Melanism And The Study Of Evolution

The significance of industrial melanism in the Lepidoptera to evolutionary biology has been considerable. It has provided one of the best observed examples of evolutionary change caused by natural selection and has shown that Darwinian selection can be a strong force. In the peppered moth, differential bird predation, together with migration, has been primarily responsible for the rise and fall of the melanic form carbonaria.

Although the story of the peppered moth is undoubtedly more complex than usually related, data accumulated during the past 40 years have done nothing to undermine Tutt's initial hypothesis of the role of differential bird predation or Kettlewell's experimental demonstrations of this role.

Within the Lepidoptera, the factors responsible for melanism and the forms of melanism that result are very variable. Because a great variety of factors may promote melanism, it may be misleading to extrapolate from one population to another, let alone from one species to another. Even within one class of melanism, the relative influence of different aspects of a species' biology will vary between species. Each species that has evolved melanic forms will have done so in the presence of a variety of different intrinsic and extrinsic circumstances. The differences in the factors affecting melanism in even the few well-studied cases suggest that there is still enormous scope for original research into this phenomenon. However, in species in which melanism is strongly correlated with pollution levels, such as the peppered moth, we are rapidly running out of time to pursue research into this phenomenon as melanics decline.

See Also the Following Articles

Coloration • Crypsis • Genetic Variation • Lepidoptera • Pollution • Thermoregulation

Further Reading

Cook, L. M. (2000). Changing view on melanic moths. Biol. J. Linn. Soc. 69, 431-441.

Grant, B. S., Owen, D. F., and Clarke, C. A. (1995). Decline of melanic moths. Nature 373, 565. Grant, B. S., Owen, D. F., and Clarke, C. A. (1996). Parallel rise and fall of melanic peppered moths in America and Britain. J. Hered. 87, 351-357. Haldane, J. B. S. (1924). A mathematical theory of natural and artificial selection. Trans. Cambridge Philos. Soc. 23, 19-41. Howlett, R. J., and Majerus, M. E. N. (1987). The understanding of industrial melanism in the peppered moth (Biston betularia) (Lepidoptera: Geometridae). Biol. J. Linn. Soc. 30, 31-44. Kettlewell, H. B. D. (1955). Selection experiments on industrial melanism in the Lepidoptera. Heredity 9, 323-342.

Kettlewell, H. B. D. (1956). Further selection experiments on industrial melanism in the Lepidoptera. Heredity 10, 287—301.

Kettlewell, H. B. D. (1973). "The Evolution of Melanism." Clarendon Press, Oxford.

Majerus, M. E. N. (1998). "Melanism: Evolution in Action." Oxford University Press, Oxford.

Majerus, M. E. N., Brunton, C. F. A., and Stalker, J. (2000). A bird's eye view of the peppered moth. J. Evol. Biol 13, 155—159.

Owen, D. F. (1961). Industrial melanism in North American moths. Am. Nat. 95, 227-233.

Tutt, J. W. (1896). "British Moths." George Routledge, London.

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