The Evolution of Sex with Exposure to Maternally Transmitted Parasites

<p>Darkly shaded regions indicate parameter values under which increased sex evolved in simulations. Lightly shaded regions indicate parameter values that selected against sex. A detailed description of the simulations is presented in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040265#sd003" target="_blank">Protocol S3</a>. The effect of the modifier was assumed to be additive, i.e., <i>h_σ</i> = ½. Left: two-locus IMA model with <i>d_R</i> = 0.25. Right: two-locus Gene-For-Gene (GFG) model with a cost of resistance alleles of <i>c</i> = 0.05 <i>v</i> and cost of infectious alleles of <i>k</i> = 0.3. Resistance alleles were assumed to be completely dominant. MA model results were very similar to IMA model results (unpublished data). For the IMA model, the parameter combination with <i>σ</i> = 0.5, <i>v</i> = 0.2, <i>λ</i> = 1, and <i>ϕ</i> = 0.1, increased sex evolved in 90% of replicates; increased sex evolved in 95% of replicates the parameter combination with <i>σ</i> = 0.1, <i>v</i> = 0.8, <i>λ</i> = 10, and <i>ϕ</i> = 0.05; for other parameter combinations, sex evolved in all replicates in the direction indicated by shading. </p