Dugdale Hannah L, Macdonald David W, Pope Lisa C, Burke Terry
Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Tubney House, Abingdon Road, Tubney OX13 5QL, UK.
Mol Ecol. 2007 Dec;16(24):5294-306. doi: 10.1111/j.1365-294X.2007.03571.x. Epub 2007 Oct 30.
The costs and benefits of natal philopatry are central to the formation and maintenance of social groups. Badger groups, thought to form passively according to the resource dispersion hypothesis (RDH), are maintained through natal philopatry and delayed dispersal; however, there is minimal evidence for the functional benefits of such grouping. We assigned parentage to 630 badger cubs from a high-density population in Wytham Woods, Oxford, born between 1988 and 2005. Our methodological approach was different to previous studies; we used 22 microsatellite loci to assign parent pairs, which in combination with sibship inference provided a high parentage assignment rate. We assigned both parents to 331 cubs at > or = 95% confidence, revealing a polygynandrous mating system with up to five mothers and five fathers within a social group. We estimated that only 27% of adult males and 31% of adult females bred each year, suggesting a cost to group living for both sexes. Any strong motivation or selection to disperse, however, may be reduced because just under half of the paternities were gained by extra-group males, mainly from neighbouring groups, with males displaying a mixture of paternity strategies. We provide the strongest evidence to date for multiple-paternity litters, and for the first time show that within-group and extra-group males can sire cubs in the same litter. We investigate the factors that may play a role in determining the degree of delayed dispersal and conclude that the ecological constraints hypothesis, benefits of philopatry hypothesis, and life history hypothesis may all play a part, as proposed by the broad constraints hypothesis.
出生地留居的成本与收益是社会群体形成与维持的核心要素。獾群被认为是根据资源分散假说（RDH）被动形成的，通过出生地留居和延迟扩散得以维持；然而，关于这种群体形成的功能益处的证据却极少。我们为来自牛津郡怀瑟姆森林高密度种群、在1988年至2005年出生的630只獾幼崽确定了亲子关系。我们的方法与以往研究不同；我们使用22个微卫星位点来确定亲代配对，这与同胞关系推断相结合，提供了较高的亲子关系确定率。我们以大于或等于95%的置信度为331只幼崽确定了双亲，揭示了一种多配制的交配系统，一个社会群体中最多有五个母亲和五个父亲。我们估计每年只有27%的成年雄性和31%的成年雌性进行繁殖，这表明群居对两性来说都有成本。然而，任何强烈的扩散动机或选择可能都会降低，因为略低于一半的父权是由群体外雄性获得的，主要来自相邻群体，雄性表现出多种父权策略。我们提供了迄今为止关于多父本窝仔的最有力证据，并且首次表明群体内和群体外雄性可以使同一窝中的幼崽受孕。我们研究了可能在决定延迟扩散程度方面起作用的因素，并得出结论，生态限制假说、留居益处假说和生活史假说可能都如广义限制假说所提出的那样发挥了作用。
