Battle of the crazy ants

An Arnhem Land project involving the local Indigenous population, big business and scientists is working to contain these introduced pests.

Story By Ken Eastwood

With keen eyes and a whole lot of patience, an Arnhem Land community has been faithfully tracking down and removing invasive yellow crazy ants, preventing their disastrous spread across the Top End.

A combined project of the Dhimurru Aboriginal Corporation, Rio Tinto Alcan Gove and the CSIRO, the yellow crazy-ant management program won the biodiversity category of the United Nations Association of Australia World Environment Day Awards earlier this year.

“We’ve been running the crazy-ant program for about eight years,” says Dhimurru’s executive officer, Steve Roeger. “Dhimurru’s role was to act on concerns raised initially by the Northern Territory Parks and Wildlife Service.” Steve says locals had noticed the ants arrive some years before, “but it wasn’t something on our radar at all until Parks and Wildlife approached us directly. People we’re talking to today have probably been seeing them most of their lives.”

Although they are probably not as dangerous to humans as the introduced fire ant, crazy ants – so named because they run frenetically when disturbed – are easily transported by humans. They can become very destructive in an environment, eating everything in their path and driving out native species, particularly other invertebrates. On Christmas Island, in the Indian Ocean, they have killed an estimated 20 million red crabs, or 30 percent of the total population.

“We don’t even know where it was native to, because it was so good at spreading around the world,” says CSIRO ecologist Dr Ben Hoffmann, who has been involved in the Arnhem Land project. He says the ant is generally believed to have come from South-East Asia, but some researchers believe their origin is Africa. “Ants are very commonly spread by people because they can hide in every little nook and cranny of things we carry, such as earth-moving equipment. Arnhem Land has a lot of historical mineral exploration and any equipment moving from Asia could have brought this in.”