Watch Out for These Invasive, Stinging Ants That May Cause Life-Threatening Allergic Reactions
First introduced in the 1930s, carnivorous Asian needle ants appear to be spreading across the United States
/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/accounts/headshot/SarahKuta.png)
Experts are sounding the alarm about an invasive, carnivorous ant with a painful sting that’s spreading across the United States.
Asian needle ants (Brachyponera chinensis) were first discovered in the U.S. in 1932. However, in recent years, the insects have been surging across the southeast and expanding their range north and west, reports Live Science’s Sascha Pare. They pose a threat to anyone who spends time outdoors, but especially those who typically have bad reactions to wasp or bee stings.
Asian needle ants are not aggressive and usually skitter away when they encounter humans. However, if they can’t escape—such as if they get trapped under clothing—they’re known to deliver a powerful, venomous sting to defend themselves.
In most individuals, these stings will cause severe, localized pain that usually dissipates within hours. But for some, the venom may cause anaphylaxis, a potentially life-threatening allergic reaction that can lead to symptoms like difficulty breathing, vomiting or diarrhea, fainting and skin reactions.
Asian needle ants have stayed largely under the radar since their introduction nearly a century ago. But recently, they seem to be causing more problems. Last year, for instance, University of Georgia entomologist Dan Suiter heard from three individuals who had suffered anaphylaxis after being stung by the invasive insects—a trend that caught his attention.
“We are now considering it a medically important pest,” Suiter tells FOX Weather’s Hayley Vawter.
The ants also appear to be spreading, reports USA Today’s Elizabeth Weise. Asian needle ants were once largely contained to the southeast U.S., but they’ve recently been spotted in parts of New England and as far west as Washington state. Sightings suggest they have established populations in more than a dozen states, according to the online ant database Antmaps.org.
Asian needle ants are relatively small—roughly 0.2 inches long—and have dark, shiny bodies. Their antennae and the tips of their legs are lighter in color and have an orange-brown tint.
The species can be difficult to distinguish from other ants, but it does exhibit at least one distinctive behavior that can help set it apart. Unlike other species that create pheromone trails to lead their colony members to food sources, Asian needle ants use a technique known as “tandem carrying,” per USA Today. Rather than laying down scent trails, they will carry their fellow worker ants to food sources like termites, beetles, grasshoppers and flies.
Otherwise, they’re usually spotted meandering alone, and their path may appear random and chaotic.
“This critter kind of wanders around,” Suiter tells FOX Weather. “It looks lost.”
Asian needle ants are most active in July and August, when humans also tend to spend more time outdoors. They like to live in damp firewood and logs, as well as in leaf litter and mulch, but can also be found under rocks and in potted plants. They’ve shown up in both disturbed and natural areas, from school cafeterias and residential lawns to state and national parks, according to North Carolina State University.
“People are most often stung when they’re working in their garden,” says Theresa Dellinger, an entomologist at Virginia Tech, to USA Today. “Nobody likes to be putting in their bedding plants and then suddenly have unexpected pain.”
Cleaning up yard debris and old logs—or at least moving them up off the ground to dry them out—can help stave off Asian needle ant infestations. Wearing gloves and paying close attention while gardening can also help prevent stings. For individuals with a history of severe reactions to other types of stings, experts recommend carrying an epinephrine auto-injector.
And if you suspect you already have an infestation, experts say to call in a pest control professional, because Asian needle ants can be difficult to eradicate.
“We suggest a protein-based bait for this species, and it can take some time for these ants to take the poison back to the colony,” Dellinger tells USA Today.
Beyond the harm they can cause to humans, Asian needle ants are bad for the environment. Once they establish themselves in a new area, scientists have noticed that native ant populations tend to decline, according to the U.S. Department of Agriculture Forest Service. In particular, the invaders seem to displace ant species that help disperse plant seeds. Over longer periods, this could hurt forest ecosystems.
“Unfortunately, as with many invasive species, it appears Asian needle ants are here to stay,” according to the Forest Service.
