Deadly fire ants form ‘flood rafts’ to conquer Australia

INVADING fire ants are forming rafts to take advantage of floods in storm-ravaged Australia and colonise new territories, experts have warned.

The species, which is originally from South America, is one of the most dangerous invasive animals ever introduced to the country.

They pose a serious threat to native wildlife and agriculture and can kill people with their toxic sting.

Until now, colonies of the “super pest” have been confined to south-eastern Queensland and a small part of New South Wales but weeks of torrential rain and flooding along Australia’s eastern seaboard is allowing the ants to expand their range.

The species has been observed on sugar cane farms south of Brisbane where they were gathering in “rafts” and floating on flood water – a type of behaviour rarely seen before.

The ants, which most commonly attack the eggs and fledglings of ground-nesting birds, only forms rafts when they reach a certain population density, so the behaviour suggests the species is thriving.

“The recent heavy rainfall and wild weather in the region could accelerate the spread of fire ants, one of the world’s worst invasive species,” said Reece

Pianta, Australia’s Invasive Species Council’s advocacy manager.

“Fire ants are more active before or after rainfall and can form large floating rafts which move with water currents to establish footholds in new areas.”

Residents are being urged to report fire ant sightings in an effort to control the spread of the creatures.

“Fire ants are one of the world’s worst super pests and, if they are allowed to spread across the continent, their economic impact will be greater than cane toads, rabbits, feral cats and foxes combined,” said Mr Pianta.

“They will devastate Australia’s environment and agriculture, cost our economy billions annually and we could see more than 140,000 extra medical visits every year as they sting Australians at the park or in the back yard.”

Fire ants, which could cost Australia’s economy Aud$2billion (£1 billion) a year if they get out of control, are thought to have arrived in Queensland in contaminated soil from the United States in the late 1990s. Australia has committed up to Aud$300million a year to its 10-year eradication programme.

Fire ants are dark reddish-brown and range in length from two to six millimetres. Mature colonies are capable of holding as many as 100,000 ants each and a queen is able to lay up to 5,000 eggs per day.