Badyaev A V, Oh K P, Mui R
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721-0088, USA.
J Evol Biol. 2006 May;19(3):909-21. doi: 10.1111/j.1420-9101.2005.01041.x.
In species that produce broods of multiple offspring, parents need to partition resources among simultaneously growing neonates that often differ in growth requirements. In birds, multiple ovarian follicles develop inside the female at the same time, resulting in a trade-off of resources among them and potentially limiting maternal ability for sex-specific allocation. We compared resource acquisition among oocytes in relation to their future sex and ovulation order in two populations of house finches with contrasting sex-biased maternal strategies. In a native Arizona population, where mothers do not bias offspring sex in relation to ovulation order, the male and female oocytes did not show sex-specific trade-offs of resources during growth and there was no evidence for spatial or temporal segregation of male and female oocytes in the ovary. In contrast, in a recently established Montana population where mothers strongly bias offspring sex in relation to ovulation order, we found evidence for both intra-sexual trade-offs among male and female oocytes and sex-specific clustering of oocytes in the ovary. We discuss the importance of sex-specific resource competition among offspring for the evolution of sex-ratio adjustment and sex-specific maternal resource allocation.
在繁殖多只后代的物种中，父母需要在同时生长且生长需求往往不同的幼崽之间分配资源。在鸟类中，雌性体内会同时发育多个卵巢卵泡，这导致它们之间存在资源权衡，并且可能限制母体进行性别特异性分配的能力。我们比较了两种具有不同性别偏向母体策略的家朱雀种群中，卵母细胞获取资源的情况与其未来性别和排卵顺序的关系。在亚利桑那州的本地种群中，母亲不会根据排卵顺序偏向后代性别，雄性和雌性卵母细胞在生长过程中没有表现出性别特异性的资源权衡，并且没有证据表明卵巢中雄性和雌性卵母细胞存在空间或时间上的隔离。相比之下，在最近建立的蒙大拿州种群中，母亲会根据排卵顺序强烈偏向后代性别，我们发现了雄性和雌性卵母细胞之间存在性别内权衡以及卵巢中卵母细胞存在性别特异性聚集的证据。我们讨论了后代之间性别特异性资源竞争对于性别比例调整和性别特异性母体资源分配进化的重要性。
