Maternal allocation in bison: co-occurrence of senescence, cost of reproduction, and individual quality
Maternal allocation in bison: co-occurrence of senescence, cost of reproduction, and individual quality
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DOI：
10.1890/11-2181.1
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发表时间：
2012-07-01
影响因子：
5
通讯作者：
Towne, E. Gene
中科院分区：
文献类型：
--
作者：
Hamel, Sandra;Craine, Joseph M.;Towne, E. Gene
父母的分配策略是深刻的兴趣，生活史，因为它们直接影响后代的健身，因此是非常有价值的了解人口动态和管理决策。然而，许多关于大型哺乳动物野生种群生殖分配模式的问题仍然没有答案，因为在野外测量分配的挑战。使用9年的纵向数据集的生活史特征的母亲，小牛野牛对，我们确定了相对母体分配（小牛质量比母亲质量）的变化来源，并评估发生的生殖成本与差异的母体分配。我们发现，重的母亲提供了较低的分配，但仍然产生较重的小牛比轻的母亲。年龄较大的女性产生较轻的小牛，往往会减少分配，因为他们的年龄，支持生殖衰老的发生。前一年产下小牛的母亲比前一年没有哺乳的母亲产下的小牛更轻，分配的资源也更少，这揭示了生殖成本。然而，更大的母亲分配并没有减少连续几年繁殖的概率，母亲提供的分配量与她所产生的后代呈正相关，说明了个体的异质性。虽然生活史研究通常被归类为繁殖或个体质量的支持成本，但我们的研究表明，这些对比鲜明的进化力量可以塑造单一性状内的变异。我们的工作表明，许多过程可以在一个种群内共同进化，强调需要整合多个概念，以更好地了解生活史特征的进化。关于野牛群的管理，如果淘汰计划的目标是选择具有最佳性能的动物，本研究表明，管理人员应考虑到母亲的条件和以前的生殖状态时，对少年野牛的淘汰决定。
Parental allocation strategies are of profound interest in life history because they directly impact offspring fitness and therefore are highly valuable for understanding population dynamics and informing management decisions. Yet, numerous questions about reproductive allocation patterns for wild populations of large mammals remain unanswered because of the challenges for measuring allocation in the wild. Using a nine-year longitudinal data set on life-history traits of mother-calf bison pairs, we identified sources of variation in relative maternal allocation (calf mass ratio on mother mass) and assessed the occurrence of reproductive costs associated with differential maternal allocation. We found that heavy mothers provided a lower allocation but still produced heavier calves than light mothers. Older females produced lighter calves and tended to decrease allocation as they aged, supporting the occurrence of reproductive senescence. Mothers that had produced a calf the previous year produced lighter calves and allocated less than mothers that did not lactate the previous year, revealing reproductive costs. However, greater maternal allocation did not reduce the probability of breeding in successive years, and the amount of allocation provided by a mother was positively correlated among the offspring she produced, illustrating individual heterogeneity. Although life-history studies are usually classified as either supporting costs of reproduction or individual quality, our study demonstrates that these contrasting evolutionary forces can shape variation within a single trait. Our work illustrates that many processes can coevolve within a population, emphasizing the need to integrate multiple concepts to better understand the evolution of life-history traits. With regard to management of bison herds, if the goal of culling programs is to select for animals with the best performance, this research suggests that managers should account for the condition and previous reproductive status of mothers when taking culling decisions on juvenile bison.