Data from: Oxidative status and social dominance in a wild cooperative breeder

1. Oxidative stress has been proposed as a key mediator of life-history trade-offs, yet the social factors that affect patterns of oxidative states amongst individuals in animal societies remain virtually unexplored. 2. This is important, as rank-related differences in reproductive effort in many social species have the potential to generate, or indeed arise from, differences in oxidative state across dominance classes. 3. Here, we examine rank-related variation in oxidative states before and after a lengthy breeding season in a wild cooperatively breeding bird with high reproductive skew in the semi-arid zone of Southern Africa; the white-browed sparrow weaver (Plocepasser mahali). 4. Our findings reveal that prior to breeding, neither sex showed rank-related differences in markers of oxidative damage or antioxidant protection, suggesting that dominants’ reproductive monopolies do not arise from superior pre-breeding oxidative states. 5. After breeding, however, females (who provision young at higher rates than males) suffered elevated oxidative damage, and dominant females (the only birds to lay and incubate eggs, and the primary nestling provisioners) experienced differential declines in antioxidant protection. 6. While males also showed reduced antioxidant capacity after breeding, this decline was rank-independent and not associated with elevated oxidative damage. 7. Our findings suggest that divisions of labour in animal societies can leave the hardest-working classes differentially exposed to oxidative stress, raising the possibility of hitherto unexplored impacts on health and ageing in social species.1. 氧化应激（Oxidative stress）已被提出是生活史权衡的关键介导因子，但目前几乎尚未有研究探索影响动物社会中个体氧化状态模式的社会因素。 2. 这一点至关重要，因为诸多社会物种中与社会等级相关的繁殖投入差异，既可能催生不同优势层级间的氧化状态差异，也可能实则由这类氧化状态差异所引发。 3. 本研究以分布于非洲南部半干旱区域、具有高度繁殖偏倚的野生合作繁殖鸟类——白眉织布雀（Plocepasser mahali）为研究对象，调查了其在漫长繁殖季前后与社会等级相关的氧化状态变异情况。 4. 研究结果显示，繁殖前雌雄个体的氧化损伤标志物与抗氧化保护水平均未表现出与社会等级相关的差异，这表明优势个体的繁殖垄断并非源于繁殖前更优的氧化状态。 5. 然而繁殖结束后，繁殖幼鸟投入率高于雄性的雌性个体出现了氧化损伤水平升高的情况；而作为唯一产卵、孵卵且主要参与育雏的优势雌性，其抗氧化保护水平出现了差异性下降。 6. 尽管雄性个体在繁殖后抗氧化能力也有所下降，但这种下降与社会等级无关，且未伴随氧化损伤水平的升高。 7. 本研究结果表明，动物社会中的劳动分工可使劳动强度最高的群体差异化地暴露于氧化应激之中，这为探索社会物种此前未被发掘的健康与衰老影响机制提供了全新可能。