- 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.
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- Experts fear that the invasion poses a threat to biodiversity
in the area.
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- Introduced pest
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- 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.
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- Taking over
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- She said Argentine ants could even displace native species
by taking over local habitats and preying on insects commonly eaten by
Australian ants.
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- 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.
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- Australian scientists are studying colonies in Perth
and Adelaide to see if they share the same genetic structure and behaviour
as the Melbourne ants.
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- If they do, a super colony several thousand miles wide
could spread across southern Australia.
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- © BBC MMIV
- http://news.bbc.co.uk/2/hi/science/nature/3561352.stm
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