Testing the predictions of energy allocation decisions in the evolution of life‐history trade‐offs
Testing the predictions of energy allocation decisions in the evolution of life‐history trade‐offs
复制标题
测试生命史权衡演化中能量分配决策的预测
DOI：
--
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
W. Hood
中科院分区：
文献类型：
--
作者：
A. Skibiel;J. Speakman;W. Hood
概述1.将更多有限的资源，如能量，分配给当前的繁殖可能会减少可用于躯体维持的能量，并最终可能损害未来的繁殖成功或母体存活(即生殖成本假说)。尽管鸟类的繁殖成本假说得到了一些支持，但对哺乳动物的实证研究很少证明当前和未来的繁殖之间存在权衡。更重要的是，大多数测试最终成本的研究都忽略了确认生殖的近成本是高的。2.我们对哥伦比亚野生地松鼠的产仔大小进行了为期两年的实验研究，以考察繁殖的能量成本和最终适宜成本(即生存和繁殖)。我们预测，饲养增加产仔的雌性将拥有最高的每日能量消耗率，因此将经历较低的存活率或未来的繁殖力。3.增加胎次的雌鼠断奶次数最多，断奶时的窝重最大，其田间代谢率几乎是对照组或减胎率的15倍。与我们的预测相反，更大的母体投资和更高的能量消耗对母体存活或未来繁殖的概率没有负面影响。4.增加胎次的仔猪在哺乳期生长较慢，断奶时体型较小，越冬存活的概率较低。因此，尽管雌性能够在不降低存活率或繁殖力的短期成本的情况下饲养更多的幼崽，但我们的观察表明，对产仔数量的限制并不是由于能量分配的权衡，而是因为较大产仔的后代存活率降低。5.考察作为生活史权衡基础的假设的最接近机制可能具有挑战性，但对于全面理解生活史的演变至关重要。
Summary 1. Allocating a greater amount of limited resources, such as energy, to current reproduction can reduce the amount of energy available for somatic maintenance and can ultimately impair future breeding success or maternal survival (i.e. cost of reproduction hypothesis). Although there is some support for the cost of reproduction hypothesis in birds, few empirical studies of mammals have demonstrated a trade-off between current and future reproduction. More importantly, most studies testing ultimate costs have neglected to confirm that the proximate costs of reproduction are high. 2. We experimentally manipulated litter size in a wild population of Columbian ground squirrels for 2 years to examine both the proximate energetic and ultimate fitness (i.e. survival and breeding) costs of reproduction. We predicted that females raising augmented litters would have the highest rates of daily energy expenditure and as a result would experience lower survival rates or future fecundity. 3. Females raising augmented litters weaned more pups, had the highest litter masses at weaning, and had field metabolic rates that were almost 15 times greater than females raising control or reduced litters. Contrary to our prediction, there were no negative impacts of greater maternal investment and higher energy expenditure on the probability of maternal survival or future reproduction. 4. Pups from augmented litters grew more slowly during the lactation period were smaller at weaning and had a lower probability of survival over-winter. Thus, although females were capable of raising more young than they gave birth to without short-term costs of reduced survival or fecundity, our observations suggest that limitations to litter size are not due to a trade-off in the allocation of energy, but rather due to the reduced survival of offspring from larger litters. 5. Examining the proximate mechanisms hypothesized to underlie life-history trade-offs can be challenging but is critical for a comprehensive understanding of the evolution of life histories.