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What we learned with the 2020 Joro Count, and how you can hear more from spider researchers
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The female Joro spider is characterized by black and yellow markings along with red on her abdomen. - photo by Scott Rogers

The spider sightings are in, and the 2020 Joro Count is over.  

From Oct. 19 through Nov. 2, The Times asked people from across Georgia to chart Joro spider encounters, along with photos on a Google map. Hundreds responded, plotting their sighting addresses and pictures to the count.  

The map has now been turned over to Mattias Johansson, assistant biology professor at the University of North Georgia, and his student research team to better measure the spider’s ecological impact on native species.  

Flaunting bright yellow and large multi-layered webs, Joro spiders are native to China, Korea, Japan and Taiwan. Johansson said they only started popping up in Northeast Georgia in 2014, and since then, their numbers have been on the rise. One female Joro spider can lay between 400-1,500 eggs in a year. 

Joro spider talk with Mattias Johansson 

What: Live webinar where people can learn about Joro spiders and ask questions 

When: Noon Friday, Nov. 13. 

Where: UNG Facebook Live 

By examining the map, Johansson said he wasn’t surprised by the dense population in Gainesville where he knew the spiders had been appearing for years. What he said did catch him off guard were the outlying reports from around Atlanta, Columbus, Savannah and southern Tennessee. 

“We expected them to spread fairly rapidly because they’re able to balloon,” Johansson said. “It’s probably more rapid than what I would expect, which is concerning.” 

Johansson said baby Joro spiders can cover a lot of ground because of their ballooning technique, which involves releasing threads of web material to catch the air current like a parachute. Once in the air, he said they can move hundreds of miles.  

“Being transported by the wind, they’re not spread out evenly,” he said. “They go in all kinds of directions.” 

So far, Johansson said he can’t say in 100% confidence that all the charted locations have Joro sightings. This is because not all of them have photo evidence. However, he said the map has ultimately proved useful in better understanding the species’ range. 

For the future, he hopes to expand the map’s reach to make it even more efficient. 

“The more people hear about this, the more reach we have,” he said. “Anything that gets more eyes on the ground is useful. They’re going to continue to spread.” 

For those who would like to learn more about Joro spiders, Johansson will be speaking on the topic at noon on Friday, Nov. 13, via Facebook Live on UNG’s social media. People will have the opportunity to interact with him and ask questions.