Food availability affects adult survival trajectories depending on early developmental conditions

Food availability modulates survival in interaction with (for example) competition, disease and predators, but to what extent food availability in natural populations affects survival independent of these factors is not well known. We tested the effect of food availability on lifespan and actuarial senescence in a large population of captive zebra finches by increasing the effort required to obtain food, reflecting natural contrasts in food availability. Food availability may not affect all individuals equally and we therefore created heterogeneity in phenotypic quality by raising birds with different numbers of siblings. Low food availability had no effect on lifespan for individuals from benign developmental conditions (raised in small broods), but shortened lifespan for individuals from harsh developmental conditions. The lifespan difference arose through higher baseline mortality rate of individuals from harsh developmental conditions, despite a decrease in the rate of actuarial sen...

食物可获得性会与（例如）竞争、疾病与捕食者等因素相互作用，共同调控存活过程，但目前学界对于自然种群中食物可获得性在独立于上述因素的前提下，对存活的影响程度仍未得到充分阐明。本研究通过提升获取食物所需的付出以模拟自然环境中食物可获得性的差异，在一个大型圈养斑胸草雀种群中，探究了食物可获得性对寿命与衰老速率（actuarial senescence）的影响。食物可获得性对不同个体的影响可能并不均等，因此本研究通过让雏鸟在不同同胞数量的巢群中抚育成长，构建了表型质量（phenotypic quality）的异质性。对于发育环境适宜（即于小型巢群中抚育长大）的个体而言，低食物可获得性对其寿命无显著影响；但对于发育环境严苛（即于大型巢群中抚育长大）的个体，低食物可获得性会缩短其寿命。该寿命差异源于发育环境严苛的个体拥有更高的基础死亡率，尽管其衰老速率有所下降……