Dance language

Western honeybees waggle dance

The dance language is one of the honeybees' essential forms of communication . Through dancing, several types of information are conveyed , including about sources of food ( traditional sources ).

Starting position

About 5% of the flying bees are so-called scouts . These have the task of looking for new sources of food in unknown areas . This part, which is associated with numerous dangers , is only assumed by those bees that are already at the end of their life expectancy and whose loss no longer poses a great risk for the beehive . The majority of the foragers remain waiting in the hive in the event that a new source of food has been found that needs to be processed quickly.

If such a scout was successful in her search, she hands over what she has harvested, for example the nectar she has collected , to mates when she returns . Did this a sufficient quality and there is demand in the hive, the scout of these will Vorkosterbienen excited by energetic sensor contacts to notify the waiting collectors with the location of their prey, which is the case in approximately 10% of the returning scouts.

This is done through so-called dances, in which the bees perform striking and characteristic movement patterns in the hive, which give the dances their name.

Even when swarming, auditioning plays a crucial role in finding and selecting a suitable new nesting site. When a bee colony wants to multiply, a swarm of bees is created .

Information content

With these dances, the waiting foragers are given four different pieces of information about the raw material source:

• the general fact that resources were found in sufficient quantities and the request to collect them there as well;
• the type of raw material found (by smell and taste);
• Productivity and quality of the source (per intensity of the dance);
• the location of the site as seen from the stick (using distance and direction information, only when wagging ).

The dances are the same for all raw materials collected by flying bees apart from minimal differences; most often, however, such a movement indicates a source of food (e.g. nectar, pollen , honeydew or water ).

Dance forms

Depending on the distance of the sources of feed or raw materials, a find is indicated by different dances. For springs in the immediate vicinity of the hive (up to approx. 100 m) the round dance is mainly used , for all springs located further away the bees use the waggle dance . The dances always only give one (but quite precise) target area, in which the bees orientate themselves mainly on smells as soon as they have reached it.

Round dance

The round dance represents the simpler and historically probably older, but also the more imprecise form of the two primary types of dance. The place where the food was found is not specified, the foragers only learn that the source is in the immediate vicinity of the beehive.

In the round dance, the bee walks around in a small circle ( radius approx. 1–2  cm ) for up to 3 minutes and changes its direction of rotation after about one complete turn. She attracts the attention of other collectors (mostly 2 to 3 individuals), who now stay with their feelers as close as possible to the abdomen of the dancer and follow her rapid movements. The trailing foragers perceive the smell of the visited plant through the close feel of the antennae . Occasionally the dancer chokes out additional nectar drops, which the night dancers lick off and thus experience the taste.

After the end of the dance, the night dancers go purposefully in search of food, mainly orienting themselves on the basis of the smell communicated to them.

Before the scout sets out to search again for a new location, she repeats her dance at two to three other places on the floor, where the information is also passed on to waiting animals. If they return to the source after their flight, they pass on the location in the same way as the original discoverer, until the feed location is completely exploited or there is no longer any need.

Waggle dance

If the food or resource sources are further away from the hive, the type of information transmission changes when the bees return.

In order to ensure that a location can be found again as quickly and efficiently as possible in the building's catchment area, which can measure up to several kilometers , its spatial location must be specified much more precisely than just its rough distance . This is done by the so-called waggle dance .

Emergence

Bee research now assumes that the waggle dance was initially not used primarily for looking for food, as it is today, but initially for swarming (reproduction of a colony). The sources of food were probably given exclusively via the round dance. When swarming out, possible new nesting sites on the so-called bee cluster are indicated with a waggle dance, which, however, unlike when searching for food, takes place horizontally. Since not only the life of an animal but of the whole people is at stake here, and in addition a nesting site has no scent or other easily perceptible features, it is only logical that the location must be given very precisely. Presumably, due to the advantages of this precise information system, this dance has also established itself in the search for food, but without completely displacing the round dance.

procedure

Interpretation of the waggle dance

As with the round dance, the food taster first decides whether the bee that has returned home should inform others of what it has found. If this is the case, the latter begins - usually around the middle of the stick - with its characteristic movements in order to disseminate the information. This following dance consists of the circular run and the tail run . During the tail run, the bee initially runs a few centimeters straight ahead with violent lateral vibration of the abdomen (wagging). Then it returns in an arc to the starting point of the tail run. From there the tail run begins again, which is followed by the circular run, but now in the opposite direction. As with the round dance, the dancer is followed by three to four foragers, who arrange themselves in such a way that they can easily register the dancer's wagging movements with their antennas.

Decisive are the sounds emitted by the dancer in impulses, without which the other collectors would not follow. These signals have a frequency of 240–260  Hz and are transmitted at an enormous volume of approx. 110  dB during the tail run. However, bees can only hear this noise a few centimeters away on the same honeycomb, as most of the sound is emitted vertically instead of horizontally from the wings, creating a bell in which the volume decreases laterally by the third power . This sound is produced by the bee with its flight muscles, which are in a kind of idle state. The sound frequency therefore corresponds to the average wing beat frequency. Western honey bees react with their hearing to the so-called speed of sound ( oscillation speed of the air molecules ) while other animals or z. B. People respond to the sound pressure (pressure fluctuations in the sound medium). That is why the number and sequence of sound pulses is more important than their length or frequency. The sequence of the sound impulses is not dependent on the frequency of the wagging.

In addition to the sound impulses in the air, vibrations with the same frequency are transmitted through the wax of the honeycomb during the tail run. Sometimes people speak of the wagging position instead of walking, as the insect has very stable contact with the honeycomb for most of the time.

Location

The location is indicated by two attributes that can be measured by bees without great effort. On the one hand the distance to the stick and on the other hand the direction to the source as seen from the stick ( polar coordinates ).

The distance is determined based on the energy required for the flight and the optical flow experienced during the flight . The optical flow describes the frequency of the abrupt changes in the appearance of the environment (e.g. transition between pasture and forest). The animals' energy expenditure is measured by the food absorbed ( consumed ) during the flight with the help of receptors in the honey bladder. The bee determines the distance from these values ​​and translates this into a specific dance tempo when it returns.

The more revolutions the animal makes per unit of time, the closer the source of food is. With increasing distance from the beehive to the food source, the bees waggle more violently in the middle part of the dance and the waggle dance consequently takes longer.

The direction to the feed location is always given relative to the position of the sun . This also works in cloudy weather , the position of the sun is perceived by the animals through the clouds based on the polarization direction of the light in the sky . In the rare but simpler case that the bees dance on a horizontal surface, the dance's tail run points directly in the direction of the food source. The flying bees waiting there can immediately take over the angle to the sun.

When looking for raw materials, however, dances on a horizontal surface are a rarity. The information transfer normally takes place vertically in the dark of the building . Here, a tail run pointing directly upwards represents a source in the direction of the sun, a rotation of the run through an angle α stands for a flight direction around α against the position of the sun. The animals recognize where exactly is in the hive by means of gravity and the earth's magnetic field. Even if the stick is artificially tilted up to approx. 15 ° to the horizontal, the animals can provide precise information.

The directions of the dances always refer to the horizontal. Information about the altitude of a source is not transmitted by the animals because the main food suppliers such as B. Flowers always appear near the ground. Blocks an obstacle such as If, for example, a mountain ridge is the direct route to a source of food, the insects do not indicate the route they have flown, but rather transmit the direct direction to this place, which is an enormous cognitive achievement. The following bees first fly over the obstacle in a straight line. As soon as you know the area, you will find a better or easier way yourself.

accuracy

In level and fan tests, it was shown that the majority of the collectors also look at the specified location. The existing deviations result on the one hand from the fact that each bee interprets the information given to it individually and on the other hand from external factors. So z. B. find another, more rewarding source of food in front of the specified location.

Recent research shows that the precision of the signal transmission during wagging can be impaired by sleep deprivation and thus by fatigue of the bees.

Since the dance movements only contain rough target information, but recruits arrive precisely at the new target for which the dancers advertise, the question arises how an imprecise input (the dance) can lead to an exact result (the arrival at the target). This problem solves when one understands dance as just one link in the chain of behaviors that are not confined to the beehive but are continued outside in the field. Honeybees also behave socially outside the hive. There is also interaction and communication in the field.

exploration

The bee dance was already described by Aristotle . The first further investigations were carried out much later by the behavior researcher Karl von Frisch around 1920. At that time, von Frisch was not yet aware that the waggle dance contained information about the direction and distance of a food source. He was of the opinion that the waggle dance can only be performed by pollen collectors and the round dance only by nectar collectors. According to von Frisch, the main task of the dance was to convey the smell of food and to announce an abundant source of food.

Only a change in the experimental structure of his feeding experiments 20 years later enabled him to decipher the waggle dance. In 1944 and 1945, von Frisch began to offer feed at a distance of more than 100 m, which caused all foragers, whether nectar or pollen collectors, to waggle. In 1973 he received the Nobel Prize for deciphering dance . In the meantime it has also been possible to imitate the bee dance with a robot and thus send the bees off in a certain direction.

More recent research has been able to identify individual substances from the group of alkanes ( tricosane and pentacosane ) and alkenes ( tricosene and pentacosene ) as semiochemicals ( messenger substances ) by using gas chromatography with mass spectrometry coupling .

It was previously believed that a worker who had to walk a long distance would be more exhausted on arrival than a bee who found food nearby, which is why the dance is performed less intensively. According to research by Jürgen Tautz ( University of Würzburg ), this information is now outdated. The bees then register the movement patterns of the images passing by in flight. The flight over monotonous routes (fields) is interpreted as shorter than the flight e.g. B. between dense trees.

Many species of insects are able to orient themselves by the position of the sun and maintain a certain direction by moving at a certain angle to the sun. In ground beetles it has been shown that they orient themselves to the vertical in the absence of light. To do this, they were placed on a tiltable horizontal surface. If they walked in a certain direction, the light was switched off and at the same time the base was tilted vertically. The beetles changed their direction and continued to run at the same angle to the vertical that they had previously kept to the light source.

The ability to form a connection between the sun and the angle to the vertical seems to be more widespread among them. In order to investigate whether this connection also exists in bees, a light source was installed in the normally dark beehive. Then the direction of the waggle dance was indicated relative to the light source. If the eyes of a returning worker bee were taped with shellac so that it could not see the lamp, it would orient itself on the vertical. All other bees interpreted the dance relative to the light source - and flew in the wrong direction.

Probably the waggle dance was originally performed in front of the stick and the actual direction to the sun was given. Later it was moved inside the stick, making use of the existing ability to reorient.

The question of the uniqueness and significance of the waggle dance is the subject of ongoing research. The inaccuracy of the dances was documented, for example, in a work by Tanner and Visscher from 2010. In a study in 2020, “dialects” of the dance language were described.

Due to the polarization of the light, which can also be perceived by the human eye ( Haidinger tufts ), the bee is able to make out the angle and thus dance. The sensory cells necessary for this are located in the bee's eye. If it is aligned to the maximum of polarization, this cell is also maximally excited. So the bee can memorize the coordinates. The time shift, which also causes a shift in polarization, makes up for the bee with its good time memory. For this realization, the Nobel Prize was awarded to Karl von Frisch in 1973 .

literature

• Karl von Frisch : About the "language" of the bees. In: Zoological yearbooks: Journal for systematics, geography and biology of animals. Department of General Zoology and Physiology of Animals. Vol. 40, 1923, pp. 1-186, ISSN  0044-5185 .
• Karl von Frisch: The dance language and orientation of bees. Belknap Press of Harvard University Press et al., Cambridge MA et al. 1967.
• Thomas Dyer Seeley : The wisdom of the hive. The social psychology of honey bee colonies. Harvard University Press, Cambridge MA et al. 1995, ISBN 0-674-95376-2 .
• Fred C. Dyer: The biology of the dance language. In: Annual Review of Entomology. Vol. 47, 2002, pp. 917-949, ISSN  0066-4170 . (PDF; 284 KB) .
• Karl von Frisch : Dance language and orientation of the bees. Springer, Berlin-Heidelberg-New York, 1965, 578 pp. (PDF; 22 MB) , ISBN 3-642-94917-7
• Wolfgang Wittekind: Experimental triggering of dances in the honey bee . In: Natural Sciences . Vol. 42, H. 20, 1955, pp. 567-568, ISSN  0028-1042 .
• Ulrich Sommermann: The dance language of the bees in worksheets insects , Ernst Klett Verlag, Stuttgart 1989, ISBN 3-12-030920-6

Web links

Commons : Dance language  - collection of images, videos and audio files

• Scientific film document: "The dances of the bees" by Karl von Frisch from 1949 ( B / W , no sound)
• Video: Karl von Frisch: The language of bees . Institute for Scientific Film (IWF) 1926, made available by the Technical Information Library (TIB), doi : 10.3203 / IWF / C-4 .
• The symbolic communication of the bees

Individual evidence

1. ↑ Badische-zeitung.de , October 23, 2015: Bees “fly” to partners from their own country  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
2. ↑ Barrett A. Klein, Arno Klein, Margaret K. Wray, Ulrich G. Mueller, Thomas D. Seeley: Sleep deprivation impairs precision of waggle dance signaling in honey bees. In: Proceedings of the National Academy of Sciences . Vol. 107, No. 52, December 28, 2010, ISSN  0027-8424 , pp. 22705-22709, doi : 10.1073 / pnas.1009439108 , PMID 21156830 .
3. ↑ Jürgen Tautz: The exploration of the bee world. New data - new knowledge. Klett MINT Verlag 2015. To the book chapter "Bienentanz"
4. ^ Corinna Thom, David C. Gilley, Judith Hooper, Harald E. Esch: The scent of the waggle dance. In: PLoS Biology . Vol. 5, No. 9, September 2007, p. E228, doi : 10.1371 / journal.pbio.0050228 , PMID 17713987 .
5. ↑ Communication of bees: waggle dance disenchanted. On: süddeutsche.de from May 17, 2010.
6. ↑ David A. Tanner, P. Kirk Visscher: Does Imprecision in The Waggle Dance Fit Patterns Predicted by The Tuned-Error Hypothesis? In: Journal of Insect Behavior. Vol. 23, 2010, ISSN  0892-7553 , pp. 180-188, doi: 10.1007 / s10905-010-9204-1 .
7. ↑ Patrick L. Kohl et al .: Adaptive evolution of honeybee dance dialects. In: Proceedings of the Royal Society B. Online publication from March 4, 2020, doi: 10.1098 / rspb.2020.0190 .
   Bees dance in dialect. On: idw-online.de from March 4, 2020.