Dancing Language Of Honey Bees
By Dr. Sandip Pal (Assistant Professor, Department of Zoology, Barrackpore Rastraguru Surendranath College)
Honey bee dancing, perhaps the most fascinating aspect of their biology. Dance is performed by a worker bee that has returned to the honey comb with pollen or nectar. The dances constitute a language that “tells” other workers where the food is located. By signaling both distance and direction with particular movements, the worker bee uses the dance language to recruit and direct other workers in gathering pollen and nectar. Karl von Frisch, a professor of Zoology at the University of Munich in Germany, is credited with interpreting the meaning of honey bee dance movements. Von Frisch’s work eventually earned him the Nobel Prize for Medicine in 1973. Dancing language of honey bee can be of three types viz. round dance, sickle dance and waggle dance.
When a food source is located very close to the hive, generally less than 50 meters, a forager performs a round dance (Figure 1A). She does so by running around in narrow circles, suddenly reversing direction to her original course. She may repeat the dance several times at the same location or move to another location on the comb to repeat it. After the round dance has ended, she often distributes food to the nearby bees. A round dance, therefore, communicates distance, but not direction.
Food sources that are at intermediate distances, between 50 and 150 meters from the hive, are described by the sickle dance. This dance is crescent-shaped (Figure 1B) and represents a transitional dance between the round dance and a waggle dance.
Thomas Seeley describes the waggle dance as “a unique form of behavior in which a bee, deep inside her colony’s nest, performs a miniaturized reenactment of her recent recent journey to a patch of flowers. Bees following these dances learn the distance, direction and odors of these flowers and can translate this information into a flight to specified flowers. Thus the waggle dance is a truly symbolic message, one which is separated in space and time from both the actions on which it is based and the behaviors it will guide.”
The waggle dance (Figure 1C), or wag-tail dance, is performed by bees foraging at food sources that are more than 150 meters from the hive. This dance, unlike the round dance, communicates both distance and direction. A bee that performs a waggle dance runs straight ahead for a short distance, returns in a semicircle to the starting point, runs again through the straight course, then makes a semicircle in the opposite direction to complete a full figure ‘8’ circuit. While running the straight-line course of the dance, the bee’s abdomen wags vigorously from side to side. This vibration of the abdomen produces a tail-wagging motion. At the same time, the bee emits a buzzing sound, produced by wing-beats at a low audio frequency of 250 to 300 Hz. As the distance to the food source increases, the duration of the waggling portion of the dance also increases. The relationship is roughly linear (Figure 2).
The method of communicating direction is more complicated. The orientation of the dancing bee during the straight portion of her waggle dance indicates the location of the food source relative to the sun. The angle that the bee adopts, relative to vertical, represents the angle to the flowers relative to the direction of the sun outside the hive. In other words, the dancing bee transforms the solar angle into the gravitational angle. Figure 3 gives three examples: A forager recruiting to a food source in the same direction as the sun will perform a dance with the waggle run portion travelling directly upward on the honey comb. Conversely, if the food source is located directly away from the sun, the straight run will be performed vertically downward. If the food source is 60o to the left of the sun, the waggle run will be 60o to the left of vertical.
Because directional information is given relative to the sun’s position and not to a compass direction, a forager’s dance for a particular resource will change during a day. This is because the sun’s position moves during the day. For example, a food source located due east will cause foragers to dance approximately straight up in the morning (because the sun rises in the east), but in the late afternoon, the foragers will dance approximately straight down (because the sun sets in the west). Thus, the location of the sun is a key variable in interpreting the directional information in the dance.
Figure 1: Types of honey bee dances
1. Frisch, Karl von. 1976. Bees: Their Vision, Chemical Senses, and Language. Rev. ed. Ithaca, N.Y.: Cornell University Press.
2. Frisch, Karl von. 1967. The Dance Language and Orientation of Bees. Cambridge, Mass.: The Belknap Press of Harvard University Press.
3. Seeley, Thomas D. 1995. The Wisdom of the Hive: The Social Physiology of Honey Bee Colonies. Cambridge, Mass.: Harvard University Press.