Data from: Oxidative status and fitness components in the Seychelles warbler

1. Oxidative damage, caused by reactive oxygen species during aerobic respiration, is thought to be an important mediator of life-history trade-offs. To mitigate oxidative damage, antioxidant defence mechanisms are deployed, often at the cost of resource allocation to other body functions. Both reduced resource allocation to body functions and direct oxidative damage may decrease individual fitness, through reducing survival and/or reproductive output. 2. The oxidative costs of reproduction have gained much attention recently, but few studies have investigated the long-term consequences of oxidative damage on survival and (future) reproductive output under natural conditions. 3. Using a wild population of the cooperatively breeding Seychelles warbler (Acrocephalus sechellensis), we tested the prediction that high levels of reactive oxygen species, or high antioxidant investments to avoid oxidative damage, have fitness consequences because they reduce survival and/or reproductive output. 4. We found that individuals with higher circulating non-enzymatic antioxidant capacity had a lower probability of surviving until the next year. However, neither current reproductive output, nor future reproductive output in the surviving individuals, was associated with circulating non-enzymatic antioxidant capacity or oxidative damage. 5. The negative relationship between antioxidant capacity and survival that we observed concurs with the findings of an extensive comparative study on birds, however the mechanisms underlying this association remain to be resolved.1. 有氧呼吸过程中由活性氧（reactive oxygen species）介导产生的氧化损伤，被认为是生活史权衡（life-history trade-offs）的重要调控因子。为缓解氧化损伤，生物会启动抗氧化防御机制（antioxidant defence mechanisms），但这通常会以向其他身体功能分配资源为代价。向身体功能的资源分配减少，以及直接的氧化损伤，均可能通过降低个体存活率和/或繁殖产出，损害个体适合度（individual fitness）。 2. 繁殖的氧化代价近年来受到广泛关注，但鲜有研究探讨自然条件下氧化损伤对存活率以及（未来）繁殖产出的长期影响。 3. 本研究以合作繁殖的野生塞舌尔莺（Acrocephalus sechellensis）种群为研究对象，验证了这一预测：高水平的活性氧，或是为规避氧化损伤而投入的大量抗氧化资源，会通过降低存活率和/或繁殖产出，对个体适合度产生影响。 4. 研究发现，循环中非酶抗氧化能力（circulating non-enzymatic antioxidant capacity）更高的个体，存活至次年的概率更低。然而，无论是当前繁殖产出，还是存活个体的未来繁殖产出，均与循环中非酶抗氧化能力或氧化损伤无显著关联。 5. 本研究观察到的抗氧化能力与存活率之间的负相关关系，与一项针对鸟类的大规模比较研究结果一致，但该关联背后的具体机制仍有待进一步解析。