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.

替代性繁殖策略（alternative reproductive tactics）指同一性别个体通过不同策略成功获取交配机会的现象，此类策略通常与条件性同性二态性（conditional intrasexual dimorphisms）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，若不同表型在遗传上相互解耦且可自由进化至各自的表型最适值，则更易产生同性二态性。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策略冲突（intralocus tactical conflict）。
本研究针对球螨（Rhizoglyphus echinopus）与欧洲球螋（Forficula auricularia）的雄性二态性遗传架构展开探究。我们采用半同胞育种设计，评估了两个物种中二态性与单态性性状的遗传力以及性内、性间遗传相关。
研究发现了两种截然不同的模式：欧洲球螋的二态性性状表现出较低的同性遗传相关，提示其基因座内策略冲突正逐步得到解决；而球螨的多数性状则呈现出较高且显著的同性遗传相关，表明球螨的雄性形态在进化至表型最适值的过程中可能受到限制。
这一结果同时表明，即便存在强烈的遗传约束，同性二态性仍可进化，这与当前的理论预测相悖。
我们讨论了该遗传约束的研究意义，并强调了基因座内策略冲突对于理解同性二态性的潜在重要性。