Fire ants have been found in New South Wales. The invasive species can kill people and livestock, and damage infrastructure and ecosystems. Eradication requires a $2bn commitment – but experts warn those costs pale in comparison to the impacts of a nationwide infestation.
What are fire ants and why are they marching?
Solenopsis invicta, the red imported fire ant (Rifa), is an extremely invasive species of fire ant, so called because of its powerful sting. They are particularly good at spreading and are well adapted to parts of Australia which are similar to their native environment in the Pantanal in South America. They can survive underground for years, then form rafts in floods, travelling to colonise new ground. They have moved around the world in infested soil attached to containers and shipments.
What do Rifa look like?
Ranging from 2mm to 6mm in size, individuals are copper brown in colour with darker abdomens. Their nests look like small mounds of loose, crumbly dirt and are most often in direct sunlight on lawns, near concrete paths, taps and bodies of water, or along fence lines. To check the identity of a suspected nest, the Queensland government says to gently poke the mound with a long stick and then check the ants “erupting” from the disturbed soil.
How are they killed?
Usually by bait, which is put down and then taken into nests by the highly efficient foraging ants. An alternative is direct nest injection using the chemical found in dogs’ flea collars.
What will a fire ant do to me?
When a nest is disturbed, the ants swarm and a pheromone triggers simultaneous stinging en masse. One sting is similar to a bull ant bite, but in high numbers, stings can overwhelm victims. Anaphylaxis and secondary infections can cause death. A 2008 World Health Organization study estimated that 30-60% of people living in infested areas are stung each year, while a 2021 Taiwanese study found that 2.8% of sting victims exhibited anaphylactic shock. Rifa have caused about 85 deaths in the US, including a 43-year-old Georgia woman who died after stepping on a nest in June and an 87-year-old woman who died after being stung 1,625 times in 2000. Pets, livestock and native animals are also vulnerable.
How else can they affect us?
They can damage electrical and agricultural equipment, kill native plants and damage ecosystems beyond repair. Soil displacement damages infrastructure, in turn exposing workers. A 2021 report for Biosecurity Queensland found Rifa could cut agricultural output by up to 40%.
Without proper management, Rifa “will surpass the combined effects of many of the pests we currently regard as Australia’s worst invasive animals (rabbits, cane toads, foxes, camels, wild dogs and feral cats),” stated a 2016 independent review of the eradication program.
If they get out of control, fire ants will cost the Australian economy $1.2bn to $2bn a year according to the Biosecurity Queensland report – although some economists have told Jack Gough of the Invasive Species Council that they believe the figure to be an underestimation.
“Red imported fire ants are a terrible invasive pest, which cause serious social, economic, and environmental harm,” the NSW agriculture minister, Tara Moriarty, said.
When did they arrive in Australia?
Fire ants were first detected at the Port of Brisbane in 2001, but they may have been present since about 1992, according to a 2021 strategic review of the national Rifa response. They have infested about 700,000 hectares of south-east Queensland. Seven other incursions – all linked to ports and airports – including in Gladstone, the Port of Botany and the Port of Fremantle, have been eradicated.
On Friday, five Rifa nests were detected by a member of the public 13km south of the Queensland border on council land in South Murwillumbah in NSW, prompting a biosecurity response and urgent calls for biosecurity funding.
What does that response look like?
“We’ve had plans in place for this scenario for many months,” Moriarty told Guardian Australia. The detection triggered the National Fire Ant Eradication Program response. A Queensland government team – as the fire ant hotspot, that state leads the response – “chemically eradicated” the infestation to a radius of 200 metres from the nests.
NSW’s Department of Primary Industries implemented an emergency biosecurity order across all residents and businesses within a 5km radius of the site. Within that area, the movement of mulch, woodchips, compost, sand, gravel, soil, hay and other baled products is restricted. Breaching the biosecurity order can lead to a $1.1m fine for individuals or $2.2m for businesses. The ants are being genetically tested and all 13 properties within the zone are being searched for signs of infestation with the help of detection dogs.
Moriarty said the ants most likely travelled to NSW in a delivery of turf. Other turf shipments from the same provider are being investigated. The nests had been active for at least three months.
Is it possible there are more infestations than we know about?
Definitely. “Undiscovered nests are a huge worry,” said Reece Pianta, conservation officer at the Invasive Species Council. Surveillance depends upon members of the public notifying authorities.
How much is it costing to fight the fire ant?
Between 2001 and 2022, commonwealth and state governments spent $644m in their attempts to eradicate the pests. The National Fire Ant Eradication Program, which spans state, territory and federal governments, was devised in 2015 and funded with $411m in 2017. It was put into place in 2018 and was then the subject of 2021’s strategic review, the full recommendations of which are not likely to take effect until 2024, Gough said. A second portion of funding to cover 2023 to 2027 totals $593m, $140m of which is pending – Queensland, NSW and the federal government have funded their portions of the program thus far, “which is pretty slow when you consider how fast a fire ant colony can move”, Pianta said.
In July, a Queensland Audit Office report determined that delayed funding had likely contributed to the spread. The federal agriculture minister, Murray Watt, said Canberra had fixed a large shortfall left by the former Coalition government by bringing forward existing funding to bolster the national response. He added that there had been no delay in rolling out the program.
Is the response working?
We haven’t seen the full impact of fire ants here, thanks to 22 years of containment efforts – efforts that, until now, kept the ants from spreading over state borders. The program has so far failed in its objective of eradication.
The 2021 strategic review concluded that the program could not eradicate or contain fire ants within the scope and budget of the 10-year plan. Despite this year’s additional $593m, the Invasive Species Council does not believe the funding goes far enough: not only has the size of the affected area increased, but inflation makes the cost of imported baits more expensive. Their concerns are echoed by the NSW Farmers Association and the NSW Nationals.
“Eradication is possible, but as time goes by, the cost goes up. We’re better off spending more earlier to prevent a bigger cost down the track,” Pianta said. The review stated that eradication would cost $2bn – equalling a single year of financial impacts should a nationwide infestation take hold. “Is there a cost benefit to not adapting and trying to solve it? Yes, and while there is, we need to take that opportunity,” he said.
Might the fire ant become the next cane toad?
Living with fire ants is possible but burdensome and expensive. In parts of Texas, people have changed their way of life to cope with the dangers of Rifa. Shoes are mandatory and Pianta knows of a horse stud operator who has abandoned his business. He cites American invasive species experts’ advice: “Australia doesn’t want a fire ant future.”
What do I do if I see a fire ant?
“I know it’s really difficult but we have to work together, we can’t let these things spread,” Moriarty said of the current biosecurity controls in northern NSW. Report a suspected fire ant nest on the Program website. The NSW DPI is also encouraging the public to report any suspicious sightings online or by calling 1800 680 244.
