How bees fly!

There’s a myth I’ve heard a few times, that bees shouldn’t be able to fly as their bodies are too big for their wings. Obviously, this isn’t the case as we see bees flying all of the time, so what’s going on?

This myth is so pervasive that it’s the opening shot of “The Bee Movie” from 2007…but in all honesty that doesn’t surprise me as that movie gets so much wrong about honeybees, the main thing being that all the workers are female, not male as depicted in the film! But the wording from the film does highlight where this myth may go wrong as it states: “according to all known laws of aviation…” which normally would refer to planes and helicopters. Unlike planes, bees flap their wings in order to fly as opposed to using forward momentum (although the idea of a bee keeping its wings fixed and just running really fast to take off is amusing!). However, even with flapping wings, there is a long held belief that bumblebees in particular have too little wing area compared to their body mass to be able to achieve flight.

(picture caption: the ‘Manchester Bee’. A symbol of Manchester originating from the industrial revolution, representing a city built by workers. The Manchester Bee gained popularity following the 2017 bombing at the Manchester Arena).

One of the first things to know about bees is the number of wings: bees have 4 wings. This fact makes me very annoying as I like to bring up the point that the Manchester Bee is therefore technically a fly as it only has 2 wings, but a little artistic license is allowed I suppose. Flies are the order diptera (literally meaning two wings) whereas bees, wasps, ants and sawflies are from the order hymenoptera (meaning membrane wing) …you may think I’m getting sidetracked here, but I promise there’s a reason for this distinction! When bees are at rest, their wings are tucked along their backs and stacked on top of each other which makes them look incredibly small, enough so that the wing area looks like it shouldn’t be able to support their weight. In fact, bees have an incredible mechanism that allows them to keep their wings neatly tucked away when not in use but maximises the wing area in flight. A series of tiny hooks on the leading edge of the hind wing, called hammuli, slot into a groove on the trailing edge of the forewing allowing both wings to work together, rather than 2 separate wings. They essentially velcro their wings together when they need to fly and un-velcro them once they’re back on land.

Whilst the Velcro wing set up gives the bees flexibility to have either two compact wings or one large wing on each side, this isn’t the only trick they have up their sleeves. Bees consist of 3 body segments: the head, the thorax and the abdomen; the head is where most of the sensory organs are located: eyes, antennae, mouth. The abdomen is at the other end of the bee from the head and contains almost all of the organs. In the middle is the thorax, this is where the 4 wings and all 6 legs are attached to the bee and internally it is almost 100% muscle. The main flight muscles comprise of a set of vertical muscles and a set of horizontal muscles, somewhat confusingly called the ‘indirect flight muscles’. These work together to manipulate the thorax as a whole which in turn moves the wings. By moving the entire thorax, they can take advantage of the resonant frequency of their own bodies. This means that for every time they actively move their wings, they get several ‘free’ wing beats which helps the wings move up to 200-250 timers per second! The indirect flight muscles are only capable of raising and lowering the wings though, and while this may get the bee airborne it would struggle to control its movement through the air.

This is where the direct flight muscles come into play. These much smaller muscles operate to achieve the fine motor movements required for controlled flight, maintaining the correct pitch, yaw and roll that allows the bee to accurately fly from the hive and land on a flower of her choosing. The bee uses these muscles to angle the leading edge of her wings to move in a figure of 8 pattern, as if she were sculling through the air and it is this distinct motion that allows bumblebees to fly! If bees were to use their wings like birds do, only achieving lift with the down-beat of their wings, then they wouldn’t have enough wing area to sustain the flight, but by using this sculling motion they can generate lift with both the up-stroke and the down-stroke.

So next time you see a fuzzy buzzy bumblebee bumbling around the flowers, take a moment to appreciate the engineering marvel it has evolved in it’s wings to be able to achieve that bumbling flight!