An introduced ant has infested Darwin in the Northern Territory, and poses a serious biological threat to World Heritage Kakadu National Park.
CSIRO PhD student Ben Hoffmann says the Big-headed ant (Pheidole megacephala), originally from Africa, is a highly aggressive species capable of forming enormous colonies, containing millions of ants. In infested areas they wipe out many native ants and other small creatures.
Future control of this nasty little ant could cost millions of dollars unless we do something about it now," he says.
Mr Hoffmann says the Big-headed ant has infested a 25 hectare patch of rainforest at Howard Springs Nature Reserve, just south of Darwin. The ant was accidentally introduced, possibly in imported goods. In heavily-affected areas it has exterminated virtually all native ants. It has also had a serious impact on other native insects, spiders and other invertebrates, reducing their populations by between 40 and 85 per cent.
The ecological balance at Howard Springs is certainly under threat", he says.
Many rainforest patches similar to the one at Howard Springs occur throughout Kakadu National Park, only 150 kms away. They harbour many plants and animals that do not occur in other habitats in the region. Mr Hoffmann said if the Big-headed ant reached these rainforest patches they could have a severe impact on the biological diversity of Kakadu.
The Big-headed ant is rapidly spreading through Darwin suburbs and Mr Hoffmann is now working on its control, with support from the Northern Territory University and the Parks and Wildlife Commission of the Northern Territory.
"Where we have used the chemical hydramethalnon, the Big-headed ant population has been reduced, and native ant populations have been returning", he says. If the ant were successfully eradicated from Howard Springs, it would be a world-first.
If we can spend a few thousand dollars on nipping the problem in the bud now, it might save millions of dollars on future control programmes."
More information:
Ben Hoffmann, CSIRO ph. 08 8944 8424, mobile 015 187 644
Barbie McKaige, CSIRO ph. 08 8944 8411