The peppered moth and industrial melanism


The peppered moth and industrial melanism: evolution of an icon

Speaker: Dr Laurence M Cook

peppered moth

Since their first discovery multiple causes have been suggested for changes in melanic frequency in the peppered moth Biston betularia and other industrial melanic moths. These have included higher intrinsic fitness of melanic forms and selective predation for camouflage. The possible existence and origin of heterozygote advantage has been proposed and debated. As a result of experiment, selective predation became the favoured explanation and is undoubtedly the major factor driving the frequency change. Declining melanic frequencies since the 1970s have been monitored and indicate appreciable visual selection together with higher migration rates than direct estimates suggest or else, or in addition, non-visual selection. Molecular genetics shows the melanic (carbonaria) allele to be related to a butterfly wing patterning locus and to have a single origin in Britain. These themes will be outlined and discussed.

This lecture is free and open to all. Registration is not necessary.