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What Happens When Leaf-Cutters Can't Cut It?

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What Happens When Leaf-Cutters Can't Cut It?

Research News

What Happens When Leaf-Cutters Can't Cut It?

What Happens When Leaf-Cutters Can't Cut It?

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  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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Leaf-cutter ants rely on their razor-sharp mandibles to snip leaves to pieces. But over time, their mandibles dull. Physicist Robert Schofield of the University of Oregon looked at what happens when the aging ants struggle with their snipping. He found they take on a new job.


I'm Ira Flatow and this is SCIENCE FRIDAY from NPR.

And joining us now is Flora Lichtman with our video pick of the week. Hi, Flora.


FLATOW: We've got some cute critters.


(Soundbite of laughter)

LICHTMAN: Going out with a bang this year. We get up close and personal with leaf-cutter ants.

FLATOW: Leaf-cutter ants.

LICHTMAN: Yeah. I hadn't considered the plight of a leaf cutter until this week. And it's kind of remarkable what they. There are different castes of leaf-cutters, but the foragers - and those are the ones that go out and do the cutting - spend their time going up to leaves and cutting them into tiny pieces. But if you're - it doesn't sound that hard, but if you're an ant...

FLATOW: Right.

LICHTMAN: ...that's like chopping on a tree with your mouth. I mean, you have...

FLATOW: Let me think about that.

(Soundbite of laughter)

FLATOW: And go ahead.

LICHTMAN: Yeah. It seems hard.

FLATOW: Sure, absolutely. Right?

LICHTMAN: So you need some good tools to do it. And Robert Schofield, who's a physicist at the University of Oregon, was interested in leaf-cutter mandibles and how these tools age because you're born and they're really sharp. In fact, he found that they're as sharp as the sharpest razor blade...

FLATOW: No kidding.

LICHTMAN: ...thing you can buy.

FLATOW: The jaws on those leaf-cutter ants?

LICHTMAN: When they're babies.

FLATOW: When they're babies.

LICHTMAN: When they're born. But after all of this leaf cutting, of course, they get a little duller. And so his question was what happened to these ants...


LICHTMAN: ...when, you know, their mandibles dull.

FLATOW: An old age ant. Not good at leaf-cutting anymore.

LICHTMAN: When they can't cut it.

(Soundbite of laughter)

FLATOW: You spend all day on that one.

LICHTMAN: Yeah, I did. And the whole week. It finally came to me this morning.

FLATOW: There you go. So they just throw 'em out like, you know, when you think of our old age homes, someplace?

LICHTMAN: No. This is - it's the feel-good story of today anyway.

FLATOW: The end of the year.

LICHTMAN: The end of the year. The ants that can't cut it anymore take on a new job in the society. They do less cutting and it - and at least in the colony that he looked at, they'd start carrying the leaves so that the ones with the sharper mandibles continue cutting and they don't have to struggle and saw, they can become carriers.

FLATOW: They can schlepp them instead.

LICHTMAN: Oh, yeah. That's great. I don't know if it's better or not. But it did seem, like, you know, here we are on New Year's Eve. If you're feeling outmoded by the Foursquaring, Twittering, Facebooking, you know?

FLATOW: Think about those...

LICHTMAN: Think about the ants. They figured out a new niche for themselves when they can't quite get into the cutting.

FLATOW: And Flora's video pick of the week is up on our website at, up there on the left corner. And you went in and you cut the video together of this great video, of these leaf-cutter ants doing their job.

LICHTMAN: Yeah. You can see them really close doing the cutting. And Schofield says they're really like artisans. It's not just automatons, chopping them into pieces. They have to make decisions about how to use the mandibles to get across the leaf. It's pretty neat footage. Better check it.

FLATOW: And did they have little patterns? Just like the, you know, I was thinking of the old days we used to watch pattern cutters here in New York, you know?

LICHTMAN: He actually called them - he's like, they are little tailors. In fact, they have different, you know, maneuvers for cutting. Sometimes they hold the mandibles and pull them across like you would with a scissors if you were cutting cloth. There are all these different techniques. He thinks maybe that they actually - have figured out techniques to cut down on wear.

FLATOW: And how long do they live, these ants?

LICHTMAN: It sounds like a year for these ants. Although the queen lives much longer, suspiciously to me.

FLATOW: She can pop out a new leaf-cutter whenever she thinks we need some more sharp mandibles.

LICHTMAN: That's right. And, actually, I think, one of the most interesting things I learned this week was that they don't eat the leaves. They actually cut the leaves and then they take them to their nest, they chop them up, and they are, like, these tiny little farmers. They grow fungus on the leaves like...

FLATOW: Mm-hmm.

LICHTMAN: ...cultivate - use them as a substrate for the cultivation.

FLATOW: Mm-hmm. Oh, mushroom.


FLATOW: Mushroom farms. Thank you, Flora.

LICHTMAN: Thanks, Ira.

FLATOW: A happy New Year to you.

LICHTMAN: Happy new year to you.

FLATOW: And Flora's video pick of the week is up there at SCIENCE FRIDAY at And you can see all the other videos. In fact, you can go there and download our podcast. And we have now iPhone and Android podcast if you want to take them along with you.

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