Figure 1.

Expected genotypes of hybrids and backcrosses assuming either sex linkage or autosomal inheritance. The large Z and W represent the sex chromosomes, A the autosomal chromosomes, whereas in the superscript Z and E represent alleles from respective the pheromone strain. patBC paternal backcrosses (crossing each of the hybrid females with either E-strain (ZExE, EZxE) or Z-strain males (ZExZ, EZxZ)). Note that in Lepidoptera females are the heterogametic sex. This means that paternal crosses, i.e., a female hybrid crosses with a male pure strain, in the case of a sex-linked factor will result in single phenotype offspring only with respect to that factor (either Z, hybrid, or E phenotypes).