PNAS:猴母亲或影响儿子的生育

2011-11-09 admin EurekAlret
浏览

一项研究提出,在某些平等主义的灵长类种群中的母亲可能促进他们的儿子的生殖成功。

 

Karen Strier及其同事调查了生活在巴西Minas Gerais的受保护森林Reserva Particular do Patrim?nio Natural Feliciano Miguel Abdala保护区的绒毛蛛猴的父亲血缘。

这种濒危的灵长类动物并不形成等级制,而且是生活在一个平等主义的社会中,雄性留在出生地,形成和平的同胞关系,而雌性倾向于迁移到其他群体中。

对从67只猴子那里收集的粪材料的DNA分析确定了22只幼猴有13个不同的父亲,这些父亲及其雌性配偶都没有密切的亲缘关系。后代最多的雄性只是18%的幼猴的父亲。

这组作者说这些发现与生活在等级制中的灵长类动物形成了鲜明的对比,诸如山地大猩猩和黑猩猩,后者个体最多的后代占总数的30%到85%之间。

绒毛蛛猴的雄性在性成熟行为和首次生殖的年龄之间还有相对较长的大约2年的延迟。

由于雄性终生与雄性亲属及其母亲生活在一起,这组科研人员提出,这个物种的母亲可能让她们的儿子更多地与可能无亲缘关系的雌性伴侣接触,增加了她们的儿子找到伴侣的几率,同时还可能增加了孙辈的数量。

 

Low paternity skew and the influence of maternal kin in an egalitarian, patrilocal primate

Karen B. Strier, Paulo B. Chaves, Sérgio L. Mendes, Valéria Fagundes, and Anthony Di Fiore

Levels of reproductive skew vary in wild primates living in multimale groups depending on the degree to which high-ranking males monopolize access to females. Still, the factors affecting paternity in egalitarian societies remain unexplored. We combine unique behavioral, life history, and genetic data to evaluate the distribution of paternity in the northern muriqui (Brachyteles hypoxanthus), a species known for its affiliative, nonhierarchical relationships. We genotyped 67 individuals (22 infants born over a 3-y period, their 21 mothers, and all 24 possible sires) at 17 microsatellite marker loci and assigned paternity to all infants. None of the 13 fathers were close maternal relatives of females with which they sired infants, and the most successful male sired a much lower percentage of infants (18%) than reported for the most successful males in other species. Our findings of inbreeding avoidance and low male reproductive skew are consistent with the muriqui's observed social and sexual behavior, but the long delay (≥2.08 y) between the onset of male sexual behavior and the age at which males first sire young is unexpected. The allocation of paternity implicates individual male life histories and access to maternal kin as key factors influencing variation in paternal—and grandmaternal—fitness. The apparent importance of lifelong maternal investment in coresident sons resonates with other recent examinations of maternal influences on offspring reproduction. This importance also extends the implications of the “grandmother hypothesis” in human evolution to include the possible influence of mothers and other maternal kin on male reproductive success in patrilocal societies.