Sunday, February 25, 2024

Invasive fire ants continue their march across Virginia

Solenopsis invicta (California Academy of Sciences/April Nobile)

As a young boy in Connecticut, Alvin Cajigas played with harmless ants. When he was 11 and living in Puerto Rico, he came across a mound of dirt a few inches tall. He knocked the top off with a finger.

“Hundreds of ants, or thousands of ants, came swarming out,” recalled Cajigas, now in his early 50s and living in Chesterfield County.

For several seconds, Cajigas was fascinated by the rushing insects. “Then they were all over my hand and stinging me all over the place.” Each sting felt like a hot needle. “It was not pleasant.”

Cajigas’ father treated the stings with the soothing juice of a native plant. As for Cajigas, “I learned real quick not to touch those red mounds.”

Cajigas had discovered a colony of fire ants — venomous stinging insects that attack in large numbers.

Virginians are increasingly encountering fire ants right here at home. More properly called red imported fire ants, the invasive creatures are native to South America, and they have been working their way up from America’s Gulf Coast for decades. Virginia is their northernmost reach. They infest Hampton Roads, the Williamsburg area and parts of the Petersburg and Southside areas, and they’re homing in on Richmond.

“You do your best to slow it down, but at this point we can’t eradicate red imported fire ants from Virginia,” said David Gianino, a program manager in the Virginia Department of Agriculture and Consumer Services.

‘Always angry hour’

Fire ants bite, but it’s the venomous sting, sometimes delivered by dozens at a time, that’s dangerous. They attack adults, children, pets and wildlife in yards, parks and farm fields. They can kill small animals, stripping a carcass to the bone like little piranhas.  Rarely, the ants can even kill people as a result of allergic reactions to their stings.

Fire ants are highly aggressive and surprisingly fast.

“It’s never happy hour with fire ants,” said Eric Day, a Virginia Tech entomologist. “It’s always angry hour.” 

Fire ants have been expanding their Virginia territory for three decades, but the pace of that invasion quickened in recent years as the insects moved west through Southside Virginia, experts say.  

“The fire ant is a big deal for us here in the state, particularly as it’s starting to move more frequently into more rural areas,” Gianino said.

Virginia agencies and universities are fighting back by educating the public. Efforts include talks and web pages.  

“We need everybody to kind of come together and help us manage this pest,” Gianino said.

Fire ants live in extensive underground tunnels topped by earthen mounds that can be nearly flat, a few inches tall or more than 2 feet tall. 

Fire ants scamper across a newspaper after swarming from a mound on April 4, 2022, in Suffolk. The venomous ants have stepped up their invasion of Virginia. (Photo by Rex Springston/Special to the Virginia Mercury)

The ants get their name from their sting, which burns like fire. The tiny insects are red-ish, with black, bulbous butts — gasters, to be precise. 

Nearly a century ago, a cargo ship unwittingly carried fire ants from South America to an Alabama port. From there, they spread across the South, to Texas and Florida and north to Virginia, reaching a Hampton golf course in 1989. A few years later, they were infesting much of southeastern Virginia. 

By 2009 fire ants were so thick in that region that the state created an 11-locality quarantine zone to slow their spread. The zone ran from Virginia Beach west to Suffolk and north to James City County. In 2019 the quarantine zone added seven localities to the west — the cities of Franklin and Emporia and five counties from Isle of Wight to Mecklenburg.

A map from Virginia Tech, released last month, shows the ants are now infesting five more southern counties — Sussex, Dinwiddie, Lunenburg, Charlotte and Halifax. Those largely rural counties “have multiple mounds at multiple sites,” Gianino said.

“Fire ants are all over the North Carolina-Virginia border in the Lake Gaston area,” said Mary Elko-Kelly, who lives in North Carolina just below Virginia’s Mecklenburg County. “We never had them until, I’d say, the last three or four years. Now they are everywhere, and their sting hurts…They are nasty little creatures.”

For the record, I found about a half-dozen fire ant mounds in early April on the farm of my father-in-law, Steve Butler, on the Suffolk-Isle of Wight line. I had learned to recognize the mounds during explorations of South Carolina and Florida. My wife has been stung.

Now at least 20 mounds dot the Butler farm. I don’t know if new mounds are popping up or if family members are just looking harder. Butler is following experts’ suggestions and treating the mounds with fire-ant-specific insecticides. 

This rapid invasion pushed me to learn more.

‘They have gone beyond where they were expected to’

As localities become infested with fire ants, the ants create more mounds that produce more ants that can create even more mounds and more ants in an accelerating momentum. 

Warm weather in recent years, possibly assisted by climate change, seems to have helped the tropical insects invade Virginia. At first, Virginia Tech’s Day said, scientists thought the ants wouldn’t thrive beyond the warmth of southeastern Virginia. “My experience is they have gone beyond where they were expected to go 30 years ago.”

Fire ants cost Americans more than $6 billion a year in medical care, damage and control, according to federal officials.

A fire ant grabs you with its mandibles, or mouth parts, then injects venom from a stinger on its tail. The stings are almost always painful, but some people suffer worse reactions than others. A sting can leave a white, fluid-filled bump that will dry out and itch for weeks. Stings can leave scars.

Fire ants rarely kill people, but some people are highly allergic to their venom. A Virginia Beach landscaper died after an attack in 2006. 

You can treat most stings with over-the-counter pain relievers. If your reaction is severe, go right to a doctor.

Fire ants eat almost anything — other insects, plants, small animals, hot dogs, even ticks and termites. Experts say the ants’ stings can injure pets, blind calves and cause infections that can kill young farm animals.   

Bryan Watts, a College of William and Mary ornithologist, was studying rare sparrows in South Carolina a few years ago when a couple of the birds’ nests were found by an ant mound. “The young were covered (by ants) and consumed,” Watts said. “Not a pleasant way to go.”

“In some areas now, fire ants can be one of the leading causes of nest failure for some ground-nesting species,” Watts said.

Fire ants have turned up a few times in the Richmond area, but state workers were able to exterminate them. The big question is: How far north can the ants, aided by climate change, move and thrive before they are stopped by winters that are too cold? 

“We are really kind of learning and figuring out how far this ant will spread into Virginia,” Day said.

This fire ant mound in western Suffolk appeared to be 2 feet long or more. The photo was taken after the mound was discovered May 12, 2022. Venomous fire ants can kill small animals and, rarely, people. (Photo by Rex Springston/ Special to the Virginia Mercury)

Living with fire ants

A federal map projects that fire ants will eventually find excellent homes in roughly the eastern third of Virginia and a large chunk of Southside.

“I do expect them eventually to get here” in the Richmond area, Gianino said. He doesn’t see the ants moving into cooler Northern Virginia or the mountains anytime soon.

Virginia has more than 160 ant species. The vast majority are harmless to people.

In fire ant land, females rule. A typical colony consists of a single queen, a few hundred thousand worker ants — all female — and smaller numbers of winged males and females that can reproduce.  

Fire ants colonize new lands in two main ways — naturally, by flying from their mounds, and accidentally, aboard nursery shipments, logging equipment and the like.

Over the next few weeks in Virginia, those winged ants will burst into the air to mate. After these “nuptial flights,” the males — having done their one job in life — will fall to the ground and die. Most of the females will die, too — from exposure, or in the mouths of birds and other predators. But enough will live to lay eggs and start new colonies.

The ants can also invade by water. That could help them move through coastal Virginia, where global warming is pushing up sea levels and causing increased flooding.

“One of the things these ants can do really well is they can raft,” Gianino said. “They grab ahold to each other in a large group and float on top of water…It’s something wild to see.”

Fire ants in Virginia have been a problem mainly in places like yards and parks. But now that they infest parts of largely agricultural Southside, they pose increasing threats to farmers and loggers, too. “It’s a worker safety issue,” Day said.

Equipment leaving the quarantine zone must undergo inspections.

So what can we do?

If you find a fire-ant mound outside the quarantine zone, state workers will treat it with ant-killing baits for free. You can report mounds at .

Inside the quarantine area, however, the mounds are so numerous that the state won’t tackle them. You are on your own. You can hire an exterminator or buy the insecticide-laced baits at the hardware store. Local extension agents can offer advice.

In those rural, infested counties outside the quarantine area, the state is hindered in its response. Federal environmental rules prohibit the use of the ant-killing baits in farm fields and pastures, to prevent exposing livestock or the public’s food to insecticides. That means state workers can kill colonies outside fields, but a lot of ant mounds remain free to pump out new queens.

If Virginia can’t hold the ants at bay in those five counties, the localities will probably be added to the quarantine zone, state officials say.

The South is not alone in fire-ant misery. The creature has spread to more than 20 countries and territories, including China, Taiwan and, of course, Alvin Cajigas’ former home, Puerto Rico.

The fire ant’s scientific name, by the way, is Solenopsis invicta. In Latin, “invicta” means “unconquered”.

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