Background Essay: Bee Navigation
In a healthy hive, the hum of infertile female worker bees is incessant. And while all of this activity may seem frenetic, it's anything but random. Every worker has a job to do, determined by which of the three life stages she is in. Each adult life stage is characterized by the specific set of tasks that occupy the bee during that stage. Young workers (1 to 12 days old) clean cells, nurse the brood, and tend the queen. Middle-aged workers (12 to 20 days old) build the comb, store nectar and pollen brought by forager bees, and help maintain the temperature of the hive. At about the age of 20 days, workers begin to travel regularly outside the hive as foragers, collecting the nectar and pollen that sustain the colony.
Many of the honeybee's behaviors are innate. Young workers know automatically when and how to care for the eggs and the developing pupae. Likewise, bees appear to interpret and respond automatically to the "waggle dance," the language foraging bees use to tell other bees in the hive where to find food. Foraging bees instinctively know to fly a course that is the same number of degrees to the right or left of the sun as the dancing bee's orientation relative to vertical. But despite the innate behaviors that guide the actions of bees within a colony, it appears that experience plays an important role outside the hive -- and this may explain, at least in part, why only the oldest bees do the foraging for the colony.
According to a recent study, young worker bees make dozens of "orientation flights" long before they begin foraging for nectar. In this way they are able to learn the lay of the land before having to put this knowledge to use while searching for food. Researchers in England followed the activities of young honeybees tagged with tiny radar transponders. (The little antennae that the scientists attached to the backs of the bees weighed less than the average load of pollen bees carry.) The study found that non-foraging-age bees -- those younger than 20 days -- began with short flights outside the hive but, over time, increased the distances they flew, ultimately flying as many as five kilometers from the hive in a single flight.
This pattern suggests that bees learn the features of the landscape around the hive in a progressive fashion. By making multiple flights to and from the hive, bees view the hive and landmarks from many different directions. This knowledge, researchers believe, may be crucial to the bees' effectiveness as foragers, both in interpreting the dances of their hivemates and in providing information about food sources they've found to their hivemates.