Georgia Gwinnett College discovers bacteria in Joro spider

Ten years ago, Joro spiders traveled from Asia to the U.S. Georgia is where they were first spotted. What scientists know is they are most visible starting in September. By mid-October, they are laying eggs that are within a white silk sac. Each sac, typically attached to a flat surface like leaves and tree bark, contains as many as 500 eggs.

What hasn't been known is if they carry any diseases that could harm humans.

Georgia Gwinnett College's professor of biology, Dr. James Russell, was studying the genetic makeup of the Joro spider to determine if there was any genetic diversification. Along with a GGC student, Nicholas Mizera, the pair took on the task of extracting genes from the spiders.

"There was very little genetic diversity, so on a whim, we decided to look for the presence of Wolbachia," he said. "It's a common bacteria found in about half of all insect species, like butterflies, moths and bees. We found that Joro spiders are infected with Wolbachia."

Russell added that two questions would be the first to ask.

"One, can Joro spiders transmit Wolbachia to humans? The answer is no," he said.

The second question has to do with how Wolbachia affects Joro spiders.

"We hypothesize it creates reproductive barriers and incompatibility issues for the spider, but more detailed experiments are needed to test that hypothesis" he said.

According to this hypothesis, when an infected male mates with an uninfected female, the female is sterilized. However, he added, when both the male and female are infected, they can have offspring. Russell further explained that only female spiders can pass the bacteria along.

"This particular Wolbachia effect can potentially be used to control populations," he said.

The idea of population control, he said, could be applied to other insects, like mosquitos, which are known to carry diseases that can infect humans.

"Having this information could help us find a better and less harmful way to control insects that are known to harm humans," he said.

For Mizera, who graduated from GGC in 2023, the chance to do research assured him that a career in biology was the right path.

"When Dr. Russell approached me to do actual research, I loved everything about it," he said. "The work was meaningful, and that's something I want to continue doing while I pursue my doctorate."

Russell and Mizera are working on a paper to present their findings.

"One thing about research is a spirit of discovery and collaboration," he said. "Along with my colleague, Dr. Chris Brown, professor of biology, we had researchers from Clemson University, the University of Georgia and Columbus State University assist with the gathering of spiders. Our job was then to extract genes from the spiders so we could study the genetic makeup."

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