Killer Ants Threaten Australia
Posted: Fri Aug 13, 2004 10:19 pm
BBC News
8-13-4
A giant colony of ants stretching 100km (62 miles) has been discovered in the Australian city of Melbourne, threatening local insect species.
The ants, which were imported from Argentina, are ranked among the world's 100 worst animal invaders.
Although they exist in their usual smaller group size in their homeland, the colonies have merged in Australia to create one massive super colony.
Experts fear that the invasion poses a threat to biodiversity in the area.
Introduced pest
Elissa Suhr, from Monash University, Melbourne, said the introduced pest's natural aggression kept numbers under control in its native country.
But the lack of genetic diversity in the ants found in Australia has allowed them to build a super colony.
"In Argentina, their native homeland, ant colonies span tens of metres, are genetically diverse and highly aggressive towards one another," Dr Suhr said.
"So population numbers never explode and they are no threat to other plants and animals.
"When they arrived in Australia, in 1939, a change in their structure occurred, changing their behaviour so that they are not aggressive towards one another. This has resulted in the colonies becoming one super colony."
Dr Suhr said the Argentine ants have killed native ants, and consumed many other insects, posing a major threat to biodiversity.
Taking over
She said Argentine ants could even displace native species by taking over local habitats and preying on insects commonly eaten by Australian ants.
Australia is not the only country to be invaded by Argentine ants, according to Dr Suhr.
"In California, they have displaced native ants, decreased the diversity of other native insects, affected the dispersal of seeds and even decreased lizard numbers," she said.
Australian scientists are studying colonies in Perth and Adelaide to see if they share the same genetic structure and behaviour as the Melbourne ants.
If they do, a super colony several thousand miles wide could spread across southern Australia.
© BBC MMIV
http://news.bbc.co.uk/2/hi/science/nature/3561352.stm
8-13-4
A giant colony of ants stretching 100km (62 miles) has been discovered in the Australian city of Melbourne, threatening local insect species.
The ants, which were imported from Argentina, are ranked among the world's 100 worst animal invaders.
Although they exist in their usual smaller group size in their homeland, the colonies have merged in Australia to create one massive super colony.
Experts fear that the invasion poses a threat to biodiversity in the area.
Introduced pest
Elissa Suhr, from Monash University, Melbourne, said the introduced pest's natural aggression kept numbers under control in its native country.
But the lack of genetic diversity in the ants found in Australia has allowed them to build a super colony.
"In Argentina, their native homeland, ant colonies span tens of metres, are genetically diverse and highly aggressive towards one another," Dr Suhr said.
"So population numbers never explode and they are no threat to other plants and animals.
"When they arrived in Australia, in 1939, a change in their structure occurred, changing their behaviour so that they are not aggressive towards one another. This has resulted in the colonies becoming one super colony."
Dr Suhr said the Argentine ants have killed native ants, and consumed many other insects, posing a major threat to biodiversity.
Taking over
She said Argentine ants could even displace native species by taking over local habitats and preying on insects commonly eaten by Australian ants.
Australia is not the only country to be invaded by Argentine ants, according to Dr Suhr.
"In California, they have displaced native ants, decreased the diversity of other native insects, affected the dispersal of seeds and even decreased lizard numbers," she said.
Australian scientists are studying colonies in Perth and Adelaide to see if they share the same genetic structure and behaviour as the Melbourne ants.
If they do, a super colony several thousand miles wide could spread across southern Australia.
© BBC MMIV
http://news.bbc.co.uk/2/hi/science/nature/3561352.stm
