Since the 1950s, we've known that honeybees making a "whoop" sound. But what the sound means has been up for debate. Early studies linked it to a request for food, but other studies suggested the sound was a way of telling other bees to stop foraging in certain areas.
The truth turns out to be something more mundane than either of the earlier hypotheses: It's just a sound of surprise.
Researchers from Nottingham Trent University in the United Kingdom used accelerometers to record vibrations inside actual hives for a year. They then created software to identify and isolate the sound, which you can hear in the clip below.
The researchers found that the whoops happened much more frequently than we thought, far more frequently than would be required for food or to warn each other about foraging areas. Instead, using cameras trained on the hives, the researchers found that the whoops happen mostly at night when the bees bump into one another. It's a sound of being startled by something going buzz in the night.
Martin Bencsik, who led the study, suggests a standardized stimulus applied to a hive equipped with accelerometers could give us new insights into the hive's health now that we understand the whoop better. "I would imagine an unstressed colony would have less of a response and a colony that’s very stressed would be very reactive to a small stimulus," Bencsik told New Scientist.