Within-group relatedness is correlated with colony-level social structure and reproductive sharing in a social fish.

In group-living species, the degree of relatedness among group members often governs the extent of reproductive sharing, cooperation and conflict within a group. Kinship among group members can be shaped by the presence and location of neighbouring groups, as these provide dispersal or mating opportunities that can dilute kinship among current group members. Here, we assessed how within-group relatedness varies with the density and position of neighbouring social groups in Neolamprologus pulcher, a colonial and group-living cichlid fish. We used restriction site-associated DNA sequencing (RADseq) methods to generate thousands of polymorphic SNPs. Relative to microsatellite data, RADseq data provided much tighter confidence intervals around our relatedness estimates. These data allowed us to document novel patterns of relatedness in relation to colony-level social structure. First, the density of neighbouring groups was negatively correlated with relatedness between subordinates and domi...在群居物种中，群体成员间的亲缘关系程度往往决定了群体内繁殖共享、合作与冲突的规模。群体成员的亲缘关系会受到邻近群体的存在与空间分布的影响：邻近群体可为个体提供扩散或交配机会，进而削弱当前群体内成员的亲缘关系水平。本研究以布氏新亮丽鲷（Neolamprologus pulcher）——一种兼具集群性与群居性的慈鲷鱼类——为研究对象，探讨了群体内亲缘关系如何随邻近社会群体的密度与空间位置发生变化。我们采用限制性酶切位点相关DNA测序（RADseq）技术，生成了数千个多态性单核苷酸多态性（Single Nucleotide Polymorphism, SNPs）位点。相较于微卫星（microsatellite）数据，RADseq数据为我们的亲缘关系估计值提供了精度更高的置信区间。依托该测序数据，我们得以揭示与集群社会结构相关的全新亲缘关系模式。其一，邻近群体的密度与从属个体和优势个体间的亲缘关系呈负相关……