Asian needle ants have reached New England. This is what to learn about them.

Local News

These invasive ants may look harmless, but they deliver a potentially deadly sting.

The invasive Asian needle ant appears to have spread as far north as Massachusetts, bringing with it concerns over their painful — and potentially dangerous — sting.  

According to Scientific American, the ants have been identified in Massachusetts, Rhode Island, and Connecticut, having spread east across the United States. 

The sting of an Asian needle ant may cause a severe allergic reaction, or anaphylaxis, in about 2 percent of people, according to the U.S. Forest Service.  In most cases, the sting causes intense pain that can come and go over the course of several hours. Redness of the skin and mild to severe hives are also possible symptoms, according to the service.

“If you suspect you are having a systemic allergic reaction (anaphylaxis) from an Asian needle ant sting, seek immediate medical attention as it could be life-threatening,” the Forest Service said in its 2021 announcement.

The ants’ presence is being tracked by antmaps.org, which shows that the insect has been found in as many as 20 U.S. states. While the ants are mainly stretching from Arkansas to New England, outliers have also been discovered in Washington state.

Asian needle ants are small, measuring about 0.2 inches in length, according to the Forest Service. Their bodies are shiny with a dark brown to black color, though the ends of their antennae and their legs are a light orange-brown. They can be hard to identify, as they resemble other common ant species in the Eastern U.S.

The insects are native to China, Japan, and North and South Korea, though they were first documented in the southeastern U.S. in 1932. In 2021, the Forest Service announced that the invasive ant was becoming problematic in North America after remaining relatively unnoticed for decades. 

In addition to the risk of anaphylaxis, Asian needle ants also pose a risk to local ecosystems, as they decrease the population of native ants that are crucial for the dispersal of seeds, according to the Forest Service.

People can take measures to avoid being stung by paying close attention to areas with debris on the ground, such as logs, leaf litter, and rocks under which ants can nest.

“Researchers are continuing to assess the impacts of this invasive ant on people and the environment, as well as effective means of controlling it where there is a high likelihood of human encounters,” the Forest Service said. “Unfortunately, as with many invasive species, it appears Asian needle ants are here to stay.”

Morgan Rousseau is a freelance writer for Boston.com, where she reports on a variety of local and regional news.