The waggle dance is a form of communication that honey bees use to recruit nest mates to fly to various locations in their environment where there are good nectar sources. When a worker bee returns to the hive from a successful foraging trip, she can direct her sisters to the place where she found the food using the dance, which encodes information about its direction and its distance.
Many naturalists had observed bees waggling in their hives after foraging, but it wasn't until the research of Karl von Frisch that the meaning of the dance was decoded. He deciphered the recruiting function of the dance and experimentally determined how the bees translate their flight through the landscape into a flight plan for the bees in the hive. After years of research, we now know how the dance is organized. The bees enter the hive and find their way to the brood areas of the comb, where they begin their dance. Recall that in European honey bees, the beeswax combs hang down in vertical sheets inside the colony. The brood area serves as the dance platform, and many unemployed forager bees wait in that area for flight instructions.
Two environmental cues, the position of the sun's azimuth (the angle of the sun against the horizon) and the force of gravity, are the bases for the information communicated in the dance. First, the bees note the direction of the sun's azimuth in relation to North, being the 0 degree position. Based on this system, the sun rises in the East at approximately 90 degrees and sets in the West at about 270 degrees.
If you point toward the sun and then draw an imaginary line from the sun to the horizon, you can measure the direction of that point with a compass. The position of the sun's azimuth varies depending on the time of day, and the bees must somehow learn the rate at which the azimuth moves across the horizon. They take into account the season and latitude, both factors that influence the rate of change of the sun's position.
Inside the darkness of the hive, the bees use their memory of the sun's location and their sense of time to predict the real position of the azimuth. The bees appear to walk in circles as they dance, and they use the dance to point to their flight direction. The azimuth is represented by the direction "up" on the comb, and because the bees in flight measure the direction of their flight relative to the azimuth, they translate that direction on the comb. If they are foraging on flowers located in the same direction as the azimuth, they waggle in a line straight up. If they fly 45 degrees from the azimuth, then they produce their waggle on the comb in a similar angle. The waggle dance, then, is a systematic way for the bees to encode their three-dimensional flight through the environment into a tidy, two-dimensional pattern on the comb.
The distance signal is encoded by the frequency of body vibration, or waggle. If the foraging site is located close to the hive, the waggle is brief; but if it is distant, the waggle is longer. The rate of the waggles is also affected by the quality of the food that the forager collected, so that if the sugar concentration is high, the dance is more vigorous and is repeated frequently; if the sugar content is low, the dance is not repeated. After a waggling run, the bees reset their signal by walking to the right, waggling again, and then walking to the left.
Dancing bees attract the attention of unemployed bees in the brood area, and these bees follow the waggle dances and make contact with the dancer's antennae as they move on the comb. The antennal contact allows the followers to detect the vibrational signals that come from the waggle. In addition, the dancer will stop between waggle runs and will feed small bits of nectar to her followers, which can then pick up floral odors from the dancer that serve as an additional recruitment signal.
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Note: This article was sent to us by: Albert R. Nichels at 08152010
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