Evidence for a link between local and seasonal cycles in gene frequencies and latitudinal gene clines in a cyclic parthenogen

In an earlier study (Rhombergh et al., Can. J. Genet. Cytol. 27: 224–232, 1985) of natural populations of the cyclic parthenogenetic Rose aphids, Macrosiphum rosae, 6 out of 31 loci were found to be polymorphic and one locus (Esterase-4) showed cyclic seasonal changes in gene and genotypic frequencies. Assuming that the Est-4 polymorphism was balanced and due to some climatic factor that varies seasonally, and realizing that most environmental …