Bradley Brenda J, Doran-Sheehy Diane M, Vigilant Linda
Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK.
Proc Biol Sci. 2007 Sep 7;274(1622):2179-85. doi: 10.1098/rspb.2007.0407.
Female philopatry and male dispersal are the norm for most mammals, and females that remain in their natal region often derive foraging or social benefits from proximity to female kin. However, other factors, such as constraints on group size or a shortage of potential mates, may promote female dispersal even when female kin associations would be beneficial. In these cases, female kin associations might develop, not through female philopatry, but through female emigration to the same group. To date, little attention has been focused on the potential for kin-biased behaviour between females in female-dispersing species. Here we investigate the genetic relationships among adults in eight wild groups of unhabituated western gorillas (Gorilla gorilla) at the Mondika Research Center using microsatellite genotyping of DNA collected from hair and faeces. We found that almost half (40%) of adult females had an adult female relative in the same group and average within-group relatedness among females was significantly higher than that expected under a model of random dispersal. This provides the first genetic evidence that females can maintain social associations with female relatives in spite of routine natal and secondary dispersal. In addition, we show that females appear to avoid related silverback males when making dispersal decisions, suggesting that a strategy of non-random female dispersal may also function to avoid inbreeding.
雌性留居和雄性扩散是大多数哺乳动物的常态，留在出生区域的雌性通常会因与雌性亲属 proximity 而获得觅食或社交方面的好处。然而，其他因素，如群体规模的限制或潜在配偶的短缺，即使雌性亲属关系有益，也可能促使雌性扩散。在这些情况下，雌性亲属关系可能不是通过雌性留居形成，而是通过雌性迁移到同一群体形成。迄今为止，很少有研究关注雌性扩散物种中雌性之间亲属偏向行为的可能性。在这里，我们使用从毛发和粪便中收集的 DNA 进行微卫星基因分型，调查了蒙迪卡研究中心八个未习惯化西部大猩猩（Gorilla gorilla）野生群体中成年个体之间的遗传关系。我们发现，几乎一半（40%）的成年雌性在同一群体中有成年雌性亲属，雌性之间的群体内平均亲缘关系显著高于随机扩散模型下预期的水平。这提供了首个遗传证据，表明尽管有常规的出生和二次扩散，雌性仍能与雌性亲属维持社会联系。此外，我们表明，雌性在做出扩散决定时似乎会避开有亲缘关系的银背雄性，这表明非随机雌性扩散策略也可能起到避免近亲繁殖的作用。
