Department of Animal Behaviour, Bielefeld University, Germany; GELIFES - Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands.
GELIFES - Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands.
Horm Behav. 2018 Jul;103:129-139. doi: 10.1016/j.yhbeh.2018.06.010. Epub 2018 Jul 3.
Despite the growing evidence for the importance of developmental experiences shaping consistent individual differences in behaviour and physiology, the role of endocrine factors underlying the development and maintenance of such differences across multiple traits, remains poorly understood. Here, we investigated how an experimental manipulation of circulating glucocorticoids during early adolescence affects behavioural and physiological variation and covariation later in life in the precocial cavy (Cavia aperea). Plasma cortisol concentrations were experimentally elevated by administering cortisol via food for 3 weeks. Struggle docility, escape latency, boldness, exploration and social behaviour were then tested three times after individuals attained sexual maturity. In addition, blood samples were taken repeatedly to monitor circulating cortisol concentrations. Exogenous cortisol affected mean trait expression of plasma cortisol levels, struggle docility and escape latency. Repeatability of cortisol and escape latency was increased and repeatability of struggle docility tended to be higher (approaching significance) in treated individuals. Increased repeatability was mainly caused by an increase of among-individual variance. Correlations among docility, escape latency and cortisol were stronger in treated animals compared to control animals. These results suggest that exposure to elevated levels of cortisol during adolescence can alter animal personality traits as well as behavioural syndromes. Social and risk-taking traits showed no correlation with cortisol levels and were unaffected by the experimental manipulation, indicating behavioural modularity. Taken together, our data highlight that cortisol can have organising effects during adolescence on the development of personality traits and behavioural syndromes, adding to the increasing evidence that not only early life but also adolescence is an important sensitive period for behavioural development.
尽管越来越多的证据表明，发育经历对行为和生理的一致性个体差异具有重要影响，但内分泌因素在多种特征的发展和维持中的作用仍知之甚少。在这里，我们研究了青春期早期循环皮质醇的实验操作如何影响早熟豚鼠（Cavia aperea）一生中行为和生理变化的变异性和协同性。通过食物给个体喂食皮质醇 3 周，来提高血浆皮质醇浓度。在个体达到性成熟后，我们进行了三次挣扎温顺度、逃避潜伏期、大胆度、探索和社会行为的测试。此外，还多次采集血液样本以监测循环皮质醇浓度。外源性皮质醇影响血浆皮质醇水平、挣扎温顺度和逃避潜伏期的平均特征表达。皮质醇和逃避潜伏期的可重复性增加，而处理个体的温顺度可重复性趋于更高（接近显著水平）。可重复性的增加主要是由于个体间方差的增加。与对照组相比，处理组动物的温顺度、逃避潜伏期和皮质醇之间的相关性更强。这些结果表明，青春期暴露于高水平的皮质醇会改变动物的个性特征和行为综合征。社会和冒险特质与皮质醇水平没有相关性，并且不受实验操作的影响，这表明行为具有模块性。总的来说，我们的数据表明，皮质醇在青春期对个性特征和行为综合征的发展具有组织作用，这增加了越来越多的证据表明，不仅是生命早期，而且青春期也是行为发展的重要敏感时期。
