Clarifying Communications: The Round Dance vs. Waggle Dance Dichotomy is Misleading.

I’d been puzzling over the question of their being two parts to the waggle dance for some time because current beekeeping literature often refers to both round and waggle dances yet science tells us otherwise. This is confusing especially for students of the Bee Behaviour module, so I decided to investigate a little further and came up with this piece. This week’s blog is a version of an article recently published in BBKA News.

Communication.

We humans communicate with each other in so many different ways it is astounding really. We can use verbal communication and openly deliver our messages through speech, or we can write them down on paper. We can use covert, subtle, and nuanced signals to convey information about ourselves. Examples include: dressing in a particular way, polishing our shoes before a meeting, folding our arms across our chests in a defiant pose, or falling asleep during a Zoom meeting lolling across the sofa. Unconsciously, we can convey feelings of anxiety by perspiring profusely, or flushing red above the neckline; managers may recall interviewees sitting uncomfortably on the edges of their chairs with tightly clenched hands looking rather nervous.

Honey bees communicate many things through signals and cues, and so we and they are much alike in this respect. Also, human beings and honey bees share something special; we are the only animals that can tell one another the locations of importance resources, such as excellent sources of food.  We do this whenever we guide friends to an outstanding restaurant by giving them clear driving directions. Honey bees do this when they steer their hive mates to rich flower patches by performing waggle dances.

Today, most honey bee biologists acknowledge only two or three dances performed by honey bees including the waggle dance and the tremble dance. The waggle dance tells a nestmate the direction and distance to go to a rich food source (or water source, or home site) while the tremble dance activates resting receiver bees during a nectar flow when foragers find it difficult to get nectar unloaded on return to the hive.

Signals.

A signal ¹ is defined by scientists as a structure or behaviour that has been shaped by natural selection for the purpose of conveying information. The signals of honey bees have evolved to be easily detected inside the dark nest or hive, and these are mainly chemical and mechanical stimuli. Pheromones are chemicals secreted from exocrine glands that release odours to the outside of the body and give information to other individuals of the same species. Endocrine glands however, release chemicals into the bloodstream and give information to other organs in the individual’s body.

Honey bees possess at least 21 known signals, and over half are pheromones. These include the worker-produced Nasonov pheromone which functions to attract nestmates, and the queen-produced mandibular gland pheromone (QMP) which indicates the presence of a queen. Circulating QMP helps maintain colony cohesion by suppressing the building of queen cells.

Mechanical signals include the waggle and tremble dances, shaking signal — sometimes called the dorsoventral abdominal vibration signal, (the DVAV) — buzz run, grooming invitation, antennation signal and worker piping. There are two forms of worker piping; wings -together and wings- apart. We know that the message of wings-together piping is “warm up your flight muscles”². Queen piping, indicating the presence of a queen, is the only known queen-produced mechanical signal.

Cues.

Cues are information variables perceived by a bee that have not been shaped by natural selection to intentionally impart information; instead, cues convey information incidentally. An example of a chemical cue is the floral odour on a waggle dancer. It incidentally indicates the type of flower visited by the dancing bee. The floral odour cue comes about as a by-product of finding and foraging on the flower. Worker bees get information from different cues, some of which are chemical cues. There are also tactile cues, time cues (e.g., how long it takes a pollen collector to find an empty cell for her pollen loads), and visual cues.

New beekeepers and students of the modular examination systems are easily confused by out-of-date information such as the round dance telling foragers about food sources near the hive, vs. the waggle dance indicating sources further away. This article is the result of exploring the research and examining current evidence which shows that it is misleading to think that honey bees have two distinct recruitment dances; round and waggle. This piece of writing aims to raise awareness and enable beekeepers to better understand the waggle dance so that they can answer examination questions simply without having to add unnecessary and inaccurate frills.

Karl von Frisch.

Karl von Frisch won the Nobel prize for science with his discovery of the dance language of the honey bee. When von Frisch started studying honey bees in 1911, his research focused on testing the colour vision and olfactory abilities of worker bees.  It was when he was conducting tests for colour vision that he accidentally discovered what he called the round and waggle dances.

This discovery came in 1919, when he began studying the ability of the bees coming from an observation hive to recruit nest mates to a feeding station. Looking into his observation hive, he saw that the bees visiting his nearby sugar-water feeders performed round dances; he concluded that they were bees advertising nectar sources with round dances. He also saw that those bees returning with loads of pollen (from flowers in gardens around Munich) performed waggle dances. This correlation between dance form and forage type led him to think that round and waggle dances represent different types of forage, not different distances to flowers.  However, 25 years later he learned that round dances were for sources less than 100 metres from the hive, while waggle dances are used to indicate sources further away. In other words, he learned that round and waggle dances do not indicate different typesof food sources, and instead they indicate different distances to food sources.

Figure 1 Reproduced, with permission, from Following the Wild Bees, by Thomas D. Seeley. 2016.  Princeton University Press.

https://commons.wikimedia.org/wiki/File:Bee_waggle_dance.png

When a forager bee comes home excited by having found a patch of flowers brimming with nectar or pollen, she pushes her way to the hive and climbs onto a comb where she proceeds to run through the figure-of-eight pattern of a waggle dance to share her knowledge with unemployed foragers. She executes the waggle run of each dance circuit with great conviction, giving it special emphasis through the lateral vibrations of her body and the up-and-down buzzing of her wings. Then she turns to the right to circle back to the start for another waggle run and then, after completing that run, she turns to the left and circles back again to start another waggle run, and so on, again and again, alternatively making left and right turns after performing waggle runs.

The direction and duration of each waggle run correlate closely with the direction and distance to the flower source that the bee has just visited. If the flower source is located directly in line with the sun’s direction, then the bee indicates this by performing waggle runs pointing straight up on the vertical comb. But if the flower source is located at an angle relative to the sun’s direction, then the bee performs waggle runs at this angle relative to the direction of straight up on the comb. You can see an example of this in Fig. 1, where the flowers lie 40˚ to the right of the sun’s direction, and the dancing bee’s waggle run is correspondingly tilted at an angle of 40 ˚ to the right of vertical. The bee indicates the distance to the flowers in the duration of the waggle run. The further the flower source, the longer the waggle run. You can see in Fig. 1 that the waggle run lasting one second tells the other bees that they need to fly some 500 meters (0.3 miles) to find the treasure trove.

Slow Motion.

The waggle dance has fascinated scientists and the beekeeping world for many years, but it has taken modern technology to enable biologists to study and dissect this behaviour.  A Sony mini-DV camcorder that could play in slow motion and capture each stage of the dance enabled this recent discovery. What had been impossible to see with the naked eye became obvious from studying the video recordings of dancing bees played back in slow motion. This revealed that information about direction and distance to a food source is expressed in what have been called round dances. It is now clear that each circuit in a bee’s dance contains a waggle run that provides direction and distance information, even when flowers being announced are nearby³.

Further experiments showed that when a feeding station is only 20 meters from a hive, the dances that advertised this food source guided the dance followers to the right location. For example, if the advertised feeder is to the east, most of the recruits go to this feeder rather than to an identical feeder 20 meters to the west. It is now clear that it makes sense to say that honey bees have one adjustable dance; the waggle dance. The dichotomy of round dances vs. waggle dances is an artefact of the technology available to Karl von Frisch when he studied how honey bees recruited nestmates to rich food sources, back in the 1920s.

References:

¹ Seeley TD (1998) Thoughts on Information and Integrations in Honey Bee colonies, Apidologie 29 (1998) 67-80

² Seeley, Thomas D. (2010) Honeybee Democracy (page 154), Princeton University Press, New Jersey.

³ Gardener, K., Seeley, Thomas D. & Calderone, Nicholas W. (2008) Do Honey Bees Have Two Discrete Dances to Advertise Food Sources? Animal Behaviour, 2008, 75, 1291-1300

Available online at www.sciencedirect.com