Robyn Lang, of Woolston School, asks :-

How fast do bumblebee wings flap and how can it fly when it is so fat?

Simon Pollard, a zoologist at the Canterbury Museum, responded.

Bumble bees fly because they use their two pairs of wings like the rotary blades of a helicopter, rather than just flapping them up and down. If they just flapped their wings they would never get off the ground. It is an amazing feat of bee design that their small wings can beat fast enough for the bee to fly. In fact, their small wings beat at nearly two hundred times a second or twelve thousand times a minute.

The power that is applied to the wings to make them beat so fast comes from muscles in the bee's thorax; the part of the bee's body where the wings are attached. The thorax is full of flight muscles, and, like a high powered engine, it requires a lot of fuel to keep them working. For a bumblebee, sugar is fuel.

Given the size of a bumblebee's body, it is not surprising that 90 per cent of the calories it burns are from its flight muscles. Like an engine, the bee's thorax generates heat, and if the bee did not have an efficient cooling system it would over-heat. Bumblebees also need to keep their flight muscles above 30 Celsius or they will not work. So, the ability of the bumblebee to regulate their temperature is very important.

Sometimes, bumblebees run out of fuel and you will find them walking around on the ground. If you give them a mixture of one-third sugar and two-thirds water, they should be able to refuel and take off.