Tuesday, 27 July 2010

Bumble

Bumble Bees are fascinating things. The fact that they can fly at all is a matter of some discussion and comes from an ability to create lift from both the down-stroke and the up-stroke of each wing beat. There are four wings in all, two large front wings and two smaller hind wings. Here, seen at 10 times magnification with the main veins and some the tiny wing hairs visible.
The rear wings are attached to the fore-wings by means of a series of minute hooks which grasp around the underside of the trailing edge of the fore-wings, making, in effect, one large wing surface. Here, seen at 60 times magnification.
Seen even closer, the hooks - called Hamuli - are obvious, as are the tiny hairs on the surface of the wings. Here, x200.
The wings beat up to 240 times per second but the bee cannot beat them at all until it's wing muscles reach 30 degrees C. It can do this even on cold days, by slipping it's wings 'out of gear' and vibrating the muscles independently of the wings, to warm them up, before re-engaging the wings and finally taking off. Brilliant!
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