The waggle dance of honeybees is a sophisticated communication system, a language that allows a foraging bee to tell others in the hive where to find a good source of food. That explanation for the bees' behavior, proposed by the Austrian zoologist Karl von Frisch in 1923, has been almost universally accepted.
What hasn't been clear, however, is just how effective the waggle dance is.
How well do other bees interpret the movements of their dancing compatriot? Do they usually reach the food source, or do they only get close, relying on odors or other cues to find the exact location?
Thanks to harmonic radar, there are now some answers to those questions. A team of scientists from Germany and Britain used the technology to track bee flights, attaching miniature transponders to bees as they left the hive.
The transponders return radar signals at a harmonic, or multiple of the transmitted frequency, enabling the echoes from the bees to be distinguished from background clutter.
The researchers found that in response to a waggle dance, bees flew straight to the vicinity of a feeder about 200 yards away. But most of the bees then spent several minutes in what the researchers said appeared to be local searching maneuvers, although the feeder was not always located.
At some point, the bees returned directly to the hive. The study was published in Nature.
In a related experiment, after capturing the bees as they left the hive, the researchers transported them far from the feeder. The bees then flew in the same direction as if they had been at the hive, heading toward the feeder.
They never reached the feeder, but many of them engaged in the same local searching behavior at the spot where they expected the feeder to be.
The researchers say their work shows that while the waggle dance is effective, most bees would not reach the food source without using some other cues as well.