MELISSA BLOCK, host:
This is not your usual April Fool's story because in this case, the fool was an ant - an innocent, unsuspecting little ant who happened to be living at Harvard University in the Biology Department, a very big mistake.
NPR's Robert Krulwich tells the tale.
ROBERT KRULWICH: People don't get this about ants, says ant scholar E.O. Wilson, world famous biologist. When we people communicate with each other, we talk.
(Soundbite of laughing children)
KRULWICH: We talk, and talk, and listen, and look.
Dr. E.O. WILSON (Biology Department, Harvard University): Humans are the most audio-visual creatures on Earth.
KRULWICH: But most animals do not communicate our way, not at all.
Dr. WILSON: We are highly unusual. The vast majority of creatures on Earth communicate the way the ants do, by chemicals, pheromones.
KRULWICH: Look closely and you will find little glands on the surface of an ant.
Dr. WILSON: One hair produces one signal. Another one up here produces another signal. They're loaded with glands that they use to communicate with.
KRULWICH: So, if an ant wants to say something to another ant, it chooses a gland to squeeze out a chemical message at a second ant, who then would go?
(Soundbite of sniffing)
Dr. WILSON: I think I smell it, an ant.
(Soundbite of sniffing)
KRULWICH: And that's how they talk. Fifty years ago, Ed Wilson made his reputation figuring out which chemicals produce specific ant messages. For example, he was fascinated by what happens when ants die.
Dr. WILSON: If an ant dies, it just falls over. It may be lying with its feet sticking up.
KRULWICH: And that dead ant will be ignored pretty much by everybody in the colony for about two days, until the corpse is programmed to release a chemical signal, which says I'm dead. At which point, the next ant comes along and immediately grabs the body, carries it off to an ant graveyard. And apparently, every ant knows the I'm dead smell.
Dr. WILSON: So I decided to find out what substances it was smelling.
KRULWICH: Ed told me on stage at the 92nd Street Y in New York City recently that he knew the smell was a very repugnant, stinky odor, a very specific chemical combination.
Dr. WILSON: So, what I did, I got a large array of these substances. I tried?
KRULWICH: The rancid sock smell and poop smell and?
Dr. WILSON: Oh, I - let's see: rotting fish, that's trimethyl amine. I had the essence of feces that's skatole, an indole, and I had all these in pure forms.
KRULWICH: So, his lab was not exactly the favorite spot in the building, but he did have a little ant colony right there in his lab, plus, some plastic ants. And what he'd do is he'd take a few drops of foul smelling chemicals and then apply them?
Dr. WILSON: In very tiny amounts, I was putting them on dummies.
KRULWICH: ?waiting to see what smell would make the ants treat those dummies as corpses.
Dr. WILSON: Until finally, I hit the key substance. And that alone, that does it.
KRULWICH: It was oleic acid.
Dr. WILSON: When they sniff oleic acid, and that's a corpse, so I said, well, if that's the way they do it, will they treat one of their live, healthy nest mates as a corpse?
KRULWICH: So, Ed waited until a little ant just happened along on his tabletop, and he leaned over and he squirted her with the I'm dead signal. And then, the next ant that came along grabbed our ant immediately, says Ed.
Dr. WILSON: Poor thing would be lifted up, kicking, you know, and take it out to the cemetery and dumped.
KRULWICH: And it would pick itself up?
Dr. WILSON: Oh, it would start, yeah, cleaning itself, you know, like a dog trying to get itself cleaned. And then, it would try to re-enter the colony. And if the ant does a good enough job?
KRULWICH: Then the next, the ant would pick it up and slap it back onto a pile of really, truly dead ants, and then it would have to clean itself all over again.
Dr. WILSON: Probably, it would clean out all that oleic acid.
KRULWICH: Then you take, because you started it. Didn't you like to give it a shower or something?
Dr. WILSON: Well, no, I was trying to see if I could create the living dead, you know, a?
(Soundbite of laughter)
KRULWICH: A zombie ant.
Dr. WILSON: You know, an ant that would come back, you know, like this. No, I'm just kidding. I was creating the living dead?
KRULWICH: How long did it take for this very unfortunate, not dead, dead ant to get accepted as alive again?
Dr. WILSON: Well, actually, I'm just, you know, it cleans itself furiously as soon as it's got the stuff on it. It knows it's got a contaminant.
KRULWICH: But after washing and then re-washing, and re-re-washing, Ed thinks?
Dr. WILSON: Roughly an hour or two.
KRULWICH: Science finally had the chemical formula for I'm dead. And the little ant, she resumed her ordinary life presumably unaware of what had just occurred.
Ants, it seems safe to say, have no chemical signals for you wouldn't believe what just happened to me.
Robert Krulwich, NPR News, New York.
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