Data from: Highly asymmetric fine-scale genetic structure between sexes of African striped mice and indication for condition dependent alternative male dispersal tactics

Sex-biased dispersal is observed in many taxa, but few studies have compared sex-biased dispersal among and within populations. We addressed the magnitude and habitat dependency of sex-biased dispersal in social African striped mice by separating group-related from population-related genetic variance to understand the contribution of each sex to deme structure. As dispersal over unoccupied habitat is likely to be more costly than dispersal within a population, we predicted that individuals leaving the natal population have a lower body condition, being inferior to heavier territorial individuals. Fine-scale genetic structure was detected in both sexes. Female relatedness decreased continuously from R = 0.21 at 25 m to zero at 500 m. Maximum male relatedness R = 0.05 was constant at distances between 25 and 75 m, becoming zero at 100 m. Genetic variance (FST) among seven locations was significantly higher in females than in males, while inbreeding estimates (FIS) were significantly higher in males than in females. Assignment tests estimated significantly more migrants among males, while Bayesian clustering estimated only a single genetic unit cluster for males among the seven locations. The mean body mass of migrant males (44 g) was significantly lower than for males that remained resident and thus dispersed within their sub-population (48 g). Combined, the results showed habitat-independent male-biased dispersal and high female philopatry, and suggested that body condition was more important than kinship in male dispersal decisions. We suggest that locally inferior males are important for gene flow between sub-populations. Thus, males might follow alternative dispersal tactics.

性别偏倚扩散（sex-biased dispersal）在诸多生物类群中均有观测记录，但目前鲜有研究对种群间及种群内的性别偏倚扩散模式开展对比分析。本研究以群居非洲条纹鼠为研究对象，通过分离群体相关与种群相关的遗传方差，解析不同性别对居群（deme）结构的贡献，以此探讨该物种性别偏倚扩散的程度及其生境依赖性。由于在未占据生境中的扩散成本高于种群内部扩散，我们推测离开出生种群的个体身体状况较差，弱于体重更大的领域性个体。两性均检测到精细尺度遗传结构：雌性亲缘系数（relatedness）从25米处的0.21持续下降，至500米时降至0；雄性亲缘系数最大值为0.05，在25至75米区间内保持稳定，至100米时降至0。七个采样点间的遗传方差（FST，种群分化系数）在雌性群体中显著高于雄性，而近交系数（FIS）则在雄性群体中显著高于雌性。个体归属检验（assignment tests）结果显示雄性的迁移个体数量显著更多，而贝叶斯聚类（Bayesian clustering）分析表明，七个采样点的雄性仅构成一个遗传单元集群。扩散雄性的平均体重（44克）显著低于留在亚种群内完成扩散的定居雄性（48克）。综合来看，研究结果揭示了生境非依赖性的雄性偏倚扩散模式与雌性的高恋巢性（philopatry），同时提示在雄性扩散决策中，身体状况较亲缘关系更为关键。我们提出，本地体型较弱的雄性对亚种群间的基因流动具有重要意义。据此，雄性可能采取了多样化的扩散策略。