Data from: Sex-dependent expression of behavioural genetic architectures and the evolution of sexual dimorphism

Empirical studies imply that sex-specific genetic architectures can resolve evolutionary conflicts between males and females, and thereby facilitate the evolution of sexual dimorphism. Sex-specificity of behavioural genetic architectures have, however, rarely been considered. Moreover, as the expression of genetic (co)variances is often environment-dependent, general inferences on sex-specific genetic architectures require estimates of quantitative genetics parameters under multiple conditions. We measured exploration and aggression in pedigreed populations of southern field crickets (Gryllus bimaculatus) raised on either naturally balanced (free-choice) or imbalanced (protein-deprived) diets. For each dietary condition, we measured for each behavioural trait (i) level of sexual dimorphism, (ii) level of sex-specificity of survival selection gradients, (iii) level of sex-specificity of additive genetic variance, and (iv) strength of the cross-sex genetic correlation. We report here evidence for sexual dimorphism in behaviour as well as sex-specificity in the expression of genetic (co)variances as predicted by theory. The additive genetic variances of exploration and aggression were significantly greater in males compared to females. Cross-sex genetic correlations were highly positive for exploration but deviating (significantly) from one for aggression; findings were consistent across dietary treatments. This suggests that genetic architectures characterize the sexually dimorphic focal behaviours across various key environmental conditions in the wild. Our finding also highlights that sexual conflict can be resolved by evolving sexually independent genetic architectures.

实证研究表明，性别特异性遗传架构（sex-specific genetic architectures）能够解决雌雄个体间的进化冲突，进而促进性二态性（sexual dimorphism）的演化。然而，行为遗传架构（behavioural genetic architectures）的性别特异性却极少被纳入研究考量。此外，由于遗传（共）方差（genetic (co)variances）的表达往往依赖于环境，因此要对性别特异性遗传架构做出一般性推论，需要在多种环境条件下对数量遗传学（quantitative genetics）参数进行估算。
本研究对饲养于天然平衡日粮（自由取食（free-choice））或失衡日粮（蛋白质剥夺（protein-deprived））环境下的双斑蟋蟀（Gryllus bimaculatus）谱系种群的探索行为与攻击行为进行了测定。针对每种日粮条件，我们针对每个行为性状（behavioural trait）测定了四项指标：(i) 性二态性水平；(ii) 存活选择梯度（survival selection gradients）的性别特异性水平；(iii) 加性遗传方差（additive genetic variance）的性别特异性水平；(iv) 跨性别遗传相关（cross-sex genetic correlation）强度。
本研究在此报告了行为层面存在性二态性，以及遗传（共）方差的表达存在性别特异性的实证证据，这与理论预测相符。雄性的探索行为与攻击行为的加性遗传方差显著高于雌性。探索行为的跨性别遗传相关系数呈高度正相关，但攻击行为的该系数则显著偏离1；上述发现在不同日粮处理组中均保持一致。
这表明，在野外多种关键环境条件下，遗传架构均可对性二态性目标行为进行表征。本研究结果同时表明，通过演化出性别独立的遗传架构，可解决雌雄个体间的进化冲突。