Low heritabilities, but genetic and maternal correlations between red squirrel behaviours.

Consistent individual differences in behaviour, and behavioural correlations within and across contexts, are referred to as animal personalities. These patterns of variation have been identified in many animal taxa and are likely to have important ecological and evolutionary consequences. Despite their importance, genetic and environmental sources of variation in personalities have rarely been characterized in wild populations. We used a Bayesian animal model approach to estimate genetic parameters for aggression, activity and docility in North American red squirrels (Tamiasciurus hudsonicus). We found support for low heritabilities (0.08-0.12), and cohort effects (0.07-0.09), as well as low to moderate maternal effects (0.07-0.15) and permanent environmental effects (0.08-0.16). Finally, we found evidence of a substantial positive genetic correlation (0.68) and maternal effects correlation (0.58) between activity and aggression providing evidence of genetically-based behavioural correlations in red squirrels. These results provide evidence for the presence of heritable variation in red squirrel behaviour, but also emphasize the role of other sources of variation, including maternal effects, in shaping patterns of variation and covariation in behavioural traits.

行为层面稳定的个体差异，以及不同情境内部与跨情境的行为相关性，被称为动物个性（animal personalities）。这类变异模式已在诸多动物类群中被发现，且极可能产生重要的生态与进化效应。尽管其研究意义重大，但学界此前极少针对野生种群中动物个性变异的遗传与环境来源开展系统性表征研究。本研究采用贝叶斯动物模型（Bayesian animal model）方法，对北美红松鼠（Tamiasciurus hudsonicus）的攻击性、活动性与易驯服性的遗传参数进行了估算。研究结果显示，该物种存在较低的遗传力（0.08~0.12）与同龄群效应（0.07~0.09），同时存在低至中等程度的母体效应（0.07~0.15）与永久环境效应（0.08~0.16）。最后，本研究发现活动性与攻击性之间存在显著的正向遗传相关（0.68）与母体效应相关（0.58），这为红松鼠存在基于遗传基础的行为相关性提供了直接证据。上述结果不仅证实了红松鼠行为存在可遗传变异，同时也强调了包括母体效应在内的其他变异来源，在塑造行为性状的变异与协变模式中所发挥的重要作用。