AUSTRALIA is on the brink of becoming the latest hunting ground for the red
fire ant as the authorities desperately try to stop it establishing itself
there.
Solenopsis invicta gained a foothold in the country earlier this
year and has already conquered 40,000 hectares around Brisbane. If eradication
plans fail, red fire ants could spread across the country in 30 years.
The consequences are likely to be disastrous in financial and personal terms.
Fire ants can be killers. In the US, where the ants have already spread rapidly
from their home in South America, millions of people are stung each year. In
1984 alone, over a hundred died. The insects also strip sugar and nut
plantations for food, and can drive out native animals. Ants, skink lizards and
other invertebrates are already disappearing around Brisbane.
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Cas Vanderwoude, lead scientist with the Fire Ant Control Centre in
Queensland, estimates repair of chewed electrical wiring, treating stings and
purchasing baits will cost Australian households about A$2 per day.
The federal government and state government of Queensland have started a
five-year eradication programme in Brisbane, using corn and soybean as bait to
attract the ants to pesticides that mimic hormones. These prevent the larvae
developing into adults. More than A$100 million has been assigned to
stamping out the pests, making it the costliest eradication programme yet.
Vanderwoude is confident Australia can do it. 鈥淲e鈥檙e very good at eradicating
[introduced species],鈥� he says. They will be attacking a relatively small area,
and will be guided by the successes and failures of the American eradication
programme.
But Bert Candusio, curator of the Insectarium of Victoria near Melbourne,
says that trying to stop the red fire ants is 鈥渁 lost cause鈥�. 鈥淕oing on past
experiences, fire ants will not be eradicated from Australia,鈥� he says.
Australia鈥檚 climate suits the ant. And in the 1940s the country failed to
eradicate the Argentine ant (Linepithema humile), which behaves and
reproduces in a similar way to the red fire ant.
Fire ants are now the deadliest invasive insect in the US. Having first
arrived in Alabama in the 1940s, they have spread from Texas to Florida, and
most recently to southern California. The ant may eventually cover about half
the US and much of Mexico.
Even if eradication in Brisbane works, the fire ants could already have set
up new colonies in Australia. Ross Crozier, an evolutionary geneticist from
James Cook University in Townsville, Queensland, says people are unwittingly the
most important means of spreading the pests. In March this year, fire ants were
found in Dandenong, Victoria, in 60 pot plants from Brisbane. In October, the
ants appeared again in Victoria, this time in soil in a 12-metre container from
Houston, Texas鈥攖he heart of fire-ant country.