Invasive threat: Fire ants pose risks amid heavy rainfall in northeastern Australia

An environmental group has issued a warning about the invasive threat posed by fire ants, which have been documented forming “rafts” in floodwaters to access new territory amid heavy rain and cyclone conditions in Australia’s northeast.

Reece Pianta at the Invasive Species Council said the insects were “one of the world’s worst invasive species” and were known to be more active immediately before and after rainfall.

They can be seen joining together in buoyant clumps pulled along the current in waters in the Gold Coast region of Queensland state this month, in video footage the council shared Tuesday.

“They can form rafts and float on floodwaters and land in new locations to reestablish their colonies once the floodwaters recede,” Pianta said in a phone interview. “Quite remarkable, but also quite scary.”

The council shared the video in a call for residents in Queensland and New South Wales to be vigilant in checking their properties for fire ants and informing authorities if they find any.

Fire ants, which are native to South America, are capable of a sting that can be painful for an hour and in rare cases can cause a life-threatening allergic reaction. They often attack in a swarm of ants stinging at once, according to the National Fire Ant Eradication Program in Australia.

Multiple stings “give a sensation the body is on fire” and can leave behind itchy pustules, the program said.

The spread of fire ants is a global problem. An extensive population was discovered in Europe for the first time in September. In the United States, where they were introduced in the first half of the 20th century, they are present in Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, and Puerto Rico, as noted by the U.S. Department of Agriculture.

Fire ants were first recorded in Australia in 2001 and have steadily increased their foothold. Usually limited to the tropical state of Queensland, they were detected further south in northern New South Wales for the first time in November.

“We have enough stinging things in Australia,” Pianta said. “We don’t want another one.” The ants’ mode of entry into Australia is not certain but was probably through shipping containers from the United States, according to the National Fire Ant Eradication Program.

Australian state and federal governments have committed more than 670 million Australian dollars, or $440 million, to eradication efforts since 2017, the government reported in October.

Agriculture, Fisheries and Forestry Minister Murray Watt said then that the insects were capable of spreading across 97 percent of the country. “They have the potential to do more damage to our agriculture and environment than all of the worst invasive pests combined,” he said.