Animals forming social groups that include breeders and nonbreeders present evolutionary paradoxes; why do breeders tolerate nonbreeders? And why do nonbreeders tolerate their situation? Both paradoxes are often explained with kin selection. Kin selection is, however, assumed to play little or no role in social group formation of marine organisms with dispersive larval phases. Yet, in some marine organisms, recent evidence suggests small‐scale patterns of relatedness, meaning that this assumption must always be tested. Here, we investigated the genetic relatedness of social groups of the emerald coral goby, Paragobiodon xanthosoma. We genotyped 73 individuals from 16 groups in Kimbe Bay, Papua New Guinea, at 20 microsatellite loci and estimated pairwise relatedness among all individuals. We found that estimated pairwise relatedness among individuals within groups was significantly higher than the pairwise relatedness among individuals from the same reef, and pairwise relatedness among individuals from the same reef was significantly higher than the pairwise relatedness among individuals from different reefs. This spatial signature suggests that there may be very limited dispersal in this species. The slightly positive relatedness within groups creates the potential for weak kin selection, which may help to resolve the paradox of why breeders tolerate subordinates in P. xanthosoma. The other paradox, why nonbreeders tolerate their situation, is better explained by alternative hypotheses such as territory inheritance, and ecological and social constraints. We show that even in marine animals with dispersive larval phases, kin selection needs to be considered to explain the evolution of complex social groups.

中文翻译：

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翡翠珊瑚虾虎鱼Paragobiodon xanthosoma的社会群体中的遗传相关性为弱亲属选择创造了潜力

形成包括育种者和非育种者在内的社会群体的动物呈现出进化悖论。为什么育种者会容忍非育种者？为什么非饲养者可以容忍他们的状况？经常用亲属选择来解释这两种悖论。然而，假定亲属选择在具有分散幼体阶段的海洋生物的社会群体形成中几乎没有或没有任何作用。但是，在一些海洋生物中，最近的证据表明相关性的小规模模式，这意味着必须始终检验这一假设。在这里，我们调查了翡翠珊瑚虾虎鱼Paragobiodon xanthosoma的社会群体的遗传相关性。我们对来自20个微卫星基因座的巴布亚新几内亚金贝湾的16个小组的73个个体进行了基因分型，并估计了所有个体之间的成对相关性。我们发现，组内个体之间的成对关联性显着高于来自同一礁石的个体之间的成对关联性，而来自同一礁石的个体之间的成对关联性显着高于来自不同礁石的个体之间的成对关联性。这种空间特征表明，该物种的扩散可能非常有限。群体之间的正相关性可能会导致亲属选择不力，这可能有助于解决为何育种者能够容忍黄原球菌下属的悖论。。另一个悖论，为什么非饲养者会容忍自己的处境，则可以通过替代假设（例如领土继承，生态和社会约束）更好地解释。我们表明，即使在具有分散幼体期的海洋动物中，也需要考虑亲属选择来解释复杂社会群体的演变。