March 3, 2006 — Enormous bee swarms containing as many as 15,000 bees are guided by "streaker" scout bees that fly super fast and lead the swarm to its destination, according to a new study published in the latest journal Animal Behavior.

The study negates a prior theory that scout bees released smelly chemicals that informed the other bees where to go. The discovery of streaking scout bees indicates the other bees simply look up to the speedy flyers that zip along with a "Follow me!" visual cue.

"A bee's eye is rather large and is not placed at the front of the bee's 'face' like ours, but is sort of positioned on top of the bee's head," explained Madeleine Beekman, lead author of the study. "This means that the bee has a clear view of what is happening above her."

Beekman, a bee expert and researcher in the School of Biological Sciences at the University of Sydney, added, "Hence, when scouts fly fast above a bee that doesn't know where to go, this fast-flying bee will be visible as a streak and this streak points into the direction of travel."

She told Animal Planet News that the streaks are even visible to humans; she has seen them by walking into bee swarms. The fastest streakers fly at a rate of around 3.3 feet per second.

Funded by the Australian Academy of Sciences, Beekman and her colleagues studied honeybee swarms at Cornell University in New York. Bees do secrete pheromones that other bees can smell, so the researchers sealed these odor-releasing glands on the test bees to see if that would prevent the swarm from finding its way.

In the spring, large bee colonies of around 20,000 to 30,000 bees usually divide into two groups. One stays at home with a daughter of the queen, who then becomes queen. The original queen and the rest of the bees then leave in a massive cloud to form a new colony.

Scout bees, which comprise about five percent of the swarm, negotiate among themselves via dance communication as to where the new home will be located.

Beekman and her team photographed such bee swarms on the move. The sealed glands did not deter the scouts, which seem to operate as independent agents once the swarm takes flight.

"They (the streaker scouts) do not seem to move en masse," she said. "Instead, we think that an individual flies over the swarm, exits the swarm and then either waits for the swarm to catch up again or circles back to re-enter the swarm from behind. By not flying en masse, the scouts ensure that there will always be bees streaking and thus guiding the swarm."

Iain Couzin is a Royal Society university research fellow at the University of Oxford and an expert on collective behavior of ant, bee and locust swarms, fish schools, bird flocks, and even human crowds.

He told Animal Planet News, "Understanding how animals communicate is a fascinating topic and honeybee migration is a beautiful example of how a few informed individuals (scouts) can guide a large number of naive individuals."

Couzin suggested that other insects and animals could benefit from a similar system.

He said, "Honeybee migrations provide an important insight into how relatively simple organisms can communicate collectively, creating a type of swarm intelligence."