Social selection and indirect genetic effects (IGEs) are established concepts in both behavioural ecology and evolutionary genetics. While IGEs describe effects of an individual’s genotype on phenotypes of social partners (and may thus affect their fitness indirectly), the concept of social selection assumes that a given phenotype in one individual affects the fitness of other individuals directly. Although different frameworks, both have been used to investigate the evolution of social traits, such as cooperative behaviour. Despite their similarities (both concepts consider interactions among individuals), they differ in the type of interaction. It remains unclear whether the two concepts make the same predictions about evolutionary trajectories or not. To address this question, we investigate four possible scenarios of social interactions and compare the effects of IGEs and social selection for trait evolution in a multi-trait multi-member model. We show that the two mechanisms can yield similar evolutionary outcomes and that both can create selection pressure at the group level. However, the effect of IGEs can be stronger due to the possibility of feedback loops. Finally, we demonstrate that IGEs, but not social selection gradients, may lead to differences in the direction of evolutionary response between genotypes and phenotypes.

中文翻译：

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结构性人群中的社会选择和间接遗传效应。

社会选择和间接遗传效应 (IGE) 是行为生态学和进化遗传学中的既定概念。虽然 IGE 描述了个体基因型对社会伙伴表型的影响（因此可能间接影响他们的适应度），但社会选择的概念假设一个人的给定表型直接影响其他个体的适应度。尽管框架不同，但两者都被用于研究社会特征的演变，例如合作行为。尽管它们有相似之处（这两个概念都考虑了个体之间的交互），但它们在交互类型上有所不同。目前尚不清楚这两个概念是否对进化轨迹做出了相同的预测。为了回答这个问题，我们研究了社会互动的四种可能场景，并在多特征多成员模型中比较了 IGE 和社会选择对特征进化的影响。我们表明这两种机制可以产生相似的进化结果，并且都可以在群体层面产生选择压力。然而，由于反馈回路的可能性，IGE 的影响可能会更强。最后，我们证明了 IGEs，而不是社会选择梯度，可能导致基因型和表型之间进化反应方向的差异。由于反馈回路的可能性，IGE 的效果可能更强。最后，我们证明了 IGEs，而不是社会选择梯度，可能导致基因型和表型之间进化反应方向的差异。由于反馈回路的可能性，IGE 的效果可能更强。最后，我们证明了 IGEs，而不是社会选择梯度，可能导致基因型和表型之间进化反应方向的差异。