December 1, 2020

I, Science

The science magazine of Imperial College

Andrew Purcell

Ever since French entomologists August Magnan and  André Sainte-Lague famously declared that bee flight was aerodynamically impossible, a popular myth has prevailed that the phenomenon of bee flight is beyond our current scientific capabilities to explain. In fact, it was beyond our reach for over 70 years. However,  in 2006 a team of researchers from Caltech University were able to unlock the secrets of bee flight through careful study of slow motion imagery.

The researchers found that bees’ wings beat inordinately fast compared to their large body size. Usually, smaller insects have wings which beat faster, because smaller body sizes are generally less aerodynamic than larger ones. However, bees’ wings beat 230 times per second, whereas fruit flies, only around one eightieth of the size of a bee, beat their wings at a rate of only 200 times per second. The reason bees are able to beat their wings so unusually fast is because of the peculiar design of their flight muscles. In normal flight, bees’ wings only move through an arc of around ninety degrees, which is much less than most other insects. It is this adaptation which allows bees to beat their wings fast enough to get their large bodies up off the ground.

Another interesting peculiarity of bee flight is that bees don’t actually increase the speed of their wing beat when carrying large quantities of nectar or pollen as one might expect. Instead, they increase the arc through which their wings beat in order to give them more power. This has led scientists to speculate that bee flight muscles may have evolved from ancestral flight muscles very different to those of other insects and that, as a result of this, they are forced to beat their wings at a constant frequency.

Did you know? Bumblebees have four wings; the two rear wings are small and are usually attached to the fore wings by a row of hooks called hamuli.