Point Blue Conservation Science, Petaluma, CA, 94954, USA.
Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Montpellier, France.
Sci Rep. 2019 Mar 4;9(1):3375. doi: 10.1038/s41598-019-39814-x.
Age variation in reproductive performance is well-documented but the mechanisms underlying this variation remain unclear. Foraging efficiency is likely to be a key source of demographic variation as it determines the amount of energy that can be invested in fitness-related activities. Evidence of age-related changes in the foraging efficiency of adult seabirds is scarce and inconsistent. We investigated the effects of age on the foraging efficiency of breeding Adélie penguins, a relatively short-lived seabird species, in order to gain a broader perspective on the processes driving variation in ageing rates. We found support for a positive effect of age, either linear or levelling off at old ages, on both our proxies for daily catch rate and catch per unit effort. Across all age classes, males were more performant foragers than females. We found no strong evidence for differing ageing patterns between sexes or individual quality levels, and no evidence for senescence. We infer that continuous individual improvement could be responsible for a larger amount of the variation in foraging efficiency with age at our study site, compared with selective disappearance of underperforming phenotypes. The different results reported by other studies highlight the need to conduct longitudinal studies across a range of species in different environments.
生殖性能的年龄变化有充分的记录，但这种变化的机制仍不清楚。觅食效率很可能是人口变化的一个关键来源，因为它决定了可以投入到与健康相关的活动中的能量。关于成年海鸟觅食效率随年龄变化的证据很少且不一致。我们研究了年龄对繁殖阿德利企鹅觅食效率的影响，阿德利企鹅是一种相对寿命较短的海鸟，以便更广泛地了解推动衰老率变化的过程。我们发现，年龄对我们的每日捕获率和单位努力捕获量的两个代理变量都有积极的影响，要么是线性的，要么是在老年时趋于平稳。在所有年龄组中，雄性都是比雌性更有能力的觅食者。我们没有发现性别或个体质量水平之间存在不同的衰老模式的有力证据，也没有衰老的证据。我们推断，与表现不佳的表型选择性消失相比，在我们的研究地点，连续的个体改进可能是导致随着年龄的增长觅食效率变化的更大原因。其他研究报告的不同结果强调了需要在不同环境下的一系列物种中进行纵向研究。
