Intermittent fasting (IF) is receiving increasing attention as an alternative to continuous restriction of calories because of its benefits in aging-related disease prevention and lifespan extension. However, whether both sexes with sexual dimorphism have similar response to IF have rarely been assayed. In this study, we determined how different durations of IF influence lifespan and whether males and females differed in their responses to IF. We also tested whether there is a trade-off between lifespan and lifetime reproduction in females under IF. We used spider mite Tetranychus urticae, with female-biased sexual size dimorphism (SSD), as our model species to investigate the survival and lifespan difference of both sexes at different durations of IF regimes, and explore the association between longevity and fecundity in females within and across treatments. The lifespan of females increased before intermediate level of IF and then decreased afterwards, but males showed a decreasing trend in lifespan when subjected to IF. Within each treatment, female longevity was positively associated with their fecundity. However, the females fed ad libitum had a higher lifetime fecundity with a shorter lifespan, whereas mites fed 50% IF outlived ad libitum fed ones with lower fecundity because of the later onset of reproduction and lower daily fecundity, showing clear survival and reproduction trade-off when variation of resource availability enhanced across treatments. We showed sex-specific response to IF in lifespan, indicating that sexes with SSD have different optimal level of IF. These findings showed trade-off between survival and reproduction between treatments but not within treatments, suggesting that variation in resource availability is the necessary precondition for life history trade-off, and IF extends lifespan of females at the cost of reproductive success.

中文翻译：

---

间歇性禁食对红蜘蛛叶螨寿命和繁殖的性别和持续时间依赖性影响

间歇性禁食 (IF) 作为持续限制卡路里的替代方法，正受到越来越多的关注，因为它有利于预防与衰老相关的疾病和延长寿命。然而，很少有关于两性是否对 IF 有相似反应的研究。在这项研究中，我们确定了 IF 的不同持续时间如何影响寿命，以及男性和女性对 IF 的反应是否不同。我们还测试了 IF 下女性的寿命和终生繁殖之间是否存在权衡。我们使用具有雌性偏向性大小二态性 (SSD) 的叶螨 Tetranychus urticae 作为我们的模型物种，以研究在不同持续时间的 IF 制度下两性的生存和寿命差异，并探索治疗范围内和治疗期间女性长寿和生育能力之间的关系。IF中级前雌性寿命先增加后降低，而雄性在IF作用下寿命呈递减趋势。在每种治疗中，女性的寿命与她们的繁殖力呈正相关。然而，随意喂食的雌性具有较高的终生繁殖力和较短的寿命，而喂食 50% IF 的螨虫由于繁殖时间较晚和每日繁殖力较低而比随意喂食较低繁殖力的螨虫寿命长，显示出明显的生存和繁殖贸易-当资源可用性的变化跨处理增强时关闭。我们在生命周期中显示了对 IF 的性别特异性反应，表明 SSD 的性别具有不同的最佳 IF 水平。