Of Moths and Men by Judith Hooper, W. W. Norton, $26.95, ISBN 0393051218 Reviewed by Roy Herbert
EVOLUTION was still a contentious subject in the first half of the 20th century. It seemed doomed to remain a battleground. Whatever else its attractions and likelihood, the theory lacked proof and there never could be any because the process of natural selection would take scarcely imaginable stretches of time to be observed at work.
Revelation came in 1953. The 鈥減eppered鈥� moth, Biston betularia typica, with lightly speckled wings, had a melanic form, carbonaria, with black wings. The two distinct moths were awkward to explain. If natural selection led to the survival of the fittest, how could two thriving forms of the moth exist? There was a possible explanation. If it were true, then the theory of evolution would also be vindicated and, more, shown to be a far faster process than it inevitably seemed.
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The industrial cities of the north Midlands had been painting themselves with pollution for more than a hundred years. In one year, for instance, Manchester鈥檚 buildings and citizens suffered under a topcoat of 50 tonnes of soot per square mile. Might the carbonaria moth be an adaptation to this black rain? On a grimy background it would be hard for predators to see. Equally, the typica form would have the advantage in the countryside. Bernard Kettlewell, a physician and amateur lepidopterist seized on this idea of 鈥渋ndustrial melanism鈥� with raging enthusiasm, kept burning by his collaboration with E. B. Ford, an eminent Oxford geneticist. In 1953, after experiments in a wood near Birmingham, he found the evidence he needed. The news was a sensation, astonishing the scientific community and the public and delighting Darwinists. The melanic moth became a textbook example of evolution, solidly established. However, there have since been so many criticisms of Kettlewell鈥檚 work that industrial melanism has lost almost all credibility.
This is a fascinating story in itself, but it is also bedecked with the vicious quarrels of scientists, their political jockeying, childish sulks and cruelties, mostly euphemised as eccentricities. Hooper deals well with all of this eye-opening stuff, too. It is a pity that she is prone to wander off on irrelevancies. One of the characters was a prisoner of war in Stalag Luft III, so she tells the story of the Great Escape. Ignore the irritation. This is a marvellous tale.