Mimetic Polymorphism, a Controversial Chapter of Darwinism (Concluded)

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Abstract
-Fisher''s hypothesis of a model, and modifying genes is further discussed with reference to the time factor involved in the establishment of mimetic or polymorphic color patterns. Examples of Lepidopteran and gastropod patterns are offered to show that selection can work fast if new situations appear, and that no slow accumulation of modifiers is needed to produce the result which is reached completely, or almost completely by single mutational steps. In the parallel geographic variation of model and subspecies, the neo-Darwinian would have to assume that each subsp. of the model was first formed as a pre-adaptation to the new habitat by one or another genetic processes. The mimic, however, would be subjected to selection of modifiers which changed its pattern toward that of the new type model. Embryological development of Lepidopteran tail, wing, and antennal patterns is reviewed and where it is known, the genetics is correlated with it, to illustrate that single mutant genes can well produce similar differences of development where differential growth rates are involved. The conclusion is reached that Punnett''s interpretation of mimetic polymorphism by mutation (saltation) agrees with the facts better than Fisher''s neo-Darwinian theory.