Bees Follow Their Leaders
ANDREA SEABROOK, host:
Wait, what's that?
(Soundbite of bees)
SEABROOK: Everybody duck! It's a swarming mass of bees! They're hurtling overhead, going from their old hive to - well, where are they going? And how do they all know which way to go? It's this week's Science Out of the Box.
(Soundbite of music)
SEABROOK: It turns out when a swarm of bees moves to a new home, less than five percent of them actually know where they're going. So why don't the rest get lost? Thomas Seeley is a sociobiologist and bee expert at Cornell University. Professor Seeley, how did they do it?
Dr. THOMAS SEELEY (Department of Neurobiology and Behavior, Cornell University): Well, the short answer is that small minority, that less than five percent that are informed, point the way visually by streaking through the top of the swarm and providing guidance to the rest of them that look up and can see which direction the streakers are moving.
SEABROOK: How did you figure that out?
Dr. SEELEY: Well, I worked with two engineering colleagues, friends of mine at Ohio State, Kevin Schultz and Kevin Passino. And they were really the key people in this, because this question of how a swarm guides itself has been around for centuries. And I was talking with Kevin Passino about it, and he said, well, new digital video technology combined with some new software would enables us to actually track individual bees in this cloud of a swarm of flying bees. The thing is quite large. It's about the size of a school bus.
SEABROOK: It's tens of thousands of bees, right?
Dr. SEELEY: Correct. Typically about between 10 and 20,000 bees.
SEABROOK: So I understand you had to go to an island with no trees with holes in them with them to do this. Tell me why?
Dr. SEELEY: Well, to make this whole set of observations work, a critical thing is you need to have that swarm fly directly over your camera. And normally, you can't control where a swarm of bees goes. The swarm is sitting there. They choose a home site. Normally, it'd be in a forest setting. They'd fly to a hollow tree, and you'd have no idea where they're going. On this island, we could rig it up so that we'd set the swarm up in one place. We put a nest box, their new home, in another, and then we could control the line of flight that they'd move along.
SEABROOK: OK. Let me just make sure I can picture this. The bees start out, and the streaker bees are super fast. They fly up high, and they go in a straight line from the old hive to the new one.
Dr. SEELEY: Right. But they don't keep flying. They'll just shoot or streak through the swarm cloud from the back until they get to the front of the swarm cloud, and then somehow, it looks like they work their way back. We're not sure quite how they do that, whether they fly below the cloud or to the side, and then they'll shoot through again.
SEABROOK: And the other bees watch them and follow them by sight?
Dr. SEELEY: Evidently. It's hard to see how else they would do it other than by sight.
SEABROOK: So this solves a centuries-old mystery, huh?
Dr. SEELEY: Well, it's very strong support for the streaker bee hypothesis.
SEABROOK: And what happens now?
Dr. SEELEY: Well, one of the things we would like to know now is who are these scout bees, these informed bees? We know they're the ones that chose the new home, but what is special about that five percent or so of the bees?
SEABROOK: So how do those scouts, how do that five percent, how did they decide on the new site?
Dr. SEELEY: It's a democracy. Different scouts find different locations, and they basically have a kind of race among themselves over who can convince enough other individuals, first, to get to one of these sites. And the best site wins because the bees are very honest. If a scout finds an excellent site, she will produce very long dances advertising her site. If she finds a poor site, she'll perform weak dances advertising her site. So the buildup occurs most strongly at the best site.
SEABROOK: Thomas Seeley is a sociobiologist and bee expert at Cornell University. He's one of the authors of a new study on streaker bees just out in the Journal of Experimental Biology. Thanks so much.
Dr. SEELEY: My pleasure.