Non-random mating in wild populations of polymorphic adalia bipunctata

Abstract

The nature of the factors maintaining the colour polymorphism in Adalia bipunctata has been the subject of much discussion and in some populations a tendency for the melanic morphs to mate more frequently than the non- melanics has been reported. The morph frequencies among mating pairs in wild populations of A. bipunctata in England have been scored and analysed in order to discover whether mating between morphs is a random process. Data from the literature are also analysed in the same way and the methods of analysis adopted by earlier workers are discussed. It is concluded that mating between morphs is frequency dependent so that it is the rare morph in the population, regardless of colour, which mates more frequently. This appears to be a further method by which the polymorphism in this species is maintained. © 1979 The Genetical Society of Great Britain.