The Austrian scientist Karl von Frisch observed one day in spring 1919, after marking with a paint stain a forager exploiting a cup of sugar water: "The worker returning to the hive began to dance in a circle, surrounded by 'bees who showed great excitement, which caused them to fly towards the full cup. " His team’s work has unraveled many of the mysteries of dance. They were recognized worldwide and sanctioned with the Nobel Prize in Physiology and Medicine in 1973.
First, the bee, which has found a food source, regurgitates part of its nectar crop. Then it generally goes to a well-defined location in the hive and performs a dance in circles: it rotates one or more times clockwise, then in the opposite direction and so on. It indicates a nearby food source without specifying a direction.
Several workers, first attracted by the smell of nectar, approach, follow the recruiter, and reproduce the latter's dance. Under normal conditions, the dance is performed in the dark of the closed hive. The other bees cannot therefore see the dancer, and if they notice her agitation and follow her closely in all her evolutions, it is exclusively thanks to their tactile and olfactory perceptions. They capture movement by means of their antennas and perceive the scent of food. Then the followers leave the hive.
When the discovery is farther away (>75/100m), the scout who comes to warn her companions performs a more complicated dance, intended to tell them the direction and the distance from the place to be discovered: this is the waggling dance.
On the honeycomb, the bee first makes a short straight path (crossing a maximum of five rows of cells, in the case of long distances), wriggling several times per second; it then describes a semicircle on one side which brings it back to its starting point, repeats the rectilinear path, and describes a new semicircle symmetrical to the first. The scout thus repeats this full course for a few minutes. With each straight line, the dancer starts to waggle the abdomen, that is to say to make it vibrate quickly from left to right while emitting a rhythmic hum. This wriggling indicates the direction of the food in relation to the sun. The alerted bees then begin to follow the dancer and palpate them from their antennae in order to receive various messages.
Bees have a very fine sensitivity towards vibrations of their support. Therefore, when they step on the shelf, they can perceive the sizzling noise of the dancer because the vibrations stimulate tiny receptors hidden at the legs. The wriggling dance, and especially its phase of rectilinear journey with wriggling, is followed by the accompanists with great attention.
The dance is accompanied by a sound emission: the dancer emits short bursts of vibrations with her wing muscles at very low frequencies. Besides, not content to see, the spectator also wants to taste. She makes a short sound, like a complaint, and the dancer then stops to give her some nectar.
Foragers will record the direction, distance, abundance and nature of the source of the loot discovered using their olfactory, tactile and vibrational senses. If the bee is quivering vertically, head up, it means that the food is in the direction of the sun (I).
If the right makes an angle of 80 ° to the left, the foraging field is in a direction located 80 ° to the left of the direction of the sun (II). Turn everything around, the bee wiggles vertically, but upside down: the food is exactly opposite the sun (III).
Von Frisch was able to establish a relationship between the frequency of wriggling, the duration of the complete cycle carried out by the bee and the distance from the source. The farther the source of food, the greater the number of fluttering and rustling of wings. The duration of the course of the straight line during the performance of the wriggling dance by the scout is directly proportional to the duration of the journey it has just completed. The dancer constantly updates the position of the sun. The angle is indicated in relation to the position of the star at the same time and not in relation to that occupied by the sun at the time when the scout made its discovery!
In addition to the indications on the position of food, the recruiter informs her sisters on the nature of her find and its quality, on the one hand using the pollen with which she is covered and the odors which she carries, and d on the other hand, by regurgitating part of the harvested nectar or even by antennal communication. The richness of the booty depends on the amount of nectar that the flowers secrete and its sugar concentration. At the end of the wriggling line segment, the dancer returns to her starting point by describing semicircles alternately to the right then to the left. The faster the return speed, the better the food tasted.
The scout bee indeed brings back from her exploration the specific scent of the flower. The bees to speak to the smell of their companions and attract them to a source of nectar, use their scent organ (Nasanov gland), when flying over the flowers, when a promising harvest makes the collaboration of other auxiliaries desirable. After performing her dance in a circle, the scout first returns to the spotted flowers, brings out her fragrant organ and perfumes the ambient air. It facilitates the discovery of the goal by this call of the perfume. The alerted bees will thus arrive straight to the point.
When a treasure is exhausted, the foragers will return gradually without dancing and the interest will be focused on already known sites or on new discoveries.
It is also important to evoke the concept of negative signal or stop signal, "Do not go there". This signal is addressed directly to the dancer and has the effect of preventing her from recruiting to a particular source of food. The stop signal is issued by a forager who has been attacked by a predator on a flower for which the dancer is dancing. The alarmed forager follows the dancer and, during the return semicircles, she gives him a series of head shots while emitting brief intense buzzes. After a while, the dancer stops. This stop signal will also exist if the alarmed bee had to flee in front of bees from another colony who were fighting for its place.
We have described the dances relating to food, but the bee dances in many other circumstances; more than 1,500 bee dances have just been studied. All these dances make it possible to emit vibration signals which modulate many activities of the hive, also called "modulating communication signals". They largely concern the activities of foraging and swarming, are directed towards workers of all ages and generally cause locomotion and increased activity in the colony.