Listed in the top 100 of the “World’s Worst Invaders” these ants probably came to the U.S. on cargo ships and now pose a danger to Florida’s native insects.
Amanda Inscore, AINSCORE@NEWS-PRESS.COM
FORT MYERS, Fla. – Step aside, fire ants. There’s a new six-legged sheriff in town.
For the last few decades, bigheaded ants have been quietly outcompeting the dreaded South American invaders in Southwest Florida.
And while that’s bad news for native species, it’s less bad news for the humans who live and walk near their nests: Bigheaded ants’ stingers are too small to penetrate people’s skin the way fire ants do, leaving their victims pocked with ferociously itchy pustules.
But it’s definitely not good news either. “Oh, they’re bad news,” said University of Florida entomologist Phil Koehler. “Nasty critters.”
Bigheaded ants reproduce prodigiously. Their cities can stretch for whole blocks, and can take months of coordinated effort to remove.
“They are what’s called a supercolony,” said ant expert Mike Ryan of Tempco Pest Control in Fort Myers.
“The population is so huge, they will actually force fire ants off your property,” Ryan said. “They’re so aggressive that no other ant can compete against them.”
Originally from the Indian Ocean island of Mauritius, bigheaded ants likely arrived in Florida on freight ships, docking in Miami and the Keys in the early part of the 20th century, Ryan said. In recent years, though, hurricanes have helped disperse them to the west, plus, “We bring a lot of plant material from Homestead and the Miami area to our coast,” he said.
Biologists consider bigheaded ants to be one of the most pernicious invasive species in terms of the threat they pose to native insects, thereby disrupting the local ecology.
They can damage lawns and kill trees, and they also can come into homes seeking food, Ryan said.
“They can dig down 10 or 12 feet,” he said, “They can actually dig under the foundation. The nest can be underneath your house and they can actually come in from the plumbing inside your kitchens and bathrooms.”
Once inside, they eat almost anything, but prefer proteins and fats.
Their name aside, not all bigheaded ants have large heads. Those that do are female “major workers” — the colony’s soldiers. The smaller ones, also females, gather food.
“The males are usually transient and you don’t find them all the time,” said University of Florida research scientist Roberto Pereira, who specializes in urban entomology. “Males are basically useless. In the ant world, the males don’t do any work, except mate with future queens.”
Once she’s inseminated, the queen begins to lay eggs.
“Their mounds actually look fairly similar to the fire ant mounds,” Pereira said “but they’re not as high and not as compact.”
One of the challenges of getting rid of bigheaded ants is “If you spray them, they bud, which means they split the colony,“ Ryan said. “So instead of one colony you’re dealing with multiple, multiple colonies … They’ll take over communities. We’re dealing with a community down in Bonita, where that’s what’s happening to the whole community. They’re just taking over.”
So what can be done to remove them? Capitalize on their sociability, Ryan said. “Because they share food, what you want to do is feed a product to the ants so they bring it back and feed their friends and then there’s this massive killing that happens.”
One thing homeowners should do, Ryan said, is keep vegetation trimmed back so it doesn’t touch the house.
“You don’t want an archway from the ground to your house,” he said.
But if they do show up, do-it-yourself control is a long shot.
“Literally, if you have them, you almost have to call a professional because they have to treat the whole inside of the house and then they’re going to have to spray or bait and treat the outside of the house. It’s a very intensive program.”
Costs will vary from company to company, but will be somewhere around $75 every two months.
“It’s important to try to get your neighbors to do it. One thing, if you treat your house, you can actually push the ants to your neighbor’s house. So if you don’t like your neighbors, you know … ” Ryan said with a chuckle.
Follow Amy Bennett Williams on Twitter: @AmySWFL
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