Fire ants could sting 8.6 million Australians a year if they were to become endemic – but a pathogenic fungus and pesticide-loaded drones might help avert that scenario, according to submissions posed to the federal government’s fire ants inquiry.
Submissions to the Senate inquiry into red imported fire ants (Rifa) in Australia closed on Monday, just days after the latest in a string of fire ant detections beyond south-east Queensland, where an infestation of the invasive pest is ongoing.
Last week a single fire ant was found in an Australia Post package of plant material sent to Tasmania from Queensland. The non-reproductive female was detected by Biosecurity Tasmania as part of “business-as-usual surveillance operations at mail centres across the state”.
In late January a fire ant nest was found in Wardell in northern New South Wales, while five nests were discovered in Murwillumbah, 13km south of the Queensland border, in November. It was the first time fire ants had crossed the Queensland border into NSW since the infestation began in 2001.
The fire ants’ march south has prompted a range of government, agricultural, health and research bodies and individuals to use the inquiry to call for resources and education to help stamp out the pest. Fire ant stings can cause anaphylaxis and death in humans. They can also damage electrical and agricultural equipment, kill native plants and damage ecosystems beyond repair.
In a joint submission to the rural and regional affairs and transport references committee, the National Allergy Centre of Excellence and Allergy and Anaphylaxis Australia predicted that if fire ants were to become endemic, a quarter of the 8.6 million Australians who would be stung by fire ants each year would develop an allergic reaction, with 174,000 of those requiring medical attention.
Up to 652,000 people a year would seek medical consultation because of Rifa stings, they said.
The Australasian Society of Clinical Immunology and Allergy said “anaphylaxis is almost three times more common with Rifa stings than with other stinging insects”.
In 2021 927 people were hospitalised after a bee sting and there were 12 deaths from wasps and bees, with 1% of bee stings causing anaphylaxis. That figure rises to 2.8% for fire ant stings, according to the society.
“Therefore, if Rifa became endemic in Australia it is likely that hospitalisations and deaths due to stinging insects would significantly increase,” it said.
The Commonwealth Scientific and Industrial Research Organisation told the committee that it was developing RNA-interference management tools that target fire ants, silencing their genes to kill or reduce reproductive potential. It is proposing laboratory-based risk assessments of a pathogenic microsporidium, or fungus, and a virus capable of killing entire fire ant colonies.
It is also researching the use of drones for biosecurity, including for the application of fire ant pesticide.
Dr Anthony Young, a senior lecturer in crop protection at the University of Queensland, described what he called the “failures” of the national red imported fire ant eradication program after a fire ant nest was detected and reported in Karana Downs, Queensland.
It took a week for an eradication team to arrive at the property, only for the owner to watch “in amazement as magpies swooped down” to eat baited maize that was intended to kill the ant colony, he said.
Last year state, territory and federal governments committed $593m to the national fire ant eradication program. A 2021 review said eradication would cost $2bn – equalling a single year of financial impacts should a nationwide infestation take hold.
Reece Pianta from the Invasive Species Council said its submission, which is one of a number yet to be published by the Senate committee, called for research into the health and environmental impacts of fire ants with a view to preparedness to protect sensitive environmental areas from invasion.
He said the council echoed Brisbane city council’s submission which detailed suppression work within the Queensland containment zone, where the public is encouraged to self-treat their properties with free bait.
“It’s not a full eradication effort but it is a good measure to keep the population slow while eradication is rolled out,” he said. “And it’s cost-effective.”
He added that last week’s Tasmania detection was “low-risk but alarming”, indicating that the ants “have got to such a high density in Queensland that they are being found in household packages in a sorting centre”.
