The Ant Wars
We are bombarded with so much news these days that many Sydney residents would have missed the reports last November about fierce fire ants on the city’s doorstep that threatened to ruin the Australian way of life and ‘cost the economy billions’.
Those who noticed could take heart from the NSW government’s robust response. The single nest found at a Port Botany freight terminal drew a swarm of emergency response experts, aided by three ‘elite’ odour detection dogs with enough snout-power to zero in on a single ant. Poisons were laid and hundreds of home gardens searched up to two kilometres away in an operation leaving little to chance.
The dogs were on loan from Queensland, where, since 2001, close to $300 million has been spent trying to oust red imported fire ants (to give them their full name) from around Brisbane, so far without success. Funding decisions to be made soon could decide whether Australia ends up like the southern US, where, to quote Texan professor of entomology Bradleigh Vinson, people in infested areas “do not have picnics on the lawn, go barefoot, sit or lay on the ground, or stand in one place without constantly looking at the ground near their feet to be sure the ants are not swarming up their legs.”
Australia abounds in assertive insects but none of them operates like these ants. In the US they cause such unlikely problems as fires, potholes, computer failures, crop losses and blindings of farm animals. More than 80 people have died from the stings, mainly from anaphylactic shock. A growing problem in nursing homes is elderly patients killed by ants in their beds. One woman died in a house fire after fire ants caused a short circuit. When one ant is electrocuted the pheromones it releases attract its comrades, until the masses of dead bodies trigger failures of light switches, air conditioners, traffic control lights, pumps, meters, even car electrical systems. North Americans spend more than $6 billion each year dealing with the problems.
Australia in recent years has gained other nasty ants, including one that attacks people in their swimming pools. So tiny are electric ants – 1-1.5 mm long – that when they fall from trees they float on water in substantial numbers. One home-owner felled the trees beside his pool to stop the stings. Gary Morton, who runs the Queensland Government’s electric ant eradication program, initiated after the ants were found at Cairns in 2006, told me they deliver “instantaneous pain then throbbing that lasts for a few hours.”
Like fire ants, electric ants conduct themselves without regard for the sanctity of the home. Morton mentioned one person stung in the bath, another on the toilet. “We found foraging lines going up the bowl.” In the Solomon Islands, where these ants are entrenched, some residents keep their bed legs in cans of water to thwart nocturnal stings. In New Caledonia scores of dogs and cats are blinded after ants commandeer their food bowls.
The federal government has provided two million dollars to rid the Wet Tropics of another little disaster, the yellow crazy ant, lest north Queensland end up like Christmas Island, where more than 10 million red land crabs have been killed, and a bat and lizard recently went extinct (although they had more going wrong for them than ants). Executive director of the Wet Tropics Management Authority Andrew Maclean told me that if they prevail we can expect to have crazy ants spraying acid into the eyes of endangered cassowary chicks. When ant expert Lori Lach put hundreds of butterfly caterpillars into a crazy ant site most were carried off inside three hours. One crazy ant colony on a Kuranda creek bank is posing a conundrum because insecticides can’t be applied at the water’s edge, and this site happens to be one of only ten to host the endangered Kuranda tree frog. Conrad Hoskin, the biologist who discovered and named this species, said he would rather see a whole frog population poisoned than have the ants spread.
In 2006, the federal government published a Threat Abatement Plan in an effort to reduce the impact of tramp ants on biodiversity. Of greatest concern are the fire ants found around Brisbane, the electric ants in the Cairns area and the yellow crazy ants spreading at several sites in Queensland and the Northern Territory. The first two could possibly thrive as far south as Melbourne; their footholds have more to do with their initial points of entry into the country than with their ideal climate range.
No one should suppose that modern technology has put us beyond the reach of harmful nature: in recent decades, horrific diseases have jumped from animals to humans – ebola virus, SARS, Hendra virus, bat lyssavirus. Tramp ants are a parallel threat.