父母的照料受多种内分泌机制的调节。在这些荷尔蒙中,催乳素(PRL)参与父母行为的表达。尽管人们一致认为PRL可以调节父母努力与年龄和身体状况的变化,它在调整父母的努力以适应波动的环境条件中的作用,包括改变捕食压力,仍在等待进一步调查。为了揭示这种知识差距,我们依赖于对雌性常见的eff的长期监测(n=1277次繁殖尝试,2012-2022)在波动的捕食风险下进行孵化,以调查基线PRL水平与女性最低年龄之间的联系,身体状况,离合器尺寸,环境参数(捕食压力,气候,巢微生境)和孵化成功。我们预测老年女性的PRL会更高,那些状态更好或孵化更大的离合器。我们还预测,在具有挑战性的环境条件(高捕食压力或恶劣的气候条件)下筑巢时,雌性会减少父母的努力,转化为降低基线PRL水平。我们还探讨了PRL水平的变化,雌性特征和环境参数与孵化成功有关。根据我们的预测,PRL水平与身体状况和女性年龄呈正相关(在年龄最大的育种者出现衰老下降之前)。然而,我们没有观察到PRL水平因捕食压力升高而降低人群水平或个体水平.在研究期间,人口水平的基线PRL水平反而增加了,随着捕食威胁的上升,而且还会增加女性的身体状况和年龄。虽然我们没有提供基线PRL水平和捕食风险之间直接关联的证据,我们的结果支持这样的观点,即升高的基线PRL水平在内部约束下促进孵化成功(在年轻时,缺乏经验,育种者或孵化大型离合器的人)或限制环境条件(在高捕食压力或恶劣的气候和觅食条件下)。最后,基线PRL水平的低重复性和高年际变异性突出了基线PRL水平的个体内部相当大的灵活性.进一步的研究应该探索父母努力改变环境条件的灵活性,关注基线和应激诱导的PRL水平。
Parental care is regulated by multiple endocrine mechanisms. Among these hormones, prolactin (PRL) is involved in the expression of parental behaviors. Despite the consensus that PRL mediates variation in parental effort with age and body condition, its role in the adjustment of parental effort to fluctuating environmental conditions, including changing predation pressure, still awaits further investigation. To shed light on this knowledge gap, we relied on a long-term monitoring of female common eiders Somateria mollissima (n = 1277 breeding attempts, 2012-2022) incubating under fluctuating predation risk to investigate the link between baseline PRL levels and female minimum age, body condition, clutch size, environmental parameters (predation pressure, climate, nest microhabitat) and hatching success. We predicted that PRL would be higher in older females, those in better condition or incubating larger clutches. We also predicted that females would reduce parental effort when nesting under challenging environmental conditions (high predation pressure or poor climatic conditions), translated into reduced baseline PRL levels. We also explored how variation in PRL levels, female characteristics and environmental parameters were related to hatching success. Following our predictions, PRL levels were positively associated with body condition and female age (before showing a senescent decline in the oldest breeders). However, we did not observe any population-level or individual-level reduction in PRL levels in response to increasing predation pressure. Population-level baseline PRL levels instead increased over the study period, coincident with rising predation threat, but also increasing female body condition and age. While we did not provide evidence for a direct association between baseline PRL levels and predation risk, our results support the idea that elevated baseline PRL levels promote hatching success under internal constraints (in young, inexperienced, breeders or those incubating a large clutch) or constraining environmental conditions (during years of high predation pressure or poor climatic and foraging conditions). Finally, the low repeatability of baseline PRL levels and high interannual variability highlight considerable within-individual flexibility in baseline PRL levels. Further research should explore flexibility in parental effort to changing environmental conditions, focusing on both baseline and stress-induced PRL levels.