New research from Michael Dickinson of the California Institute of Technology and his colleagues finally explains how Apis mellifera flies. Unlike other flying insects, honeybees use short wing strokes of less than 90 degrees and a high number of flaps every second to stay aloft. The researchers found that when challenged to fly in difficult conditions, such as a mixture of oxygen and helium that mimicked air density at more than five miles up in the atmosphere, the bees resorted to wider strokes but maintained the same high flapping frequency.
This means that honeybees are using a wing stroke pattern that is less efficient than the broader strokes and slower flapping of fruit flies and other insects, despite their constant foraging for food and other necessities. But it also means that a bee can generate more lift when it needs to--when it must carry a heavy load, for example. The researchers speculate that this odd set of strokes may have arisen from precisely this need, as the social creatures sometimes must fly while burdened with nectar or larvae. A report detailing the new findings is being published online this week by the Proceedings of the National Academy of Sciences.