Cornell Lab of Ornithology, Cornell University, 159 Sapsucker Woods Road, Ithaca, USA.
School of Environmental Sciences, University of Liverpool, Liverpool, UK.
Proc Biol Sci. 2020 Dec 9;287(1940):20202381. doi: 10.1098/rspb.2020.2381.
Carry-over effects describe the phenomenon whereby an animal's previous conditions influence its subsequent performance. Carry-over effects are unlikely to affect individuals uniformly, but the factors modulating their strength are poorly known. Variation in the strength of carry-over effects may reflect individual differences in pace-of-life: slow-paced, shyly behaved individuals are thought to favour an allocation to self-maintenance over current reproduction, compared to their fast-paced, boldly behaved conspecifics (the pace-of-life syndrome hypothesis). Therefore, detectable carry-over effects on breeding should be weaker in bolder individuals, as they should maintain an allocation to reproduction irrespective of previous conditions, while shy individuals should experience stronger carry-over effects. We tested this prediction in black-legged kittiwakes breeding in Svalbard. Using miniature biologging devices, we measured non-breeding activity of kittiwakes and monitored their subsequent breeding performance. We report a number of negative carry-over effects of non-breeding activity on breeding, which were generally stronger in shyer individuals: more active winters were followed by later breeding phenology and poorer breeding performance in shy birds, but these effects were weaker or undetected in bolder individuals. Our study quantifies individual variability in the strength of carry-over effects on breeding and provides a mechanism explaining widespread differences in individual reproductive success.
残留效应描述了动物先前的状态会影响其后续表现的现象。残留效应不太可能均匀地影响个体，但调节其强度的因素知之甚少。残留效应强度的变化可能反映了个体生活节奏的差异：与快速、大胆的同类相比，生活节奏较慢、行为害羞的个体可能更倾向于将资源分配给自己的维持，而不是当前的繁殖（生活节奏综合征假说）。因此，在更大胆的个体中，繁殖的可检测残留效应应该较弱，因为它们应该不顾先前的条件维持对繁殖的分配，而害羞的个体应该经历更强的残留效应。我们在斯瓦尔巴群岛繁殖的黑腿海鸥中检验了这一预测。我们使用微型生物记录设备测量了海鸥的非繁殖活动，并监测了它们随后的繁殖表现。我们报告了一些非繁殖活动对繁殖的负面残留效应，这些效应在更害羞的个体中通常更强：冬季活动较多的海鸥随后会出现繁殖物候期较晚和繁殖表现较差的情况，但在更大胆的个体中，这些效应较弱或无法检测到。我们的研究量化了繁殖残留效应强度的个体可变性，并提供了一种解释个体繁殖成功率广泛差异的机制。
