Fig. 1.

Example of numerical projections for allele frequencies (A and B), the covariance between the T₂ (attractive male display) and R₂ (female resistance) alleles, D_TR (C and D), and the proportion of matings that are with T₂ males for non-resistant (R₁) females, resistant (R₂) females, and for matings overall (E and F), for the cases of no female resistance to forced fertilization (left panels A, C, E) and fully effective female resistance (right panels B, D, F). In both cases, initial allele frequencies are T₂=0.5, P₂=0.5, R₂=0.05, and C₂=0.05; s_t=s_c=0.1, b=0.29, and a=23. The frequency of the allele for male attractiveness (t₂; the black dotted line in A and B) remains constant because of our assumption of maintained diversity at the T locus. Note that the number of generations to equilibrium is different for the two cases. Proportion of matings with T₂ males was calculated each generation before recombination and mutation. The upper and lower black dotted boundary lines in panels E and F represent the equilibrium proportion of matings with T₂ males for the system with free mate choice (a projection with no coercion) and restricted mate choice (a projection with coercion and no resistance), respectively. The three lines in E overlap because females do not differ in their ability to resist coercion. See Figure S3 for graphs of the remaining two-way linkages not shown here.