Data from: Promiscuity resolves constraints on social mate choice imposed by population viscosity

Population viscosity can have major consequences for adaptive evolution, in particular for phenotypes involved in social interactions. For example, population viscosity increases the probability of mating with close kin, resulting in selection for mechanisms that circumvent the potential negative consequences of inbreeding. Female promiscuity is often suggested to be one such mechanism. However, whether avoidance of genetically similar partners is a major selective force shaping patterns of promiscuity remains poorly supported by empirical data. Here, we show (i) that fine-scale genetic structure constrains social mate choice in a pair-bonding lizard, resulting in individuals pairing with genetically similar individuals, (ii) that these constraints are circumvented by multiple mating with less related individuals and (iii) that this results in increased heterozygosity of offspring. Despite this, we did not detect any significant effects of heterozygosity on offspring or adult fitness or a strong relationship between pair relatedness and female multiple mating. We discuss these results within the context of incorporating the genetic context dependence of mating strategies into a holistic understanding of mating system evolution.

种群粘性（population viscosity）对适应性进化（adaptive evolution）具有显著影响，尤其作用于参与社会互动的表型（phenotypes）。例如，种群粘性会提升与近亲（close kin）交配的概率，进而推动演化出规避近交（inbreeding）潜在负面影响的相关机制。雌性混交（female promiscuity）常被视为这类机制之一。然而，规避遗传相似性配偶是否为塑造混交模式的主要选择压力（selective force），目前仍未得到实证数据的充分支持。本研究证实：其一，精细尺度遗传结构（fine-scale genetic structure）限制了结对配偶型蜥蜴（pair-bonding lizard）的社会配偶选择（social mate choice），使得个体倾向于与遗传相似的个体配对；其二，这类限制可通过与遗传相关性更低的个体进行多次交配（multiple mating）得以规避；其三，该行为能够提升后代的杂合度（heterozygosity）。尽管如此，本研究未检测到杂合度对子代或成体适合度（fitness）存在显著影响，亦未发现配对个体的遗传相关性与雌性多次交配之间存在强关联。我们将研究结果置于如下框架展开讨论：将交配策略（mating strategies）的遗传背景依赖性纳入交配系统进化（mating system evolution）的整体性认知当中。