Nature's Secret: Why Honey Bees Are Better Politicians Than Humans
Originally published on Tue October 23, 2012 4:49 pm
In the spring, bee hives get so rich with honey, so crowded with baby bees, they often burst in two. Some bees stay in the original nest with a new queen, but a second group, led by the old queen, heads off to establish a new home. If there's a cloud of bees hanging by a tree branch in your back yard, that's them — the house hunters.
How do they choose a new home?
Ah, says Cornell professor Thomas Seeley, this is the beautiful part: The queen doesn't say, "Here's where we're going!" She's not in charge. The decision is made collectively, bottom-up, and it's done by "voting."
Bees are natural democrats. They've been shaped that way by evolution, plus they've got this spectacular, secret extra ingredient (which I'll describe in a minute). But first, here's the routine:
Ten thousand animals need a place to go. Three hundred of them form a kind of house-hunting "Senate." They're the older, more experienced bees. They fly off looking for options: How about that nice hole on the elm tree? Or how about this even nicer hole in the beech tree?
These scout bees announce their "finds" by dancing. (On our radio broadcast, these bees are played by improvisational jazz violinist Mazz Swift-Camlet, so if you want to dance with them, hit the "listen button.")
Each scout's dance tells the other bees how to fly to the site — this is done by "waggle dancing," a figure dance that gives bees directions. And if a bee really likes the site, she will dance her directions over and over and over, literally hundreds of times. That way, more and more of her sister scouts see the dance, know where to go, and can fly off and check for themselves.
If the site is ho-hum, the second wave of bees will do a ho-hum, say, 10-repetition dance. But if the site is spectacular — high off the ground, narrow opening, facing the right direction, lots of honey storage space inside — then they will give it a spectacular, say, 300-round dance, so more scouts will know where to go. If they like the site, pretty soon everybody is doing the same dance: Let's call it "The Elm Tree" dance.
This is how bees "vote;" they dance themselves into a consensus.
In my Morning Edition conversation with Professor Seeley, I asked him what happens if one of the bees is just so convinced that her choice is the right one, that she just keeps dancing and dancing, stubbornly advertising the Beech Tree — not the elm tree. How does the hive handle a stubborn bee?
Seeley says, "We haven't seen any bees like that."
Nope, he says. "In the world of scout bees, you don't have die-hard bees that just dance and dance and dance forever."
Seeley thinks he's got an answer, and it's so strange: After careful observation and testing, he believes that once a scout bee has finished her dance — no matter how strongly she feels about her site — she stops caring.
He thinks there may be "an internal, neurophysiological process that causes every scout to gradually and automatically lose her motivation to dance for a site, even one that is high in quality."
So she's just finished dancing her heart out, telling the hive three times that this beech tree is absolutely, definitely, beyond question the place we need to go, and as soon as she steps back into the crowd, she loses her passion? It just ... dribbles away? And this is genetic? It's built in?
"[It's] built in," says Seeley. He calls this his Retire and Rest hypothesis. "And when you think about it," he says, "that works really well."
Well, It certainly helps things along if there are no fanatic bees, or insistent bees, or principled bees, gumming up the march to consensus. "Those fanatics," Seeley points out, "they're kind of gumming up the works."
True, true. I suppose our House of Representatives would find it a whole lot easier to reach consensus if everybody in the room was automatically drained of passion — and conviction. I'm not sure that's the best way to go about democracy, but it is the bee way.
Tom Seeley, in his book Honeybee Democracy, doesn't exactly admire this genetic "forgetting" in bees, but he does mention its obvious advantages. In science, for instance, eminent scientists often cling to bad ideas until they die.
One difference between aged scientists and aged [bee] scouts, though, is that the people tend to drop out of the debate reluctantly, sometimes not until death, whereas the bees do so automatically. I cannot help but wonder whether science would progress more rapidly if, in this regard, people behaved a bit more like bees.
Maybe "a bit more." But speaking not as a bee, but as me, I'm glad we have our Gandhis, our Lincolns, our Cézannes. Stubborn people with original ideas are what we've got that the bees don't.
MARY LOUISE KELLY, host:
This is the moving season. Kids are leaving college. Families are taking vacations. And if you look in your backyard, you may see some bees hunting for real estate.
Here's NPR's science correspondent Robert Krulwich.
ROBERT KRULWICH: It starts with a hum. You might hear it in the woods, maybe in your backyard.
(Soundbite of bees)
KRULWICH: In springtime, says Cornell Professor Tom Seeley, a beehive gets very crowded. So, often, a bunch of bees will split off, led by the queen, and the first thing they're going to need is a new home. So they've got to choose one. But how they choose, that's the big surprise. It turns out that bees vote. And Tom Seeley has figured out how they do it.
Professor THOMAS SEELEY (Cornell University): They fly out of the parental hive, and it's a mass exodus. And then they reassemble. Once they're outside, they assemble themselves into a beard-like cluster. It's about the size of a soccer ball.
KRULWICH: A beard-like cluster? So that means that they look like a beard?
PROF. SEELEY: Yeah. If Santa Claus had a dark brown beard, that's what it would look like.
(Soundbite of laughter)
PROF. SEELEY: It hangs from a tree branch, and it kind of sways around a little bit like a beard would blow around.
KRULWICH: And when they're swarming, at this point, they're gentle, right? They don't sting you if you were to try to touch them.
PROF. SEELEY: Yes. You can put you - you can go up to them. You can put your finger in the cluster and feel how warm it is inside. You do all sorts of stuff, like you can even do scientific investigations of them.
KRULWICH: Okay. So let us ask: What are the bees now looking for? Well, Tom says, they need a hole in a tree high off the ground, lots of space inside, narrow opening, facing in the right direction.
PROF. SEELEY: So they've got a real problem. Finding first-rate living quarters is not easy for honey bees.
KRULWICH: And it turns out, they don't have any, you know, bee instinct that says: Here's the place. The queen is not involved at all. Instead...
PROF. SEELEY: The bees that go looking - and we call these Nest Sites Scouts. They are among the oldest and probably the most-experienced bees in the swarm.
KRULWICH: And they're a small group, you say, about 5 percent of the hive. So how many bees is that, 5 percent?
PROF. SEELEY: So that would be about three to 500.
PROF. SEELEY: So that's a sizeable search committee.
KRULWICH: Yes. So imagine you're a scout. You're all females. So off you go, wandering the forest. You pass an elm tree, then a beech tree, then an oak tree. Then on the oak tree, you see a nice-looking hole. So you enter. You look around. And then after your inspection...
PROF. SEELEY: What you will do at that point, is you will come back to the swarm cluster, and there you will perform a waggle dance.
KRULWICH: That's a classic dance in the style of a figure eight done by honey bees. And what the waggle dance says is...
(Soundbite of music)
KRULWICH: (Singing) It's here. It's here. To find it, you've got to go here. It's here. It's here. To find it you got to go north by northwest, 120 degrees, by the dandelions and the rhododendrons.
PROF. SEELEY: That's it. Yup.
(Soundbite of laughter)
PROF. SEELEY: Then she runs right around again, back to the starting point and does another one, over and over again. And she's indicating the direction and distance to the site that she discovered. I should mention, she's spent about 30 minutes checking out that site. She's measured all the relevant properties of the site. It's as if she ranks it on a scale of one to 10, 10 being tops.
When she gets back to the swarm, if it's a 10, she might do 300 of these dance circuits, which might take 10 minutes. But if it's only mediocre - let's say it's a three - she might only do 30 of the dance circuits, which could only take a minute or two. And so the better she thinks her site is, the longer, the more persistently she will dance to advertise that site.
KRULWICH: And the more she dances, the more the other scout bees back at the swarm, they get to see the dance. So now they have directions, and they can also visit the same site.
PROF. SEELEY: Exactly. If you're only dancing one minute, it might only be maybe five or six bees that can get the message. If you're dancing 10 minutes, it might be 50 or 60 bees that can get your message.
KRULWICH: So if they like the site, then they come back and they dance the same dance, and dancers beget more dancers and more dancers. And that's how they vote. Eventually, one dance wins.
PROF. SEELEY: This process tends to snowball.
KRULWICH: Now, here's a question: Do they end up making the right choice? I mean, do you know?
PROF. SEELEY: Yes. We know that they do choose well. That was an important question to address.
KRULWICH: He knows because he ran an experiment. He built five, nest-like boxes and placed them near a beehive in Maine.
PROF. SEELEY: And of those five, one of them will be an excellent home site. It'll be a box with 40 liters of space.
KRULWICH: And that's just perfect size. So over and over, and year after year, he let the bees choose a box, which they did.
PROF. SEELEY: And overall, it's probably 90 to 95 percent of the time they choose the best box.
KRULWICH: That surprises me, you know, because I would think if you got a very persuasive, but misguided - you know, an Adolf Hitler Bee...
Unidentified Woman: (German spoken)
KRULWICH: ...but she's like fabulously good at speaking, and she does the best wiggle dances, and everybody follows her to hell. So they all go to the worst possible site.
(Soundbite of laughter)
KRULWICH: Why doesn't that happen?
PROF. SEELEY: The reason that doesn't happen, Robert, is that scout bees do not blindly follow one very enthusiastic dancer.
KRULWICH: In fact, these bees, they don't follow anybody, he says.
PROF. SEELEY: Each of those bees makes her own independent evaluation of that site. And only if the bee judges that that site really is good, will she herself then come back to the swarm and advertise it.
KRULWICH: Ah. So there are checks and balances, here.
PROF. SEELEY: That's right. That's a key part of this whole process.
KRULWICH: So no Hitlers. No bullies. No queen telling you how to vote. The scouts just dance themselves into a kind of voting consensus.
PROF. SEELEY: And that's certainly how it works, here. This demonstrates that democracy really does work.
KRULWICH: Wow. There's one little sneaky thing that nature gave these bees that you just haven't mentioned.
PROF. SEELEY: That's right.
KRULWICH: What about a bee who's absolutely convinced that she's got the best site, and the majority wants an oak tree, she wants an elm tree? And she's thinking no, no, no, no, no, no, no. I will never ever, ever give up.
PROF. SEELEY: We haven't seen any bees like that.
PROF. SEELEY: That's correct. In the world of scout bees, you don't have die-hard bees that just dance and dance and dance forever.
KRULWICH: So what do they do?
PROF. SEELEY: A bee puts forth her opinion for a while, as expressed in her dance, and then she goes quiet. It's what I call the Retire and Rest.
(Soundbite of music)
KRULWICH: So she'll do 300 dances for her elm tree. And then when she's done, all the passion just kind of disappears, just like water going down a drain?
PROF. SEELEY: Yeah, that's it. Yup. Yeah.
KRULWICH: And this is genetic? It's built in?
PROF. SEELEY: That's built in. And when you think about it, that works really well, because it kind of clears the decks.
KRULWICH: I'll say. So now you don't have fanatics.
PROF. SEELEY: Because those fanatics, they're kind of gumming up the works. They're keeping an idea going beyond the point at which it's actually useful.
KRULWICH: On the other hand, you can't get a principled bee. What you get, actually, is animals, who, deep in their DNA, have a nature that favors consensus.
PROF. SEELEY: Yes. Each bee's behavior is tuned, is designed, has been shaped by natural selection to make the swarm a good, decision-making body.
KRULWICH: And do you find yourself admiring these bees?
PROF. SEELEY: Oh, tremendously. In fact, I admire them so much, I've used some of the things that I've learned to organize committee meetings.
KRULWICH: Like what kind of things?
PROF. SEELEY: We had a - recently, a very big debate. Didn't come to a conclusion, and the chairman turned to me and said: Well, Tom, what would the bees do? And I'd have to say, well, Greg...
KRULWICH: Greg, bees aren't ever-fanatics, like some professors we know.
(Soundbite of laughter)
PROF. SEELEY: Yeah, that's right. I prefer to say they're not stubborn.
KRULWICH: Well, that's a much better way to say it.
Tom Seeley's bee studies appear in his book, "Honeybee Democracy."
Robert Krulwich, NPR News.
(Soundbite of music)
KELLY: It's MORNING EDITION, from NPR News. I'm Mary Louise Kelly.
RENEE MONTAGNE, host:
And I'm Renee Montagne. Transcript provided by NPR, Copyright National Public Radio.