Their technique, says Cornell University biologist Thomas Seeley, includes coalition building until a quorum develops.
The Seeley group's study, which is published in the May-June issue of American Scientist, might well be used to help improve human group decision-making, he says.
Scientists had known that honeybee scouts "waggle dance" to report on food. Seeley and his colleagues, however, have confirmed that they dance to report on real estate, too, as part of their group decision-making process.
The better the housing site, the stronger the waggle dance, the researchers found, and that prompts other scouts to visit a recommended site. If they agree it's a good choice, they also dance to advertise the site and revisit it frequently. Scouts committed to different sites compete to attract uncommitted scouts to their sites, the researchers have discovered, but because the bees grade their recruitment signals in relation to site quality, the scouts build up most rapidly at the best site.
As soon as 15 or more bees are at any one site, the researchers found, the scouts signal to the waiting bees in the swarm that it's time to warm up their flight muscles in preparation for takeoff. Each scout does so by scrambling through the swarm cluster and briefly pressing its vibrating thorax against the other bees to stimulate them to activate their wing muscles. Once every bee has its thorax warmed to 95 degrees Fahrenheit, the swarm lifts off toward its new home.
"This is a striking example of decision making by an animal group that is complicated enough to rival the dealings of any department committee," said Seeley, a professor of neurobiology and behavior at Cornell and lead author of the article.