BISTON BETULARIA:experiment

[Michael Gochfeld]

I haven't looked at the Kettlewell papers since graduate school. I think 
that the moths were placed on substrates from which predators could 
choose, and the results were consistent with the hypothesis that the 
dark moths were cryptically colored on sooty substrates, hence they 
COULD be favored by selection.  The experiment was used to test an 
hypothesis based on observations. The results were consistent with the 
hypothesis. I don't think anyone suggested that the Robins used in the 
experiment were actually the forces of natural selection.
	Whether there are other hypotheses with which the results might 
be equally consistent is another matter.  I don't think that such has 
been postulated.  However, I remember the experiments coming under 
attack for other methodologic reasons. Nonetheless, it was very 
influential work, with some very cooperative predators. 

M. Gochfeld