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Argentine Invasion

Monday, July 30, 2012 - 10:00 PM

Drawing of an Argentinte Ant (Adam Cole/WNYC)

From a suburban sidewalk in southern California, Jad and Robert witness the carnage of a gruesome turf war. Though the tiny warriors doing battle clock in at just a fraction of an inch, they have evolved a surprising, successful, and rather unsettling strategy of ironclad loyalty, absolute intolerance, and brutal violence.

David Holway, an ecologist and evolutionary biologist from UC San Diego, takes us to a driveway in Escondido, California where a grisly battle rages. In this quiet suburban spot, two groups of ants are putting on a chilling display of dismemberment and death. According to David, this battle line marks the edge of an enormous super-colony of Argentine ants. Think of that anthill in your backyard, and stretch it out across five continents.

Argentine ants are not good neighbors. When they meet ants from another colony, any other colony, they fight to the death, and tear the other ants to pieces. While other kinds of ants sometimes take slaves or even have sex with ants from different colonies, the Argentine ants don’t fool around. If you’re not part of the colony, you’re dead.

According to evolutionary biologist Neil Tsutsui and ecologist Mark Moffett, the flood plains of northern Argentina offer a clue as to how these ants came to dominate the planet. Because of the frequent flooding, the homeland of Linepithema humile is basically a bootcamp for badass ants. One day, a couple ants from one of these families of Argentine ants made their way onto a boat and landed in New Orleans in the late 1800s. Over the last century, these Argentine ants wreaked havoc across the southern U.S. and a significant chunk of coastal California.

In fact, Melissa Thomas, an Australian entomologist, reveals that these Argentine ants are even more well-heeled than we expected - they've made to every continent except Antarctica. No matter how many thousands of miles separate individual ants, when researchers place two of them together - whether they're plucked from Australia, Japan, Hawaii ... even Easter Island - they recognize each other as belonging to the same super-colony.

But the really mind-blowing thing about these little guys is the surprising success of their us-versus-them death-dealing. Jad and Robert wrestle with what to make of this ant regime, whether it will last, and what, if anything, it might mean for other warlike organisms with global ambitions.

Read more:

Mark Moffett, Adventures among Ants: A Global Safari with a Cast of Trillions


David Holway, Mark Moffett, Melissa Thomas and Neil Tsutsui


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Comments [28]

Jim Okerblom from Escondido, CA.

I live in Escondido, and I know these ants well! I once drank a big swig of 7-Up from my nightstand in the dark, only to discover the carbonation seemed a little more alive than usual. My glass, I quickly learned, was covered with these ants, and soon so were my arms. They actually didn't taste too bad, though. Then there was the time they managed to scare me out of my wits when I was awakened from a sound sleep several times when the smoke detector went off, for no apparent reason, in the middle of the night. Only in the morning did I discover a group of Argentine ants had collected in the detector. They were setting off the alarm periodically when one of them wandered by the sensor. They gather in my 35 fruit trees, mainly oranges, by the tens of thousands, farming aphids in the leaves like they own the place. They are a real scourge! Over the past several years, I have waged an aggressive and determined war against them, and think I finally have the upper hand. It involves an ant bait I make myself out of concentrated sugar water and a few drops of fipronil (which you can buy online as Termidor, a termite treatment). It's the same chemical used in Frontline that I put on my dogs to control fleas. The ants can't detect it, eat the bait with relish, and they all disappear before morning every time -- with luck along with the entire colony. You have to be diligent and keep after them, however. They are a determined foe that I am certain is planning its own strategy for a comeback.

Sep. 15 2017 01:41 AM
Lisalemon from Central Missouri

This is the best RadioLab piece IN THE WHOLE WORLD!!!
Fascinating in every aspect.

Mar. 20 2017 08:52 PM
Mike from Readfield, ME

Hi, Radiolab!

I absolutely love your programming and style. Every broadcast leaves me energized and ready to learn something else new!

Mar. 18 2017 10:38 PM

We stopped by 2211 Eucalyptus in Escondido this weekend and can report that there are no more ant battles in the area. :( If someone has found the new location of the border, please let me know.

Jun. 16 2014 04:41 PM
Tony from Sydney

I remember this advertisement as a boy & me & my mates searching for Argentine ants in the back yard & thinking we will become rich.

Jun. 05 2014 12:34 AM

Thank god these things havent taken over my yard cause i can only imagine what would happen if a mound of these showed up. The family wouldnt like that. But the fact that ants are here from argentina is quite astounding.

Apr. 25 2014 10:30 PM
Andy in Seattle from SEATTLE, OBVIOUSLY

Loved the story, but you forgot that the first rule of fight cup is that you DON'T TALK ABOUT FIGHT CUP!

Jul. 12 2013 09:59 PM
Zoe Cohen

Found an article relevant to this episode. It was a great episode, and even though I listened to it ages ago, I thought about it right away when I saw this!


Mar. 07 2013 09:52 PM
andrew Gladden from england

hey as a brit have these little guys made their way to the falklands yet?? may be we gotta send another task force.....

Jan. 04 2013 04:29 PM
Tiffany Turrill from Berkeley, CA

I appreciate the use of the Aliens score SO much.

Oct. 11 2012 03:07 PM
digital printing perth from chd

I think this is the best way to create new and effective design for your business and T-shirt printing and printing perth

Oct. 05 2012 11:12 PM
Harold Lafrance from USA

Hi there! i have a question about Argentine ants.I want to know why did they come to America?

Oct. 03 2012 03:06 PM
KB Schaller from Florida

What a many-layered lesson society can learn from these creatures; they provide a deeper understanding of the "us" and they "they" mindset. Chilling.

Oct. 01 2012 12:50 PM
chris from GA

i haven't heard the episode yet but i love radio lab. i am a pest control technician, ironically i'm certain i've listened to radiolab while fighting argentine ants before. they are very difficult to remove. i have customers that have a yearly invasions into their yard.

Sep. 26 2012 10:58 PM
Tim Steinert from Kirkland, WA

The only thing I hear on this podcast is the six point two second introduction. It downloads fine (at 45.0 MB & 19:40), but once I play it it magically compresses to 6.2 seconds.

Aug. 28 2012 12:26 AM

An outstanding podcast, it answered many questions that I have about Argentine ants (which are all over my yard, garage, basement, etc. I too would love to see photos or video of the battleground.

A reply to @The Wise Man from New Delhi's question: A few years ago, the San Francisco Chronicle had a piece called "Ants' own chemical may control them." It was about how researchers synthesized chemicals that are similar to those naturally found on Argentine ants, but with a major twist: when an ant sprayed with the chemical reenters the nest, she is vigorously attacked as an invader. The team of researchers is from the University of California at Irvine and includes organic chemist Kevin Shea, evolutionary biologist Neil Tsutsui, and Shea's graduate student, Robert Sulc. The story (found here: ) said that the team and others are working on making the synthetic scent chemical into a pest control tool. I wonder if any progress has been made since the story was printed in 2006?

Given how things move around in California, how long before the Southern colonies set up an empire in Northern California? Or would that not be possible because of the relative size and strength of the current colony?

Finally, what kind of ecological cycling is going on at the battleground? The ants eat nectar and other ant food to make ant bodies, which are then killed in the battle and decompose. What is going on from a nutrient cycling point of view?

Aug. 19 2012 07:44 PM
Maria Lucia Gomez-Greenberg from Tustin CA

Love your show! I am a teacher and will share all this great information with my students and hope we get an entomologist :)

Aug. 18 2012 06:36 PM

Mike... did you get a video? Any pics of the piles of dead ants spilling over the curb?

Wonder what this story is doing to the property value of the house?

Aug. 13 2012 12:39 PM
Mariana Iribarne from Buenos Aires, Argentina

Wow! I am absolutely at awe of this whole episode. I am an argentine and I had absolutely no idea this ants were so famous, so violent, nor that they had conquered the world! Argentines pride ourselves for exporting beef, soccer players and soya beans, but ants! Those were definitely completely out of my radar screen!

Aug. 11 2012 12:30 AM

I love listening to you all while I putter about. Thanks for the great shows but the podcast stops at about 7:20.What gives?

Aug. 08 2012 12:27 AM
Douglas Smith from brooklyn

Mike! yes!

please do. it would be great to see some of the live action from the scene.

Aug. 07 2012 11:09 PM
Mike from escondido, ca

I think I will stop by and try to get some footage. It's right down the street.

Aug. 07 2012 09:55 PM
conta from Slovakia

is there an video of that border where they fight by thousands? Would be interesting to see

Aug. 01 2012 05:17 PM

The first rule of fight cup is: you do not talk about fight cup...

Aug. 01 2012 01:51 PM
Nicholas the Klos from Milton, Wisconsin

While the highly aggressive and exclusive nature may have helped them build an empire, it also may have given them a powerful weakness. A single strain of virus targeting their particular genetic code (which almost doesn't change at all, it sounds) could wipe out the entire planet of this species. Without the ability to adapt, lest they be killed by their brethren, they would not be able to survive such a calamity.

Aug. 01 2012 10:21 AM
The Wise Man from New Delhi

I liked this episode a lot. Is there some pictures anywhere of the border line between the two colonies? Millions of dead ants....
Is there a way to use this massive violence between the two families as a eradication method? The invasive ants seem to be quite a problem on native animals, and perhaps setting them on each other would be a good way to reduce their numbers/influence.

Aug. 01 2012 02:45 AM
bob minder

In the 12th chapter of Walden, "Brute Neighbors," Thoreau devotes three extraordinary paragraphs to ants, particularly to a battle between red and black ants. He notes that his view of the proceedings is far more advantaged than any he'll ever have on human war; and yet he's sure that human soldiers, not even in the Iliad, ever fought so resolutely or with more endurance. After noting how vast the terrain of the war is, he focuses in on a smaller, particular engagement for nearly an hour, offering us descriptions that would send any R-rated-for-violence war film I've ever seen to the cloak room for shame. And he cites the few authors of human history who, at the time, may have spent as much patient time honoring and being honored by such careful attention. The whole thing--and the whole book really--are so extraordinary. Here's one quick passage: "Whether he finally survived that combat, and spent the remainder of his days in some Hotel des Invalides, I do not know; but I thought that his industry would not be worth much thereafter. I never learned which party was victorious, nor the cause of the war; but I felt for the rest of that day as if I had had my feelings excited and harrowed by witnessing the struggle, the ferocity and carnage...."

Jul. 31 2012 08:08 PM

How uncanny! I am currently finishing my Masters degree with an artistic body of work that looks at argentine ants and the way they make trails. I am manipulating their trails with chemical pheromones to make living drawings both in captivity and on the street. Originally from California but relocated to Perth, both of which get mention for the preponderance of argentine ants! I can tell you from having kept them in captivity myself that they are incredible and to be respected. They can escape anything; I've heard scientists describe layers of chemical barriers including motor oil that the ants have been able to penetrate.

It's very telling that they addressed the desire to make metaphors between these ants and humans. On the one hand, we are apt to compare ourselves to them because we recognise so much of ourselves in their sociality, but on the other, they are capable of a level of sacrifice that is horrifying on the human scale. Scientists are right to hesitate to draw comparisons, but it is human nature to be both fascinated and repelled by such familiar/foreign creatures. It seems to me that in these suburban environments we are directly competing for the same resources; they colonise our homes, eat our food, and we spend millions trying to eradicate and control them. Two colonisers from very different evolutionary lineages coming to head! Never before has a radiolab so directly related to my research before.

Jul. 31 2012 07:02 AM

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