Environment

How Do Honeybees Locate Food?

Honeybees are highly social animals that live in hives. Inside the hive, a queen lays eggs that are cared for by workers. Besides caring for young and building and maintaining the hive, workers obtain food for themselves and other members of the colony by gathering nectar and pollen from flowering plants.

Biologists noticed that bees appear to recruit to food sources, meaning that if a new source is discovered by one or a few individuals, many more bees begin showing up over time. This observation inspired the hypothesis that food-finders have some way of communicating the location of food to others. How do bees “talk” to each other?

In the 1930s Karl von Frisch began studying bee communication by observing bees that built hives inside the glass-walled chambers he had constructed. He found that if he placed a feeder containing sugar water near one of these observation hives, a few of the workers began moving in a circular pattern he called a “round dance” on the vertical, interior walls of the hive. When he placed a feeder more than 100 m away from the hive, the bees moved in a similar pattern, but this time with straight runs down the middle accompanied by vigorous waggles of the abdomen. Von Frisch named this a “waggle dance”. Other workers appeared to follow the progress of the dance, first by touching the displaying bee as it danced and then by flying away in search of the food source.

To investigate the function of these movements further, von Frisch placed feeders containing sugar water at progressively greater distances from the hive. Using this technique, he was able to get bees to visit feeders at a distance of several kilometers from the hive. By catching bees at the feeders and dabbing them with paint, he could individually mark successful food-finders.

Follow-up observations at the hive confirmed that marked foragers

(1) danced when they returned to the hive, and (2) returned to the food source with unmarked bees.

To explain these data, von Frisch proposed that the waggle dance contained information about the location of food. Because beehives are completely dark, he hypothesized that workers got information from the dance by touching the dancer and following the dancer’s movements.

Three key observations allowed von Frisch to push our understanding of bee language further:

1. The length of the waggle run was proportional to the distance the foragers had to fly to reach the feeder.

2. The direction of the waggle run correlated with the direction of the food source from the hive.

3. The direction of the food source was communicated as relative to the current position of the Sun.

For example, if food is directly away from the Sun’s current position, marked bees do the waggle portion of their dance directly downward (Figure a).

However, if the food is 90 degrees to the right of the Sun, marked bees waggle 90 degrees to the right of vertical (Figure b).

These results are nothing short of astonishing. Honeybees do not have large brains, yet they are capable of symbolic language. What’s more, they are able to interpret the angle of the waggle dance performed on a vertical surface and to respond by flying horizontally along the corresponding angle.

Further work has confirmed that the dance language of bees includes several modes of communication: tactile information in the movements themselves, sounds made during the dance, and scents that indicate the nature of the food source.

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