Worker piping in honey bee swarms and its role in preparing for liftoff

Worker piping. previously reported only in hives, was observed in swarms as they prepared to liftoff to fly to a new home. Pipers are excited bees whi ch scramble through the swarm cluster, pausing every second or so to emit a pipe. Each pipe consists of a sound pulse which lasts 0.82+/-0.43 s and ri ses in fundamental frequency from 100-200 Hz to 200-250 Hz. Many, if not al l. of the pipers are nest-site scouts. The scouts pipe when it is time to s timulate the non-scouts to warm themselves to a flight-ready temperature (3 5 degreesC) in preparation for liftoff. The time-course of worker piping ma tches that of swarm warming; both start at a low level. about an hour befor e liftoff, and both build to a climax at liftoff. When we excluded pipers f rom bees hanging in the cool, Outermost layer of a swarm cluster, we found that these bees did not warm tip. The form of worker piping that we have st udied in swarms differs from the form of worker piping that others have stu died in hives. We call the two forms "wings-together piping" (in swarms) an d "wings-apart piping" (in hives).