Multimillion-dollar effort aims to eradicate menace of fire ant

They are tiny, red and virulent. And, as BILLY ADAMS reports, they are ultimate survivors.

BRISBANE - Just a light poke of the dome-shaped mound of earth sparks a flurry of frenzied activity.

Thousands of tiny insects rush to the surface with a single intention: kill the intruder.

Today that intruder is me, and I'm quick enough in my trusty leather working boots to jump a few steps back.

But I have the upper hand. I knew they were there, was told what to expect and advised to keep out of the way.

For several years the sewage workers at the Carole Park water treatment plant on the outskirts of Brisbane were afforded no such foresight.

Those aggressive ants forced work to be abandoned in areas they had colonised.

The employees all had stories to tell about the painful stings. One worker had an allergic reaction and ended up seriously ill in hospital.

But no one was sure what kind of ant could wreak so much havoc.

Until one day in February last year when authorities made an unthinkable discovery: the red fire ant had found its way on to Australian soil.

The fire ant, a native of South America, is no ordinary small household pest.

They wipe out other insects and small animals, devastate crops and even eat into electrical equipment.

Every year in parts of America, where they have spread out of control, they cause billions of dollars' worth of damage. Their sting is also potentially fatal.

"As a species, they are hugely efficient colonisers and invaders," says Dr Cas Vanderwoude, one of the scientists heading a hastily organised eradication campaign in Australia nicknamed "The Big Nuke".

"If you wanted to build something that was the ultimate survivor, you would make it a fire ant."

It's not hard to imagine the reaction of officials in New Zealand when a fire ant nest was found at Auckland Airport just a few days later.

Especially when they discovered it was probably two years old and inhabited by ants able to fly off and set up new colonies.

The nest, which was in the airport's container storage area, was destroyed and searches of the surrounding site found nothing more.

A mail drop over a 20km area to the south-east of the airport yielded no reports of any suspicious activity.

The experts breathed a sigh of relief. They are now confident any threat has passed.

"We are convinced it did not spread," says Ron Thornton, team leader of the exotic diseases response centre at the Ministry of Agriculture and Fisheries. "We came to realise that this nest was not really thriving and was probably going to die out."

The ants are thought to have arrived in freight. It was the same story in Brisbane, where the first group of ants was found at the city's port.

But the New Zealand experience is minuscule compared to the problem now faced by their Australian counterparts.

The headquarters for the "Big Nuke" is an old school outside Brisbane that was hastily commandeered when the authorities realised what they were up against.

This morning - like every other morning for the last few months - a small army of workers has gathered in what used to be the playground, awaiting instructions for the day's plan of attack.

They are the frontline in the battle against the fire ants, and head out every day to more than 800 sites armed with bait designed to kill off the invaders.

More than A$120 million ($145.5 million) has so far been pledged to the national fire ant eradication campaign, and another A$25 million is being considered.

It is a drop in the ocean compared to estimated losses of almost A$7 billion if the fire ant is able to spread across Australia over the next 30 years.

Keith McCubbin, director of the Queensland Fire Ant Control Centre, says Brisbane has already been the victim of one of the country's worst ecological disasters.

Allowed to spread, major problems like that of the cane toad would seem tiny by comparison.

"I have seen back yards in Brisbane that have a fire ant nest every square metre," he says. "People have not been able to do gardening or mow lawns. You can't let children on to yards without supervision."

The ants endanger traditions like the backyard barbecue. In the United States, some sports fields have become simply unplayable.

"This is something which can only be eradicated through the co-operation of the people out there," adds McCubbin. "There's no way in the world we can go and out find all the ants. But they have to be found or we will have to live with this thing forever."

McCubbin still bears the scar of a bite from a single fire ant which ran up the inside of his trouser leg two months ago.

In a sense, he was lucky. Communicating through pheromones, the ants attack en masse, often leaving victims with hundreds of bites at a time.

"Other types of ant, like the bull ants, deliver far more painful stings," says Cas Vanderwoude, principal scientist at the Control Centre. "But while they attack individually, the fire ants attack in thousands. You are likely to be stung hundreds of times rather than once or twice. They gang up on you. They are very dangerous."

Eighty-four people have died from bites since they were first discovered in America in the 1930s.

It's difficult to believe these creatures could be responsible for such chaos. They are tiny - just 2mm to 6mm in length - and in Brisbane have been commonly mistaken for a harmless native ant.

Unfortunately, the only way to tell the difference (even experts find it hard under a microscope) is when you are bitten. Ugly pustules form on the skin within hours, resembling a particularly severe bout of teenage acne.

Two people are known to have suffered allergic reactions requiring hospital treatment. Because few people knew anything about the ants until a year ago, it is impossible to know if they have been responsible for the deaths of any Australians.

Their threat to the general environment and economy is staggering. Last year the State of Texas, where it is accepted they will never be eradicated, spent US$580 million on the problem.

Although the ants are vigorous defenders of their territory, they also spread rapidly and colonise areas, wiping out other wildlife and plants.

The young queens and fertile males - both winged - emerge in the spring and mate in the air before the fertilised queen lands and sets up a new colony, which is soon inhabited by thousands of worker ants.

When Ron Thornton visited Brisbane last month he was impressed by the scale of the eradication campaign, and the speed with which it was mounted.

The Queensland authorities had no choice. Had the ants been discovered even six months later, Cas Vanderwoude believes it would have been too late to stop their spread.

More than 500 employees have been recruited to the eradication campaign and local businesses have embraced a quality assurance scheme designed to stop the ants spreading through soil, sand and gravel in products like pot plants.

Queenslanders have also been blitzed by a publicity campaign. Today, no one is unaware of the threat.

Results so far are encouraging.

The chemicals - spread over the affected 42,000 hectares manually and by helicopter - prevent ant larvae from developing, gradually wiping out colonies.

The bait also kills other wildlife, but conservationists are pragmatic; it's a necessary evil because the fire ants would get them anyway.

At monitoring sites, scientists have noticed an 80 per cent reduction in the number of worker ants, which normally live for a few months. A similar proportion of Queens - which can survive up to seven years - are said to be infertile.

No infestations have been found outside the two affected areas, to the north-east and southwest of the city centre.

It is accepted that wiping out most of the ants is the easy bit. The final few per cent will prove most difficult. If that's not successful, the ants will soon return with a vengeance.

Thornton is optimistic his Australian counterparts can become the first in the world to disprove the fire ant's Latin name - solenopsis invicta. Invicta means "not having been overcome".

"The sheer scale of the operation over there is quite mind-blowing," he says.

"At first sight, treating a whole bush area and destroying every nest seems very difficult, if not impossible.

"But I think they are being realistic, especially when the bait is proving effective and is being spread in places by helicopter."

But Thornton is confident New Zealanders have nothing to worry about.

Surveillance continues to be carried out at Auckland Airport, and other ports around the country are also being checked.

Apart from the more balmy north of the country, he believes the climate is not suitable for colonies to thrive.

"New Zealand is definitely not a place the fire ant would like to live," he says. "A lot of the country is just too cold to be of great concern."

Keith McCubbin has more faith in the ants' ability to survive more extreme climates, pointing to the example of a cooler part of Argentina where the fire ant thrived.

"Wherever there is a port, there is a danger," he warns.