GATESVILLE — The little brown ants seen running crazy in Coryell County may be part of an exotic invasive species — tawny crazy ants — spreading inland from the Gulf Coast. Or they may just be native ants acting crazy.

“There have not been any documented cases of the tawny crazy ant in Coryell County,” said Sonja Swiger, an entomologist with the Texas A&M AgriLife Extension Service.

The reddish brown ants, about an eighth of an inch long, get their reputation for craziness by their rapid, random and erratic foraging.

The species originated in South America and was spotted in Harris County in 2002. The insects have since been verified in 27 Texas counties — Bexar, Brazoria, Brazos, Comal, Cameron, Fayette, Fort Bend, Chambers, Galveston, Hardin, Harris, Hays, Hidalgo, Jefferson, Jim Hogg, Liberty, Matagorda, Montgomery, Nueces, Polk, Orange, San Augustine, Travis, Victoria, Walker, Wharton and Williamson.

“This ant has the potential to spread well beyond the current range in coastal Texas,” according to the Texas A&M urban entomology website.

This ant is so crazy, Swiger said, that it scares away the fearsome fire ant.

“It is displacing the fire ant,” she said. “The fire ants leave when they show up.”

The tawny crazy ant does not sting, she said, but out-competes other ants for food, displacing any ant species in the neighborhood.

“The red harvester ant is not much competition” for the crazy newcomer, Swiger said.

In large infested areas, indoors and out, the crazy ants can be a nuisance to humans, pets and wildlife such as songbirds. The ants crawl into electrical outlets and can chew through the insulation on electrical wiring of tractors and other vehicles, Swiger said.

The tawny crazy ant is difficult to control or eradicate, she said. Chemicals that are effective on the species are “highly restricted” and require a commercial applicator license.

Not every crazy little brown ant belongs to this exotic species, Swiger said. “There are some native crazy ants that are similar but noninvasive,” she said.

Anyone who thinks they may have tawny crazy ants on their property is encouraged to collect some of the insects and mail them to Swiger for identification.

Put the ants in a sealed container, such as a plastic bag, and mail to Sonja Swiger, 1229 North U.S. Highway 281, Stephenville, TX 76401.

“I will look at them under a microscope,” she said. If she can’t identify them, she said she will send them to a tawny crazy ant expert in College Station.

“We are hoping they are not in Central Texas,” she said.

Contact Tim Orwig at

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