Theoretical Biology Group, University of Groningen, Groningen, The Netherlands.
Biol Lett. 2012 Aug 23;8(4):533-6. doi: 10.1098/rsbl.2012.0159. Epub 2012 Apr 11.
With an increasing amount of data becoming available, comparative analyses have called attention to the associations between cooperative breeding, monogamy and relatedness. We focus here upon the association between allomaternal care and relatedness among females within a social unit. Previous studies found a positive association, but such results date back to before molecular tools were in common use, they considered only a few mammalian orders, neglected phylogenetic clustering and/or did not correct for group sizes. Here, we use molecular data on relatedness from 44 species of mammals to investigate the phylogenetic clustering of, and the association between, allomaternal care and relatedness among females within a social unit. We find (i) a strong phylogenetic signal for allomaternal care and a moderate one for relatedness and group size, and (ii) a positive association between relatedness and allomaternal care, even when correcting for the smaller than average group sizes in species with allomaternal care. We also find that, in species without allomaternal care, adult females often live with unrelated females even when groups are small. We discuss these results in the light of recent evidence for the role of kin selection and the monogamy hypothesis in cooperative breeding.
随着越来越多的数据可用，比较分析引起了人们对合作繁殖、一夫一妻制和亲缘关系之间关联的关注。我们在这里关注的是社会单位内雌性个体之间的异亲抚育和亲缘关系之间的关联。先前的研究发现了正相关，但这些结果可以追溯到分子工具尚未广泛使用的时候，它们只考虑了少数几个哺乳动物目，忽视了系统发育聚类，或者没有对群体大小进行校正。在这里，我们使用来自 44 种哺乳动物的亲缘关系的分子数据来研究异亲抚育的系统发育聚类，以及社会单位内雌性个体之间的亲缘关系和异亲抚育之间的关系。我们发现(i) 异亲抚育存在强烈的系统发育信号，而亲缘关系和群体大小存在中等程度的系统发育信号，以及 (ii) 即使在对具有异亲抚育的物种的平均群体大小较小进行校正后，亲缘关系与异亲抚育之间也存在正相关。我们还发现，在没有异亲抚育的物种中，即使群体较小，成年雌性也经常与不相关的雌性生活在一起。我们根据最近关于亲缘选择和一夫一妻制假说在合作繁殖中的作用的证据来讨论这些结果。
