Data from: Effects of developmental conditions on growth, stress, and telomeres in black-legged kittiwake chicks

Early-life conditions can drive ageing patterns and life history strategies throughout the lifespan. Certain social, genetic, and nutritional developmental conditions are more likely to produce high-quality offspring: those with good likelihood of recruitment and productivity. Here we call such conditions “favored states” and explore their relationship with physiological variables during development in a long-lived seabird, the black-legged kittiwake (Rissa tridactyla). Two favored states were experimentally generated by manipulation of food availability and brood size, while hatching order and sex were also explored as naturally generating favored states. Thus, the favored states we explored were high food availability, lower levels of sibling competition, hatching first, and male sex. We tested the effects of favored developmental conditions on growth, stress, telomere length (a molecular marker associated with lifespan), and nestling survival. Generation of favored states through manipulation of both the nutritional and social environments furthered our understanding of their relative contributions to development and phenotype: increased food availability led to larger body size, reduced stress, and higher antioxidant status, while lower sibling competition (social environment) led to lower telomere loss and longer telomere lengths in fledglings. Telomere length predicted nestling survival, and wing growth was also positively correlated with telomere length, supporting the idea that telomeres may indicate individual quality, mediated by favored states.

生命早期环境条件可调控个体终生的衰老模式与生活史策略。部分社会、遗传与营养发育条件更易培育出优质后代——即具备较高种群补充潜力与繁殖效能的个体。本研究将此类条件定义为"优势发育状态（favored states）"，并以长寿命海鸟三趾鸥（Rissa tridactyla）为研究对象，探究其发育阶段的生理变量与该状态间的关联。本研究通过调控食物可获得性与育雏规模，人为构建了两种优势发育状态；同时将孵化顺序与雏鸟性别作为天然的优势发育状态影响因素开展探究。因此本研究涉及的优势发育状态包括：高食物可获得性、低同胞竞争程度、率先孵化以及雄性雏鸟。本研究检测了优势发育状态对雏鸟生长、应激水平、端粒长度（telomere length，与寿命相关的分子标记物）以及雏鸟存活率的影响。通过同时调控营养与社会环境构建优势发育状态，有助于我们明晰二者对个体发育与表型的相对贡献：提升食物可获得性可使雏鸟体型更大、应激水平更低且抗氧化能力更强；而降低同胞竞争（社会环境因素）则可减少离巢幼鸟的端粒损耗，使其端粒长度更长。端粒长度可预测雏鸟存活率，翼部生长与端粒长度亦呈正相关，这支持了"端粒可反映个体质量，且该关联受优势发育状态介导"的观点。