Electric ants invade northern Australia

By Elliot Brennan 5 May 2011
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The electric ant, which gives a painful bite, has invaded parts of Far North Queensland.

THE ELECTRIC ANT, ONE of the world’s worst alien species, is spreading through parts of northern Queensland, posing problems for local residents, pets and wildlife.

Since being discovered in Smithfield, Far North Queensland in 2006, electric ants – which pack a powerful and painful bite – have spread across about 260ha in and around Cairns. Recently infestations have been discovered at Craiglie, just south of Port Douglas in Queensland.

The ant (Wasmannia auropunctata) is considered one of the worst alien species in the world according to The Global Invasive Species Database. Populations of electric ants, native to South America,  have already infested parts of Africa, North America and several Pacific Islands to detrimental effect.

“Where electric ants are present, they have displaced 95 per cent of native ants”, says Gary Morton, coordinator for the eradication program at Biosecurity Queensland. Without native ants, local plants, crops and trees in the ecosystem may suffer, he says.  

Efforts by Biosecurity Queensland’s National Electric Ant Eradication Program have so far proved no match for the tiny invasive species, though new methods, including using dogs to sniff them out, may yield better results.

“Australia has a dozen or so invasive species of ants. Of the most invasive species in the world, we have them all,” says Dr Alan Andersen, chief research scientist at CSIRO. “The Australian bush has native ants that have kept most invasive ants out of the bush,” Alan says. Electric ants have thus far been restricted to urban areas, he says.  

Electric ants’ painful bite

The tiny, bright orange invasive ants, no more than 1.5mm long, are so called because of their painful sting and destructive appetites. They have a penchant for attacking the cloacae and eyes  of tortoises and domestic pets, often blinding them. The ants’ taste for eggs and hatchlings are believed to be responsible for a decline in reptile populations in New Caledonia and the Galapagos Archipelago.

“Recently a goanna was found blinded by these ants and had to be euthanased,” Gary told Australian Geographic. Electric ants can inflict a painful bite, on par with that of  the red fire ant, and resulting in skin irritations, pimples, rashes and itching for three to four days. Cases of severe allergic reactions to the ant bits have also been reported.

In August last year, authorities were alerted to a colony of electric ants at a playground in the suburbs of Cairns. A doorknock of the area found many children covered with welts and ant bites. Unlike many ant species, electric ants don’t construct nests, but capitalise on shelters in their surroundings. Often colonies are found in garden waste and potted plants, but they’ve also been known to inhabit, wall cavities, bedding and swimming pools, where they have a tendency to ‘jump in’ en masse, forming a raft of bodies on top of the water.

Electric ants’ eradication efforts

The eradication program, managed by Biosecurity Queensland, aims to eliminate the ants from northern Queenslands through surveillance, treatment of infested areas and quarantine measures to control the spread of the introduced species.

The world’s first electric ant odour detection dog has joined the fight to eradicate the exotic ants. Electric ants, like fire ants, emit a pheromone that can be tracked by dogs. The new recruit is assisting in the eradication process by quickly detecting infestation and confirming absence of the ants.

According to an economic impact assessment commissioned by Biosecurity Queensland if electric ants are not eradicated within 30 years it could cost agriculture almost $10 million a year and the local tourism industry $3.9 million a year. Treatment costs could run into the tens of millions of dollars. The fire ant, another invasive ant species that smuggled its way to South East Queensland, has been difficult to eradicate.
To report any suspect ants or unusual bites or stings contact Biosecurity Queensland on 13 25 23.