Guenther A, Trillmich F
Department of Animal Behavior, University of Bielefeld, Bielefeld, Germany.
Department of Animal Behavior, University of Bielefeld, Bielefeld, Germany.
Physiol Behav. 2015 Jun 1;145:22-8. doi: 10.1016/j.physbeh.2015.03.026. Epub 2015 Mar 20.
Many aspects of an animal's early life potentially contribute to long-term individual differences in physiology and behaviour. From several studies on birds and mammals it is known that the early family environment is one of the most prominent factors influencing early development. Most of these studies were conducted on highly altricial species. Here we asked whether in the highly precocial cavy (Cavia aperea) the size rank within a litter, i.e. whether an individual is born as the heaviest, the lightest or an intermediate sibling, affects personality traits directly after birth and after independence. Furthermore, we investigated whether individual states (early growth, baseline cortisol and resting metabolic rate) differ between siblings of different size ranks and assessed their relation to personality traits. Siblings of the same litter differed in personality traits as early as three days after birth. Pups born heaviest in the litter were more explorative and in general more risk-prone than their smaller siblings. Physiological state variables were tightly correlated with personality traits and also influenced by the size rank within litter, suggesting that the size relative to littermates constitutes an important factor in shaping an individual's developmental trajectory. Our data add valuable information on how personalities are shaped during early phases of life and indicate the stability of developmentally influenced behavioural and physiological traits.
动物早期生活的许多方面都可能导致其生理和行为的长期个体差异。从对鸟类和哺乳动物的多项研究中可知，早期家庭环境是影响早期发育的最突出因素之一。这些研究大多是针对高度晚成雏物种进行的。在此，我们探讨在高度早熟的天竺鼠（Cavia aperea）中，一窝幼崽内的体型排名，即个体出生时是最重、最轻还是中间体重的兄弟姐妹，是否会在出生后及独立后直接影响其个性特征。此外，我们研究了不同体型排名的兄弟姐妹之间的个体状态（早期生长、基础皮质醇和静息代谢率）是否存在差异，并评估它们与个性特征的关系。同一窝的兄弟姐妹在出生仅三天后个性特征就有所不同。在一窝中出生时最重的幼崽比其体型较小的兄弟姐妹更具探索性，总体上也更倾向于冒险。生理状态变量与个性特征紧密相关，并且也受到窝内体型排名的影响，这表明相对于同窝兄弟姐妹的体型是塑造个体发育轨迹的一个重要因素。我们的数据为个性在生命早期阶段如何形成提供了有价值的信息，并表明受发育影响的行为和生理特征具有稳定性。
