Petrullo Lauren, Delaney David, Boutin Stan, Lane Jeffrey E, McAdam Andrew G, Dantzer Ben
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, 857192, AZ, USA.
Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, 803023, CO, USA.
Proc Biol Sci. 2024 Apr 30;291(2021):20232681. doi: 10.1098/rspb.2023.2681. Epub 2024 Apr 24.
Early-life adversity, even when transient, can have lasting effects on individual phenotypes and reduce lifespan across species. If these effects can be mitigated by a high-quality later-life environment, then differences in future resources may explain variable resilience to early-life adversity. Using data from over 1000 wild North American red squirrels, we tested the hypothesis that the costs of early-life adversity for adult lifespan could be offset by later-life food abundance. We identified six adversities that reduced juvenile survival in the first year of life, though only one-birth date-had continued independent effects on adult lifespan. We then built a weighted early-life adversity (wELA) index integrating the sum of adversities and their effect sizes. Greater weighted early-life adversity predicted shorter adult lifespans in males and females, but a naturally occurring food boom in the second year of life ameliorated this effect. Experimental food supplementation did not replicate this pattern, despite increasing lifespan, indicating that the buffering effect of a future food boom may hinge on more than an increase in available calories. Our results suggest a non-deterministic role of early-life conditions for later-life phenotype, highlighting the importance of evaluating the consequences of early-life adversity in the context of an animal's entire life course.
早期生活逆境，即使是短暂的，也会对个体表型产生持久影响，并缩短跨物种的寿命。如果这些影响可以通过高质量的后期生活环境得到缓解，那么未来资源的差异可能解释了对早期生活逆境的不同恢复力。利用来自1000多只野生北美红松鼠的数据，我们检验了这样一个假设，即成年寿命因早期生活逆境而付出的代价可以通过后期食物丰富度来抵消。我们确定了六种会降低幼崽出生后第一年存活率的逆境，不过只有一个——出生日期——对成年寿命有持续的独立影响。然后，我们构建了一个加权早期生活逆境（wELA）指数，综合了逆境及其效应大小的总和。更高的加权早期生活逆境预示着雄性和雌性成年寿命更短，但出生后第二年自然发生的食物繁荣缓解了这种影响。实验性食物补充并没有重现这种模式，尽管延长了寿命，这表明未来食物繁荣的缓冲效应可能不仅仅取决于可获得热量的增加。我们的结果表明早期生活条件对后期生活表型具有非决定性作用，突出了在动物整个生命历程的背景下评估早期生活逆境后果的重要性。
