Tom's Life Bits

Wade Rawlins, Staff Writer

The name alone is enough to induce a shudder: the Asian needle ant. The tiny insect with the oversized stinger packs a painful sting and has quietly invaded Southeastern forests, scientists say.

The needle ant ranges from Georgia to New York and is now widespread in the Carolinas, researchers have discovered. They say it poses an emerging risk to public health and to native ecosystems.

“We found it in large evidence,” said Benoit Guenard, a graduate student at N.C. State University who is writing a doctoral dissertation on the ant. “We found them in every forest in the Raleigh area. People have them in the backyard.”

The ant isn't readily recognized, even by insect experts. In August 2006, Guenard was collecting insects in Umstead State Park soon after arriving at NCSU and found an unfamiliar ant. About 50 ant species are known to inhabit the Triangle.

Eventually, Guenard identified the insect as the Asian needle ant, native to Japan. It is black, slightly longer than a fire ant and more slender.

The insect was first documented by a scientist in the Carolinas in 1932 in New Bern and about the same time in Georgia. It was probably introduced into the United States through trade. Its population seems to have exploded in recent decades, scientists say, but it's unclear why.

“We are really at the level of very basic research to understand what is going on,” Guenard said.

Potential threat

Researchers at Clemson University said the insect poses an emerging threat to public health, particularly to people with strong allergic reactions to insect stings.

Patricia Zungoli, a professor of entomology at Clemson, said researchers had documented three cases in recent years of people stung by the ant experiencing anaphylactic shock – two in South Carolina and one in North Carolina.

“In all three cases, the people recovered, but only because they were close to a hospital and received medical attention immediately,” Zungoli said. “My guess is there are more cases out there than are documented, and they are just being attributed to fire ants. When people are stung by an ant, they just assume it's a fire ant.”

Eeeeeyowch!

“It's quite a whopper of a stinger,” she said.

Still, there's no reason to panic. The needle ant is quite timid and its instinct is to hide or flee. It stings only as a last resort, such as if it gets trapped in clothing, researchers say.

“These are not aggressive ants,” Zungoli said. “They do not attack in unison the way fire ants will. When you're stung, you're usually stung by one insect.”

Researchers have found that where the needle ant establishes itself in forests, it typically displaces most native ant species. They don't understand why.

The ant community helps keep the ecosystem in balance and controls populations of other insects, keeping them from becoming pests. Native ants also serve a Johnny Appleseed role, dispersing the seeds of many forest plants.

“When you get something like the Asian needle ant that displaces those species, you begin to upset that balance,” Zungoli said. “What will happen we don't know.”

In urban areas, the ants nest under stones, pavers, logs, stumps and debris. They eat termites and are often found in termite nests.

Rob Dunn, an assistant professor of biology at N.C. State, said it's best to take precautions to avoid getting stung. But Dunn said, at this point, the needle ants pose more of a pest risk to ecosystems than to humans.

“The greater concern would be local ecological consequences,” Dunn said.

Dunn said the number of transplanted ant species is huge.

“Something about ants makes them better able to catch a ride with us and set up shop once they catch a ride,” he said.