STUNG: An Asian needle ant attacks a termite.
Image: By Benoit Guenard
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The Argentine ant has spread to every continent except Antarctica, overwhelming native ants with sheer numbers and fierce battle tactics. But they may have met their match in a recent arrival: the Asian needle ant. The cross-species face-off, a surprise to entomologists, could topple ecosystems where the battle lines are drawn.
Invading ants make up just handfuls of the more than 12,400 described ant species in the world, says Jes Søe Pedersen, an associate professor at the Center for Social Evolution at the University of Copenhagen in Denmark. Yet, their impact on ecosystems, human health and the economy far outstrips their Lilliputian size. Red fire ants can endanger the lives of those who unwittingly stumble on a nest. Some invasive species are agricultural pests or “farm” voracious plant-eating aphids to milk them for their sugar-laden excrement.
Invasive ants often kill, eat or outcompete native ant species—the latter of which play key roles in the ecosystems where they make their homes. Many native ants are gardeners—they till the soil and plant seeds. Alien ants that come from a different environment do not pick up the jobs of those they push out.
The invaders can also create an ecosystem meltdown: Yellow crazy ants that invaded Christmas Island aggravated native birds so much that they have changed their eating habits and feast on the island’s famous red crabs. Food competition from the ants, combined with other invasive species such as feral cats and black rats, may have led to the extinction of the Christmas Island pipistrelle bat.
Figuring out an invading species’s impact on an ecosystem is tricky. Researchers rarely observe an invasion in progress. But this time may be different. The opening salvos between the newly recognized invasive Asian needle ant and the more notorious Argentine ant offer just that opportunity, Pedersen says.
Researchers at North Carolina State University in Raleigh unexpectedly stumbled on the unfolding ant war several years ago. Eleanor Spicer Rice, a graduate student studying entomology at the time, was tracking a network of Argentine ant nests in an office park in North Carolina and found a few nests of Asian needle ants. “It is really weird that another ant could be nesting within the Argentine territory,” Spicer Rice says. Argentine ants do not tolerate competition. Typically, they are able to push other ants out of an area by attacking the rivals and dominating food sources. Originally from South America, they form massive interrelated networks of nests called super colonies.
The situation seemed unprecedented. The largest ant colony in the world is an Argentine ant super colony spanning more than 6,000 kilometers in the Mediterranean region. For some reason, across a few square miles of North Carolina the Argentine ants’ world-conquering strategy was not working. The Asian needle ants were, in fact, gaining ground. In March 2009 Spicer Rice and her colleagues found Argentine ants at 90 trees, sharing nine of them with the Asian ants. By June 2011, the Argentine ants had been driven back to 67 trees, were neighbors with the interlopers in 15 and the Asian needle ants had taken over 17 of the sites.
To see if the Asian needle ants were driving the other species away, the researchers selectively poisoned the Asian needle ants in some areas. The Argentine intruders returned, indicating that predators, resource availability or other factors were not behind their initial retreat.
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Add CommentTheir coming!
Reply | Report Abuse | Link to thisMaybe it's because i like the big battle scenes in movies such as federation vs klingon, empire vs rebels, spartans vs everyone else, but i am just wondering if there are any links to an actual argentine vs asian needle ant battle taking place.
Reply | Report Abuse | Link to thisHey! What´s "a handful of the more than 12,4000".
Reply | Report Abuse | Link to thisWah, invasive? RAID kills bugs dead. And so does Tero.
Reply | Report Abuse | Link to thisIncredible!
Reply | Report Abuse | Link to thisBut surely the asian needle ant is not a saviour? Does it have similar impacts as the argentine ant on native species? i.e. can it coexist with native ants but prevent supercolonies of argentine ants forming?
I honestly think the statements about fire ants out competing native ant species is a completely UNproven statement that has been repeated so many times without anyone asking for proof that it has become accepted as true.
Reply | Report Abuse | Link to thisThe reason I say this is I've lived where fire ants have been present for at least 50 years, and while yes they are nasty foul insects that I hate that seem to be everywhere SO TOO DO MANY OTHER TYPES OF ANTS that should not be there if the above statement were even partially true.
Tiny little black ants are everywhere for example.
What more likely has happened is the fire ant has taken over the obvious and visible niches in the environment from the native ants, but has NOT come anywhere near driving them out or exterminating them.
You can find about every type of ant around here that I found as a child with ONE exception and that is the giant Harvester ants.
Their disappearance locally however is NOT due to fire ants as much as it is due to this area getting significantly more rainfall over the last few decades.
Since this was the outer edge of their normal range, such a significant change meant it was no longer a good place to live for them.
Yet people blame the fire ants with no proof whatsoever.
Reply | Report Abuse | Link to thisIn the 20 yrs on my property ants have changed 5 times with tiny black ones I call 70Deg ants as they don't come out until the temp is 70F have ruled the last 7 or so. But for 4 moths or so they just disappear.
Because of this they are unlikely to go much more north.
But they drove the fire ants out and if you don't have food hanging out they don't bother you.
When I was a kid, growing up in rural central Florida, we had no fire ants. My parents would take us for picknicks on the river bank, and we could play and eat without worrying over ants. When I returned after my military time, they were everywhere, and some people were dying from allergic reactions to their bites. I don't know if they completely wiped out any of the other species, but I can think of at least three which I have not seen in forty years. Hopefully they are holding out somewhere and (also hopefully) the fire ants will not follow me to the high NC mountains where I retired.
Reply | Report Abuse | Link to thisJerryd, you can keep the fire ants, palmetto bugs(American roach), love bugs, mosquitoes, alligators, poisonous snakes, sand gnats, no-see-ums, numerous spiders, heat and humidity, etc, etc, ......
The only things I miss are citrus, guavas, mangoes, starfruit, and avocados in my yard.
You know what's the most invasive species in the world? Not ants, but human beings.
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