Study

Group decision making in swarms of honey bees

Seeley, Thomas D.; Buhrman, Susannah C.

Behavioral Ecology and Sociobiology, 1999

Peer-reviewedfield observationwild

What they did

Every scout bee on three swarms was individually marked, and all dances performed on the swarm surface were recorded continuously from the swarm forming until it flew, so that the full record of which sites were advertised, by whom, and for how long could be reconstructed.

Studied in: Apis mellifera
Sample size: 3 swarms with every scout bee individually marked and tracked

What they found

Scouts advertise a dozen or more candidate nest sites at first. Individual scouts dance for fewer circuits on each return and eventually stop, with the decline slower for better sites, and the swarm departs only once dancing has converged almost entirely on one location.

What it means

The authors' reading, and ours. Where they differ, that difference is the point.

How the authors put it

Nest-site choice is a decentralised competition between advertisements, in which the better site accumulates support because its recruits persist longer, not because anything compares the options.

How NatureHQ reads it

The mechanism is more interesting than a vote. No bee ever compares two sites; each simply advertises what it found and gives up at a rate set by how good it was. Quorum falls out of the arithmetic. This is the clearest available demonstration that a good collective decision requires no individual capable of making it, and it is the reason NatureHQ treats "the swarm decides" as a description of a process rather than a metaphor for a mind.

Limitations

Three swarms, in a single region, with an artificially constrained set of available cavities.
Marking and continuous observation may alter scout behaviour slightly.
Describes the dynamics; the neural rule producing the decay in dance vigour is inferred.