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。特定的社会、遗传与营养发育条件更易孕育高质量后代——即具备较高种群补充与繁殖生产力潜力的个体。在此我们将此类条件定义为“偏好状态（favored states）”，并以长寿海鸟黑脚三趾鸥（Rissa tridactyla）为研究对象，探究其发育过程中与生理变量的关联。本研究通过调控食物可获得性与窝雏数，人工构建了两种偏好状态；同时将孵化顺序与性别作为自然产生的偏好状态进行探究。因此本研究所涉及的偏好状态包括：高食物可获得性、较低的同胞竞争水平、率先孵化以及雄性性别。我们检验了偏好发育条件对幼鸟生长、应激水平、端粒长度（一种与寿命相关的分子标记）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偏好状态，有助于深入解析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幼鸟体型更大、应激水平更低且抗氧化状态更强；而降低同胞竞争水平则可减少离巢幼鸟的端粒丢失，延长其端粒长度。端粒长度可预测雏鸟存活率，且翅部生长与端粒长度呈正相关，这支持了端粒可反映个体质量且该效应受偏好发育状态介导的观点。