THOMAS D. SEELEY: One of the things that I find most fascinating is a phenomenon called swarm intelligence, or collective intelligence. This is a process whereby groups of animals organize themselves to make good decisions. And we've long known that groups of animals can work better than individuals in doing such things as capturing prey and defending themselves. It's only relatively recently that we've understood that another advantage that groups have over individuals is in their ability to make decisions.
What I've got here is a swarm of bees. This is a swarm of bees that I've mounted on a board. By putting them on this board, it just spreads them out so that I can watch their behavior more easily.
In nature, they would have clustered on a tree branch. And what they're doing is they're-- they've left their parental hive. The parental colony became very strong. The old queen-- the mother queen-- left with about 2/3 of the workers and forms this assembly, or bivouac, and they do this because when they leave the parental hive, they actually haven't chosen their new home. So they make this temporary stop here, get their bearings, get assembled. Figure out who's going to go in the swarm, who's going to go back to the parental hive.
And from here, the scout bees go out searching for home sites and conduct their search for a new home, which usually takes at least a few hours, and sometimes a few days. This is a group that shows swarm intelligence par excellence because they're a group of bees that are homeless and they have a very important decision to make. They have to decide where their new home is going to be.
And they bring to this task the fact that they've got several-- the swarm as a whole has about 10,000 worker bees and one queen bee in it. Of those 10,000 or so bees, only a few hundred are actually involved in the decision making. But still, when you think about it, that's several hundred bees that can go searching far and wide for potential home sites, which would be cavities in trees. And it's several individuals-- not just one-- that can then debate the possibilities, kick the ideas around, and decide among themselves, through debate, which one is actually the best.
And I think you can see that that's a very powerful way to make a decision. If you've got a group of individuals that are cooperative, willing to work together to find the options, talk about the options, identify the best one, and then agree to go forward with the one that's the best choice. That's what we call swarm intelligence and I like to investigate it with a real swarm-- a swarm of bees.
This bee is indicating the direction to her site by the direction of the waggling. For example, she's-- if you imagine a clock face-- she's orienting-- if she walks forward while waggling, she's orienting, or pointing, at about 5 o'clock. And that means that-- and the reference that she uses to orient to choose that 5 o'clock direction is straight up on the swarm. And that means that a bee that's following her dance knows that when she leaves the swarm to find the sight she's indicating, she should orient at 5 o'clock relative to the sun.
In other words, the bee would leave the swarm, figure out the direction of the sun, and then go off, fly off in a direction that would be 5 o'clock from that direction of the sun. If this site-- for example, if she were pointing her dance straight down at 6 o'clock, that would mean the direction to the site is directly away from the sun. If her dance were-- if she were doing these waggles walking straight up on the swarm, that would mean the site that she's advertising is right in the direction of the sun.
And then, the distance is indicated in the dance by how long each one of these waggle runs lasts. Let's time this-- let's roughly time this one. 1,001, 1,002, 1,003-- a little-- about three seconds. 1,001, 1,002, 1,003, 1,004-- somewhere between three and four seconds. And the conversion is about one second of waggling represents approximately 1,000 meters of distance to the potential home site.
So this home site is between 3,000 and 4,000 meters away. And in miles, that would be between 1.8 and 2.4 miles away. So quite a good distance.
And one of the things I find most remarkable of all about the bees is that the site that she's indicating is a hollow tree-- a tree with a cavity in it. And it might be one tr-- it might be in a forest. So it's one tree in the middle of a woods. And it's at a certain direction from here. It's several miles away.
And these other bees that are following her dance are actually able to take those instructions with sufficient accuracy, sufficient precision, and go out and find the site that she's advertising. Isn't that amazing? I find it so. I don't think I could do that.
I could read her dance. I could measure her angle quite precisely. And I could get the distance information precisely. But could I then use it and find the tree? Only with great difficulty.
One of the features of the decision making by the bees is that they-- the process is built upon disagreement. It starts with-- of these several hundred scout bees, each one will fly out, search around. They will typically, among them, they'll find a dozen or more potential home sites. And those bees that find potential home sites will come back and advertise them with dances. So you can have-- on the swarm, at any one time-- a dozen or more different sites being advertised by the dances.
And so they then have the problem of how to sort it out, how to winnow out all but the best one. And they have a very-- they have a process that's a lot like a political election. You think about it, you've got-- in a human political election, a democratic election-- you've got multiple candidates. You've got supporters for the different candidates. The supporters for the different candidates produce advertisements, try to recruit the uncommitted voters to favor their candidate.
The scout bees do essentially the same sort of thing. You've got bees that are affiliated with different sites. They perform advertisements to draw uncommitted scouts to their site. And one thing that's critical about the way it works in the bees is that their advertisements are all completely honest.
And what I mean by that is that if the site is-- they adjust how long they will dance, whether it's one minute or 10 minutes or 20 minutes. A scout bee will just how long she advertises her site according to the goodness of the site. The better the site, the longer the dance. And what that means is that an excellent site will be advertised more persistently.
The build up of interest in that site will proceed most rapidly. And in the bees' political contest-- they run the contest until one of the sites-- until one of these candidate sites-- reaches-- has gained enough, or a critical level of, interest-- a critical level of visits by scout bees. And once that site has achieved that, the bees visiting that site recognize that oh, yeah, our site has reached the quorum the critical level. Our site has won.
And then they come back and they announce to all of the other bees that the debate is over. They can proceed, now, to implementing their decision. That's how it works with the bees. And except for that last little part at the end, by using a quorum rather than a majority rule, the way they make their decision and deal with disagreement is very much like our own political elections. Isn't that amazing?
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When a honeybee colony becomes overcrowded, a swarm of thousands departs with the old queen to form a new colony.
Cornell professor, biologist and beekeeper Thomas Seeley explains how honeybees use swarm intelligence to make the critical decision of which new nest site to pick.
Seeley's book, "Honeybee Democracy" was published in 2010 by Princeton University Press.