Polyphenism predicts actuarial senescence and lifespan in tiger salamanders
Polyphenism predicts actuarial senescence and lifespan in tiger salamanders
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DOI：
10.1111/1365-2656.14048
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发表时间：
2024-01-27
影响因子：
4.8
通讯作者：
Whiteman，Howard H.
中科院分区：
文献类型：
--
作者：
Cayuela，Hugo;Lackey，Alycia C. R.;Whiteman，Howard H.
精算衰老（以下称为“衰老”）通常在种内水平上表现出广泛的变化。表型可塑性可能在衰老率（即死亡率随年龄增加的增长率）的个体间异质性中发挥着核心作用，尽管我们对这个主题的了解仍然非常零散。多型现象是表型可塑性的独特亚型，其中同一基因型产生多个离散的表型，可能会提供出色的研究系统来研究可塑性是否以及如何影响自然界的衰老速率。在这项研究中，我们研究了兼性幼态性是否影响蝾螈Ambystoma mavortium nebulosum的衰老速率。兼性幼体现象是世界范围内数十种有尾动物中发现的一种独特的多型现象，它导致产生两种离散的、环境诱导的表型：变态个体和幼体个体。我们利用了一组广泛的捕获-再捕获数据（8948 只个体，24 年的监测），并使用多状态捕获-再捕获模型和贝叶斯年龄依赖性生存模型进行分析。多状态模型显示，幼体发育是我们研究系统中蝾螈最常见的发育途径。贝叶斯年龄依赖性生存模型表明，与变态者相比，幼态者在两性中都加速了衰老，并且成年寿命更短（仅在雌性中）。在幼体中，衰老率和成体寿命在池塘和个体之间也存在差异。身体状况良好、终生繁殖成功率高的女性衰老速度较慢，寿命较长。晚配雌性的寿命也更长，但衰老率与早配雌性相似。此外，身体状况良好的男性比身体状况差的男性寿命更长，尽管他们的衰老率相似。此外，晚育雄性的寿命更长，但出人意料的是，它们比早育雄性的衰老程度更高。总的来说，我们的工作提供了为数不多的经验案例之一，表明环境提示的多型性可能影响自然界脊椎动物的衰老，从而为发育可塑性对衰老的生态和进化后果提供了见解。
Actuarial senescence (called ‘senescence’ hereafter) often shows broad variation at the intraspecific level. Phenotypic plasticity likely plays a central role in among‐individual heterogeneity in senescence rate (i.e. the rate of increase in mortality with age), although our knowledge on this subject is still very fragmentary. Polyphenism—the unique sub‐type of phenotypic plasticity where several discrete phenotypes are produced by the same genotype—may provide excellent study systems to investigate if and how plasticity affects the rate of senescence in nature.In this study, we investigated whether facultative paedomorphosis influences the rate of senescence in a salamander,Ambystoma mavortium nebulosum. Facultative paedomorphosis, a unique form of polyphenism found in dozens of urodele species worldwide, leads to the production of two discrete, environmentally induced phenotypes: metamorphic and paedomorphic individuals. We leveraged an extensive set of capture–recapture data (8948 individuals, 24 years of monitoring) that were analysed using multistate capture–recapture models and Bayesian age‐dependent survival models.Multistate models revealed that paedomorphosis was the most common developmental pathway used by salamanders in our study system. Bayesian age‐dependent survival models then showed that paedomorphs have accelerated senescence in both sexes and shorter adult lifespan (in females only) compared to metamorphs. In paedomorphs, senescence rate and adult lifespan also varied among ponds and individuals. Females with good body condition and high lifetime reproductive success had slower senescence and longer lifespan. Late‐breeding females also lived longer but showed a senescence rate similar to that of early‐breeding females. Moreover, males with good condition had longer lifespan than males with poor body condition, although they had similar senescence rates. In addition, late‐breeding males lived longer but, unexpectedly, had higher senescence than early‐breeding males.Overall, our work provides one of the few empirical cases suggesting that environmentally cued polyphenism could affect the senescence of a vertebrate in nature, thus providing insights on the ecological and evolutionary consequences of developmental plasticity on ageing.