Unlocking the secrets of bee dance language – bees learn and culturally transmit their communication skills

A bee performs the wave dance in the center of this photo to communicate with its mates the location of a rich nectar source. Credit: Heather Broccard-Bell, CC BY-ND

The Greek historian Herodotus reported over 2,000 years ago a botched forbidden experiment in which two children could not hear human speech so that a king could discover the true, unlearned language of humans.

Scientists now know that human language requires social learning and interaction with other humans, a quality shared by many animal languages. But why do humans and other animals have to learn a language instead of being born with that knowledge, like many other species of animals?

This question fascinates me and my colleagues and forms the basis of our recent paper published in the journal Science. As a biologist, I have spent decades studying bee communication and how it may have evolved.

There are two common answers to why language should be learned or innate. First, complex languages ​​can often respond to local conditions as they are learned. A second answer is that complex communication is often difficult to produce even when individuals are born with some knowledge of the correct signals. Since bees’ ways of communicating are quite elaborate, we decided to study how they learn these behaviors to answer this linguistic question.

What is waggle dancing?

Surprisingly, bees possess one of the most complex examples of non-human communication. They can tell each other where to find resources such as food, water, or nest sites with a physical “trembling dance.” This dance conveys the direction, distance and quality of a resource to the bee’s mates.

This video, from PBS Nova, shows bees performing their “dance.”

Essentially, the dancer points the recruits in the right direction and tells them how far to go by repeatedly circling around a figure eight pattern centered around a flicker, in which the bee shakes its belly as it moves forward. Dancers are stalked by potential recruits, bees who follow the dancer closely to learn where to go to find the communicating resource.

Longer wave paths communicate longer distances and roll angle communicates direction. For higher-quality resources, such as sweeter nectar, dancers repeat the waggle run more times and return faster after each waggle run.

Making mistakes

This dance is difficult to produce. The dancer not only runs – covering about one body length per second – while trying to maintain the correct swing angle and duration. It is also usually in complete darkness, among a crowd of bees that are scurrying about, and on an uneven surface.

Therefore, the bees can make three different types of mistakes: pointing in the wrong direction, signaling the wrong distance, or making more mistakes in performing the figure-eight dance pattern—what the researchers call disruption errors. The first two mistakes make it harder for new recruits to find the shared location. The disruption bug can make it harder for recruits to follow the dancer.


Unlocking the secrets of bee dance language - bees learn and culturally transmit their communication skills

The waggle dancer gives the directions and followers learn where to find the indicated resource. Credit: Dong Shihao, CC BY-ND

Scientists knew that all Apis mellifera honeybees only start foraging and dancing as they get older, and that they also follow experienced dancers before they first attempt to dance. Could they learn from experienced teachers?

A “forbidden” bee experiment

My colleagues and I thus created isolated experimental colonies of bees that could not observe other waggle dances before waggle dances themselves. Like the ancient experiment described by Herodotus, these bees could not observe the language of the dance because they were all the same age and had no older, experienced bees to follow. In contrast, our control colonies contained bees of all ages, so the younger bees could follow the older, experienced dancers.

We recorded the first dances of bees living in colonies with both population age profiles. Bees that could not follow the dances of experienced bees produced dances with significantly more direction, distance, and disorder errors than the dances of the novice control bees.

We then tested the same bees later when they were experienced foragers. The bees that did not have teachers now produced significantly fewer directional and misdirection errors, possibly because they had more practice or had learned by eventually following other dancers. The dances of the older control bees from colonies with teachers remained as good as their first dances.

This video, from the Nieh lab, shows the “running wave” of bees.

This finding told us that bees are therefore born with some knowledge of how to dance, but can learn how to dance even better by following experienced bees. This is the first known example of such complex social learning of communication in insects and is a form of animal cultivation.

Dance dialects are about distance

A mystery remained in relation to the bees who early on had no dance teachers. They could never correct their mistakes at a distance. They continued to overshoot, communicating longer distances than normal. So why is this interesting to scientists? The answer may lie in how remote communication could be adapted to local conditions.

There can be significant differences in where food is distributed in different settings. As a result, different bee species have evolved different “dance dialects”, described as the relationship between the distance from a food source and the corresponding duration of the waggle dance.

Interestingly, these dialects vary, even within the same bee species. The researchers suspect that this variation exists because colonies, even of the same species, can live in very different environments.

If language learning is a way of coping with different environments, then perhaps each colony should have a dialect remotely adapted to its location and passed from experienced bees to novices. If so, our individual bees deprived of the teacher may never have corrected the distance errors because they acquired, on their own, a different dialect of distance.

Normally, this dialect would be learned by experienced bees, but it could potentially change within a single generation if their environmental conditions changed or if the colony crowded into a new location.

In addition, each colony has a “dance floor,” or the space where the bees dance, with complex terrain that dancers can learn to better navigate over time or by following the steps of older dancers.

These ideas remain to be tested, but they form the basis for future experiments investigating cultural transmission between older and younger bees. We believe that this study and future studies will expand our understanding of collective cognition and language learning in animal societies.

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Reference: Unlocking the secrets of honeybee dance language—bees learn and culturally transmit their communication skills (2023, March 11) retrieved March 11, 2023 from https://phys.org/news/2023-03-secrets-honeybee -languagebees-culturally-transmit.html

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