Postindustrial Melanism in the Peppered Moth

• DOI: 10.1126/science.231.4738.611
• Publication Date: 2006-10-05T20:28:52Z
• Authors: L. M. Cook; G. S. Mani; M. E. Varley
• Keywords: 0106 biological sciences; 01 natural sciences

New data show the geographical pattern of frequency of the melanic morph carbonaria of the peppered moth, Biston betularia , in 1983-84. These frequencies are compared with data from 1952 to 1970. After 20 years of smoke control, the area of high melanic frequency has contracted to the northeast. The change indicates a disadvantage to carbonaria of about 12 percent compared with 20 years ago. Computer simulations, which do not include the assumption of heterozygote advantage, provide a good match to the surface for the period 1952 to 1970, and also the 1983-84 surface. Experiments on visual predation have been criticized as giving unrepresentative estimates of selection but they permit satisfactory simulations to be made.