Centre for Ecology and Hydrology, Natural Environment Research Council, Bush Estate, Penicuik, Midlothian EH26 0QB, United Kingdom.
Gen Comp Endocrinol. 2012 Apr 1;176(2):151-7. doi: 10.1016/j.ygcen.2012.01.006. Epub 2012 Jan 20.
Physiological mechanisms mediating carryover effects, wherein events or activities occurring in one season, habitat, or life-history stage affect important processes in subsequent life-history stages, are largely unknown. The mechanism most commonly invoked to explain carryover effects from migration centres on the acquisition and utilization of resources (e.g. body mass, or individual 'condition'). However, other mechanisms are plausible, e.g. trade-offs reflecting conflict or incompatibility between physiological regulatory systems required for different activities or life-history stages (migration vs. reproduction). Here we show that in female black-browed albatrosses (Thalassarche melanophris) the decision to reproduce or to defer reproduction, made prior to their arrival at breeding colonies after long-distance migration, is associated with condition-related (body mass, hematocrit, hemoglobin concentrations) and hormonal (progesterone, testosterone, estrogen-dependent yolk precursors) traits. In contrast, reproductive success showed little association with condition but showed significant associations with the steroidogenic processes underlying follicle development. Specifically, success was determined by reproductive readiness via differences in steroid hormones and hormone-dependent traits. Successful albatrosses were characterized by high progesterone and high estradiol-dependent yolk precursor levels, whereas failed albatrosses had high testosterone and low yolk precursor levels. Results are discussed with reference to migratory carryover effects and how these can differentially affect the physiologies influencing reproductive decisions and reproductive success.
生理机制介导的延续效应，即在一个季节、栖息地或生活史阶段发生的事件或活动影响后续生活史阶段的重要过程，在很大程度上是未知的。最常被用来解释迁徙引起的延续效应的机制是关于资源的获取和利用（例如，体重或个体“状况”）。然而，其他机制也是合理的，例如，反映不同活动或生活史阶段所需的生理调节系统之间的冲突或不兼容性的权衡（迁徙与繁殖）。在这里，我们表明，在雌性黑眉信天翁（Thalassarche melanophris）中，在经过长途迁徙到达繁殖地之前，决定繁殖或推迟繁殖的决定与与状况相关的（体重、血细胞比容、血红蛋白浓度）和激素（孕酮、睾丸激素、雌激素依赖性卵黄前体）特征有关。相比之下，繁殖成功与状况的相关性较小，但与卵泡发育的类固醇生成过程有显著相关性。具体而言，通过类固醇激素和激素依赖性特征的差异来确定通过生殖准备来确定成功。成功的信天翁的特征是孕酮和雌激素依赖性卵黄前体水平高，而失败的信天翁的特征是睾丸激素和低卵黄前体水平高。结果参考了迁徙的延续效应，以及这些效应如何不同地影响影响生殖决策和生殖成功的生理机能。
