By Scott Solomon, Rice University
As World War II was coming to an end in the summer of 1945, a professor named Karl von Frisch was making a discovery about the dance of honeybees that would later earn him a Nobel Prize. Von Frisch was fascinated by honeybees, and through a series of clever experiments, he would show that bees can communicate with one another through a type of interpretive dance.
Frisch’s earlier work had shown that honeybees have color vision. But now he was intrigued by the behaviors he was observing inside the beehive. The bees were kept in a narrow space with a pane of glass on the side, called an observation hive; a way developed by beekeepers to monitor the development of queen bees.
Frisch noticed that foraging honeybees, after returning to the hive, repeatedly shook their abdomens in consistent patterns. He believed the shaking, which became known as the waggle dance, was communicating some sort of information about sources of food the foraging bees had encountered.
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Pointing to the Food Source: The Distance
At first, Frisch assumed the foragers were letting the other bees know what kind of flowers they had found by shaking their abdomens to spread the scent of the flowers. To test this hypothesis, he marked individual bees with different colors of paint. He then placed baits with different types of food, like flowers or solutions of scented sugar water, in different locations and made note of which bees visited which bait.
To his astonishment, he observed that the bees changed their waggle dance depending on which food source they visited, but it wasn’t the type of food that mattered, but the location of the food source. A bee performing a waggle dance moves in a figure 8, waggling its abdomen during the middle portion where the two loops that make the figure 8 come together.
By carefully adjusting the location of each food source, Frisch figured out that the further away the food is from the colony, the longer the bee waggles before turning either right or left to complete the figure 8. What’s more, repeated experiments revealed that the information being communicated was precise: one second of waggling indicates a food source that is about 1 km away from the hive.
Pointing to the Food Source: The Direction
However, if a bee wants to visit that food source, it not only needs to know how far to fly but also in what direction. Frisch’s experiments showed that the angle at which the bees perform their waggle dance tells the other bees which way to fly when they leave the hive entrance. Specifically, the angle with respect to the vertical axis of the honeycomb corresponds to the angle with respect to the Sun that the bee should fly to find the food.
For example, if a bee waggles at 10° to the right of vertical, then the food can be found by flying 10° to the right of where the Sun can be seen in the sky from the nest entrance at that particular moment. Knowing the direction and the distance, the other bees in the hive have all the information they need to find the food.
But why do bees share this information with one another?
Survival in Numbers
Honeybees are social insects and the survival of any one bee is dependent on the survival of the colony. Honeybees are native to temperate climates with cold winters. But unlike many insects that live in cold climates, honeybees don’t go through a dormant state known as diapause, which is similar to hibernation.
To make it through the winter, the honeybees must keep their body temperatures above 50° Fahrenheit. They do this by producing heat with their wing muscles, contracting the muscles that raise each wing and the muscles that lower each wing at the same time. This muscle twitching doesn’t make the wings move that much but it generates heat in much the same way as shivering helps us to warm up a bit when we get cold.
An individual bee vibrating its wings isn’t enough to raise the surrounding temperature significantly, but when thousands of bees vibrate their wings in a small space, the heat generated is enough to keep all the bees alive throughout the cold winter months.
But all that muscle twitching burns energy, so the bees need a supply of high-energy food that is readily available inside the hive all winter long. That’s one of the most important reasons honeybees make honey—as a stockpile of food that will keep them buzzing inside the hive during winter.
Bees Need Space
The size of the hive is another important factor for the bees to survive the winter. They need enough space to accommodate all the worker bees as well as the honeycomb and the combs that the bees use to raise their larvae.
But if the space is too large, it won’t be possible to keep it warm with their vibrating wings. An average-sized bee colony, with its 44 pounds of honey, will need about 4 gallons of space, perhaps a bit more to allow room for expansion.
Beekeepers use artificial hives that are larger than what the bees need because the bees tend to fill the hive with as much honeycomb as they can, meaning there is extra that can be harvested. A single colony kept in a 36-gallon hive can make more than 220 pounds of honey in one summer!
Common Questions about the Why and How of the Dance of Honeybees
Through the waggle dance of honeybees, the foraging bees let other bees know how far a food source is and in what direction they should travel to find it.
Honeybees do their particular waggle dance to tell others how far a specific food source is and in which direction the others should fly to find it. The longer the distance is to the food source, the more a bee waggles; about one second for every one kilometer. The direction is communicated through the angle at which the bee dances.
Honeybees produce heat with their wing muscles, contracting the muscles that raise each wing and the muscles that lower each wing at the same time. When thousands of bees vibrate their wings in a small space, the heat generated is enough to keep all the bees alive throughout the cold winter months.