How bees communicate and find their way

The waggle dance

A returning forager runs in a straight line across the vertical comb face, vibrating her abdomen rapidly, then loops back to the start and repeats — tracing a figure of eight. Two variables are encoded in that straight run.

• Direction. The angle of the run relative to vertical corresponds to the angle of the food source relative to the sun. Straight up means fly towards the sun; 60 degrees to the right of vertical means fly 60 degrees right of the sun. The dance translates a horizontal bearing into an angle on a vertical surface, using gravity as the reference.
• Distance. The duration of the waggling portion corresponds to how far away the food is. Longer waggle, further flight.
• Quality, indirectly. A richer source produces a more vigorous and more repeated dance, so better sources recruit more bees.

Karl von Frisch worked this out over decades and shared a Nobel Prize for it in 1973. It remains one of the most surprising results in animal behaviour: a small-brained insect transmitting an abstract, symbolic representation of a location it cannot see.

Navigation

A forager may fly several kilometres and return to a specific hive among many. She does it with several systems at once.

• A sun compass, corrected for time of day. A bee held in the dark for hours will dance with the angle updated for where the sun has moved to — she is running an internal clock against the sun's path.
• Polarised light. Bees see the polarisation pattern of the sky, which lets them find the sun's position through cloud.
• Landmark memory. Foragers learn visual features along a route and around the nest entrance, which is why moving a hive a short distance strands the flying bees at the old location.
• Optic flow for distance. Distance is judged by how much visual texture streams past on the way, not by time or energy used — which is why a bee flown down a narrow patterned tunnel will report a much longer distance than she travelled.

Deciding as a group

The most striking use of the dance is not finding food but choosing a home. When a colony swarms, it hangs in a cluster while scouts search for a new nest site and return to dance for the ones they found. A scout who has seen a good cavity dances longer and more insistently; one whose site is mediocre dances briefly and then goes to inspect a rival's.

Over hours, support consolidates. When enough scouts are visiting one site — a quorum, rather than a majority — the swarm takes off and flies there. Nobody has compared the options; each scout knows only one site, and the decision emerges from the aggregate. Thomas Seeley's work showed swarms reliably choosing the objectively best cavity available.