An invasive species of ant from Argentina and Brazil is killing off other ant species, including the hated red fire ant, in the southern United States, University of Texas researchers say in a recent study published by the journal Biological Invasions.
“Tawny crazy ants” – official name: Nylanderia fulva – were first spotted in a Houston suburb in 2002, and have since wiped out five other ant species in areas of the Texas Gulf coast, the researchers say.
The crazy ant colonies don’t seem to have any natural enemies in the Southern states, and traditional poisons don’t kill them.
The resulting dominance of the crazy ant is erasing biodiversity at the bottom of the food chain, which will have implications for the entire ecosystem, Ed LeBrun, a researcher at the University of Texas’ invasive species research program, said.
“Perhaps the biggest deal is the displacement of the fire ant, which is the 300 pound gorilla in Texas ecosystems these days,” he explained. “The whole system has changed around fire ants. Things that can’t tolerate fire ants are gone. Many that can have flourished. New things have come in. Now we are going to go through and whack the fire ants and put something in its place that has a very different biology. There are going to be a lot of changes that come from that.”
While crazy ants don’t sting like fire ants, they’re still bothersome to humans.
"When you talk to folks who live in the invaded areas, they tell you they want their fire ants back," LeBrun said. "Fire ants are in many ways very polite. They live in your yard. They form mounds and stay there, and they only interact with you if you step on their mound."
In contrast, crazy ants build mega-colonies inside people’s houses and even nest in appliances and houseplants.
"There are videos on YouTube of people sweeping out dustpans full of these ants from their bathroom,” LeBrun said. “You have to call pest control operators every three or four months just to keep the infestation under control. It's very expensive."
So far, crazy ants have taken up residence in 21 counties in Texas, 20 counties in Florida, and a few sites in southern Mississippi and southern Louisiana.