In 1788, Pastor Earnest Spitzner witnessed an amazing fact: When a Carniolan honeybee finds a good supply of pollen, she returns to the hive and there she tells the other bees about it. Spitzner suggested that the bees can communicate with each other by performing a curious circular dance. Both the beautiful observation and the deduction were correct, but Spitzner took it no further. It was left to Karl von Frisch, in our age, to interpret the language of honeybees.
When a honeybee discovers a new source of honey within about ten metres of the hive, she returns to the hive and regurgitates drops of honey which are eagerly drunk by other bees. Then, in order to indicate the source of the drops they have just drunk, she performs an interesting sequence of movements we call the ‘round dance’. She dances round in a circle, first in one direction, then reversing and going round in the opposite direction, again reversing and so on. During the performance, other bees follow her about, holding their antenna against her abdomen. After the dance, she flies back to the food source, normally a particular flower or group of flowers. The other bees who followed the dance do not fly after her but fly out in all directions. However, fairly soon, a great number of them find the new source. They do so because they have smelt the scent of the flowers that clung to the dancer’s body and so to recognize the right kind of flower. Observing this procedure of the bees’ communication with admiration, Frisch reported that the ‘round dance’ tells the other bees to go out and search in the near neighbourhood of the hive; and the scent on the dancer’s body tells them which flowers to look for. In one experiment, bees informed by a dancer at once found the right flowers in a section of Munich Botanical Gardens where 700 different plant species were blooming.
But honeybees search for food at a greater distance than 10 metres. They have been observed to fly more than 13 km in search of honey. Remembering the average that a honeybee is only about 13 mm long, that 13 km for a bee is the equivalent of about 1,600 km for a human being. It is clear that, even for distances considerably less than 13 km, the round dance would not be much use. If the discoverer of a new food source informed the other bees to go out and search in all directions for over several kilometres, they would never find the flowers. Thus, when a bee finds food at a considerable distance, say over 100 metres from the hive, she returns to the hive, offers the honey she has found, and then performs a different kind of special dance. She dances along in a straight line for a certain distance, wagging her tail vigorously and buzzing away by means of slight vibrations of the muscles that flap her wings in flight. At the end of this wagging run, she stops buzzing and wagging her tail, circles round to one side back to where she started, does another wagging run, circles round to the opposite side, does a third wagging run and so on. This sequence of movements is called ‘tail-wagging dance’. Showing special interest in wagging runs, a number of other bees follow her round. It is known that bees cannot hear sounds in the air, however they can feel the buzzing vibrations through the surface on which the dance is performed. Like the round dance the ‘tail-wagging’ dance tells the followers of the dance that there is food available, and what flowers to look for, from the smell. But it tells them much more than this; it tells them precisely how far away the flowers are, and in exactly what direction. And so, the bees who study the dance can fly with precision to the spot indicated, even at a distance of kilometers, and find the honey-bearing flowers.
The distance to the food is conveyed by the tempo of the dance. A quick-step tempo means a relatively nearby food source, a slow tempo means a more distant one. More precisely as the distance increases, so does the duration of each wagging run. The bees who follow the dance study several wagging runs and then appear to calculate the average duration which they then translate into distance by a mathematical rule.
The ‘tail-wagging dance’ is sometimes done on a horizontal surface just outside the hive. When this happens, the dancer indicates the direction of food by aiming her run in exactly the direction of the food. She can do this if she can see the sun (or the polarized light of the blue sky, which indicates the position of the sun to bees, though not to us). So, actually she is taking up a position in which she sees the sun as the same angle as during her flight to the honey source. The wagging run makes the same angle with the sun on her outward flight did. But the dance is normally performed in the dark inside the hive, on the vertical surface of the honeycomb. Here the angle between the flight path and the sun is translated into the angle between the wagging run and the vertical direction straight upwards.
Another remarkable fact about the bees communication is that if the bee reached her goal (and returned from it) by an L-shaped detour, she uses the angles and lengths of the two sections of flight to calculate the true direction of the goal by straight-line flight, and this is the direction she conveys in her dance, even when she did not this direct route herself.
As for the bees who are following the dance, they are working literally in the dark and can only use touch to find out the angle of the dancer’s wagging run against the vertical. They translate this back into a visual angle with the sun, fly off in this direction for the distance signaled by the wagging run tempo, and look for the flowers of the scent they smelt on the dancer.
So far we have described the language of the Carniolan race of honeybees according to the findings of Frisch. Other races have different ‘dialects’. German, North African, Caucasian, Italian honeybees all indicate distance and direction by much shorter dances than the Carniolans. How the honeybees have learned to communicate with each other is certainly remarkable! However, it is not a true language, because the system used by bees, unlike human languages, cannot generate new combination of structures and symbols to describe novel events. One example of their limitation is that bees appear to have no way of communicating height or depth beyond a few meters. Thus, if you take a bee to a source of food in a place, say 10 metres above ground level, she will return to her hive and try to indicate the food source by means of her dance. Then, the other bees will all fly out in the direction she indicated, but they will never find the source. No matter how near the source is, even if it is just above the hive, the result will be the same.