Red imported fire ant invasions around the globe in recent years can now be traced to the southern U.S., where the nuisance insect gained a foothold in the 1930s, new University of Florida research has found.

Native to South America, the ant had been contained there and in the Southeastern U.S. before turning up in faraway places in the last 20 years — including California, China, Taiwan, Australia and New Zealand.

The study in a recent edition of Sciencewas co-authored by Marina Ascunce, a postdoctoral associate with the Florida Museum of Natural History on the UF campus and Chin-Cheng Yang of National Taiwan University.

The team’s findings could prove helpful in finding new ways to control the invasive species, Solenopsis invicta, Ascunce said. Americans spend more than $6 billion a year to control the ants and offset damage they cause, including medical expenses and $750 million in agricultural losses.

“Fire ants are very annoying pests, and they cause people to suffer,” Ascunce said. “People who are allergic can die (from ant stings).”

Red imported fire ants are highly aggressive. They have a painful sting, often discovered by humans only after stepping on a mound.

The research team used several types of molecular genetic markers to trace the origins of ants in nine locations where recent invasions occurred. They traced all but one of the invasions to the southern U.S. The exception was an instance where the ants moved from the southeastern U.S. to California, then to Taiwan.