HONEY BEES 



recorded for twenty-four dances by fourteen workers over 

 a twenty-minute period, the angles recorded were as follows : 

 53 twice, 55 once, 6o° seventeen times, 65 ° once, 6j° once, 

 75 twice. 



There is finally the problem of what the bees do when 

 the sun is obscured by cloud. When the sky is completely 

 overcast, no dance is performed, and in the dark the tail- 

 wagging dance on a horizontal surface becomes completely 

 disorientated. If, however, a patch of blue sky is anywhere 

 visible, the tail-wagging dance is performed as usual, the 

 direction being indicated with reference to the true position 

 of the hidden sun. It has been suggested by von Frisch 

 that this could be explained if bees were sensitive to the plane 

 of polarisation of light, for it is known that the light reflected 

 by blue sky is partially polarised, and that the extent of 

 polarisation depends on the distance of the patch from the 

 true position of the sun. 



It should be explained that the light from the sun is emitted 

 in rays made up of waves vibrating in all planes, that is to 

 say unpolarised. But such light, when reflected from blue 

 sky, is more or less polarised, that is the light is orientated 

 so that the waves are all in one plane. Our own eyes are not 

 sensitive to the plane of polarisation of light, though motorists 

 know that a screen of " polaroid " which transmits polarised 

 light will cut down the glare of the light reflected from 

 puddles on the road or from snow. Von Frisch has very 

 recently found evidence that bees' eyes can respond to the 

 plane of polarisation of light, and that the direction of the 

 tail-wagging dance can be altered if a polaroid screen is 

 placed between the bees and the patch of blue sky which they 

 are using to detect the position of the sun. In fact, when the 

 polaroid is rotated through an angle the direction of the dance 

 is shifted through the same angle. 



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