Data from: Mixed evidence for the erosion of inter-tactical genetic correlations through intralocus tactical conflict

Alternative reproductive tactics, whereby members of the same sex use different tactics to secure matings are often associated with conditional intrasexual dimorphisms. Given the different selective pressures on males adopting each mating tactic,, intrasexual dimorphism is more likely to arise if phenotypes are genetically uncoupled and free to evolve towards their phenotypic optima. However, in this context, genetic correlations between male morphs could result in intralocus tactical conflict. We investigated the genetic architecture of male dimorphism in bulb mites (Rhizoglyphus echinopus) and earwigs (Forficula auricularia). We used half-sibling breeding designs to assess the heritability and intra/intersexual genetic correlations of dimorphic and monomorphic traits in each species. We found two contrasting patterns; F. auricularia exhibited low intrasexual genetic correlations for the dimorphic trait, suggesting that the intralocus tactical conflict is moving towards a resolution. Meanwhile, R. echinopus exhibited high and significant intrasexual genetic correlations for most traits, suggesting that morphs in the bulb mite may be limited in evolving to their optima. This also shows that intrasexual dimorphisms can evolve despite strong genetic constraints, contrary to current predictions. We discuss the implications of this genetic constraint and emphasize the potential importance of intralocus tactical conflict for our understanding of intrasexual dimorphisms.同性个体采用不同策略以获得交配机会的替代性繁殖策略，通常与条件性性内二态性相关联。鉴于采用不同交配策略的雄性面临各异的选择压力，若表型在遗传上相互解耦且可自由向其最优表型演化，则性内二态性更易出现。然而在此情境下，雄性形态间的遗传相关可能引发基因座内战术冲突（intralocus tactical conflict）。我们以根螨（Rhizoglyphus echinopus）与蠼螋（Forficula auricularia）为研究对象，探究其雄性二态性的遗传架构。我们采用半同胞繁育设计，评估了两个物种中二态与单态性状的遗传力以及性别内和跨性别的遗传相关。研究发现了两种截然不同的模式：蠼螋的二态性状在性别内呈现较低的遗传相关，这表明基因座内战术冲突正逐步得到解决。与此同时，根螨的多数性状均表现出较高且显著的性别内遗传相关，这意味着根螨的形态类群在向最优表型演化的过程中可能受到限制。该结果同时表明，即便存在强烈的遗传约束，性内二态性仍可演化，这与当前的理论预测相悖。我们讨论了上述遗传约束的研究意义，并强调了基因座内战术冲突对于理解性内二态性的潜在重要性。