. Should people along the Coast be concerned? Are these spiders poisonous? Do they destroy gardens? Do they carry diseases? Could they actually be a helpful species? Let’s find out!

What’s All The News About Joro Spiders?

Joro Spider Webs
Giant golden webs showed up in Georgia with large colorful spiders in them. They were later identified as the Joro spider from Japan.

© Lee

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Joro spiders are native to Japan and East Asia. Before 2014, there were no Joro spiders in the United States. But in 2014, people in Georgia came out to their gardens and noticed large golden webs with large colorful spiders. Researchers started taking DNA samples and discovered that this was a new species in the United States and identified it as the Joro Spider. There is always a concern if a new species will damage the ecosystem and how it will affect the plants, animals, and humans in the new environment.

What Are Joro Spiders?

Joro Spider in Web
Joro spiders have a leg span of 3-4 inches! Their bodies are colorful with yellow and red markings.

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Joro spiders are large colorful spiders with a leg span of 3-4 inches. Some refer to them as palm size, but their bodies are closer to the size of a quarter, measuring up to an inch long. With their legs spread out, they would cover a person’s hand. Their backs are black, with yellow stripes and a red marking. The red marking is found on their underside as well. They have long, skinny legs that are striped with alternating yellow and blue bands. The females are the ones that draw all the attention, with the males being quite smaller at a quarter-inch. Also, the males lack bright colors and are a mix of brown markings.

What Is An Example Of A Harmful Invasive Species In The US?

Wild boars are a harmful invasive species in the United States. Large herds trample crops and eat everything in their path.

©Entheta / Creative Commons

Some invasive species like wild boars wreak havoc on the environment. They cause economic problems when herds run through fields of crops, trampling and eating everything in their path. Wild boars (sometimes called feral pigs) kill off livestock like calves and lambs. They cause millions of dollars in damage across the United States. They also kill threatened and endangered species, preying on the nests of endangered birds like the prairie chicken and eliminating plants like Mead’s milkweed. Lastly, they are dangerous to humans by carrying diseases.

Are Joro Spiders An Invasive Species?

Yes and no. First, we need to define an invasive species. The term invasive is commonly used to define animals, plants, insects, etc., that weren’t in a particular place before. They are new to the environment or area. But the technical definition, according to the USDA, is that they have to be new to the environment and harmful. The USDA site states that an invasive species is one “whose introduction causes or is likely to cause economic or environmental harm or harm to human health.” We know Joro spiders are new to the environment in the United States but are they harmful?

Are Joro Spiders Bad?

No, Joro spiders are not bad. They may be new to the United States, but they do not seem harmful.

  • Economic problems?: So far, Joro spiders do not seem to be causing any damage to crops, livestock or gardens. They have not had a negative economic effect.
  • Environmental problems?: Joro spiders do not seem to compete with other established species. They have a different diet than the orb weaving spiders, so that does not seem to be an issue.
  • Harm to human health?: Joro spiders are not harmful to humans. They are venomous, but their fangs are too small to break through human skin. If they can’t break the skin, they are unable to pass on diseases.

Are Joro Spiders Good?

Mosquito sucking blood on human skin.
Mosquitoes are a diet for Joro spiders. That is a huge benefit.


Yes, Joro spiders are good. There are several ways they are beneficial. Here are three benefits of the Joro spider:

  1. Joro spiders eat mosquitoes: This should be enough right there! Forget about Citronella candles or a can of “OFF!”, all you need is a few webs of Joro spiders. Their webs are exceedingly wide with some reaching 10 feet. You can imagine how many mosquitoes could get caught in a web that size.
  2. Joro spiders eat other pests like stink bugs and aphids that harm our gardens: This makes them the best natural pesticide. There are not a lot of natural predators of aphids and stink buds, so they are filling a niche that is helpful to our gardens.
  3. Joro spiders are a new food source for birds and the mud dauber wasp: Sometimes, invasive species get out of control because there are no natural predators in their new ecosystem. There are a few animals that have added Joro spiders to their diet, including the mud dauber wasp. Did you know that mud daubers are a beneficial species because they kill black widow spiders? This is a win win for everyone!

Can I Get Joro Spiders For My Garden?

If you live along the East Coast, you might be lucky enough to have them in your town soon. They seem to be spreading quickly with their ballooning transportation and are also moving westward. There have been colonies found in South Carolina in Blairsville, Georgia, and Greenville. So, Alabama may be the next lucky state to have this natural pesticide “invade.”

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The Featured Image

Joro Spider Webs
A Joro spider and its web in the woods. These spiders, like your typical orb-weaver spider, eat various insects like mosquitoes, biting flies, and even brown marmorated stink bugs!
© Seve Sivathas/

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About the Author

I'm a Wildlife Conservation Author and Journalist, raising awareness about conservation by teaching others about the amazing animals we share the planet with. I graduated from the University of Minnesota-Morris with a degree in Elementary Education and I am a former teacher. When I am not writing I love going to my kids' soccer games, watching movies, taking on DIY projects and running with our giant Labradoodle "Tango".

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