SAN ANTONIO, Sept. 10 (UPI) -- Officials say they're concerned an invasive ant species from the Houston area may spread west to San Antonio and south to the Rio Grande Valley.

The exodus of crazy ants -- so called because they move in all directions rather than in a straight line -- is "a significant change," Rob Plowes, a research associate with the University of Texas at Austin Fire Ant Research Center, told the Fort Worth (Texas) Star-Telegram.

Until now, the ants, formally known as Paratrechina species near pubens, were limited to the Houston area, taking over homes and yards, the newspaper said.

"They can so overwhelm a yard that your dog won't even want to go outside to pee," Texas Parks and Wildlife entomologist Mike Quinn told the newspaper.

"If a pet or even a person steps outside, they can be covered in ants within a minute," he said.

The agricultural effects could be even greater, said exterminator Tom Rasberry, who discovered the ants in 2002 and was called on by NASA's Johnson Space Center in Houston last year in an attempt to keep the ants out of its facilities.

"From an ecological standpoint, when you go out into rural areas where there's an infestation, there's an eerie silence -- there's a lack of insects and grasshoppers, a lack of songbirds," Rasberry told the newspaper.

The ants also appear attracted to electrical equipment, including computers and air-conditioners, Rasberry said.

In the past two weeks "these ants shorted out computers and control valves on pipelines that cost one company a million dollars for just one incident," he said.