Recognition of Appropriate Backgrounds by the Pale and Black Phases of Lepidoptera

Abstract

THE Lepidoptera, with their frequent examples of highly specialized cryptic coloration, have been used extensively for experiments on the various aspects of evolution. More marked evolutionary adjustments have in fact been witnessed in these than in any other natural order. Thus J. B. S. Haldane¹ showed that in the Manchester district between the years 1848 and 1898, the jet-black form of the peppered moth (Biston betularia f. carbonaria) had an approximate 30 per cent advantage over pale lichen-like individuals, which were the only ones known there until the middle of the last century. Nor is this occurrence unique among the Lepidoptera of Britain. About fifty other species are, at the present time, in the process of changing their populations from light individuals to black in large areas of England.