Natural Selection and the Maintenance of Colour Pattern Polymorphism in the Australian Plague Locust Chortoicetes terminifera

Abstract

Twelve samples of C. termini/era from seven locations in eastern Australia were analysed for colour pattern polymorphism. Although there was heterogeneity between the samples the overall frequencies of the colour pattern genotypes were very similar. Males and females showed consistent differences in their genotype frequencies and this is presumed to reflect differential selection between the two sexes. A comparison between observed genotype frequencies and those expected under random mating and in the absence of selection revealed large differences. In particular, genotypes heterozygous for two dominant genes were consistently underrepresented. While these differences could result from non-random mating it is argued that they are more likely to be due to viability differences between the genotypes.