Do bees distinguish colours?
ADRIAN HORRIDGE delves into the enlightening research world of bee vision.
Humans have long believed that the colours of flowers have evolved to attract bees.
But my recent experiments show that bees actually distinguish shapes and patterns by basing their decisions on seeing the colour green and shades of blue.
Back in 1912, Carl von Hess, professor of ophthalmology at the University of Münich, Germany, concluded in his book on the physiology of animal vision bees do not distinguish between colours in the way humans enjoy. His sources were few but reliable.
Karl von Frisch, a young assistant in zoology at the same university, set to work to demonstrate that bees distinguish flower shapes and colours from all shades of grey, which is a test of defects in human colour vision.
In 1914, von Frisch demonstrated his trained bees at a large scientific congress in Freiburg.
However, he ignored some experiments that failed.
The bees had learned nothing when trained to go to mid-grey or green versus a palette of all shades of grey.
In response, von Hess showed bees learned when rewarded on blue squares on a blue and yellow checkerboard but they learned nothing (except to avoid blue) when rewarded on yellow squares.
Neither repeated the experiments of the other; neither understood their own data.
Von Hess died in 1923. Von Frisch won by default, became a dominant force in German zoology and later shared a Nobel Prize for his work on bees.
And that's where I come in.