活跃性和社会性对中华倒刺鲃集群行为的影响

为考察群体中不同的个性组成对鱼类集群行为的影响及其内在机制，选取中华倒刺鲃(Spinibarbus sinensis)幼鱼为实验对象，依次测定其活跃性和社会性，随后分别根据活跃性和社会性的高低分为高、低和混合活跃性(或社会性)鱼群，考察鱼群中不同个性组成对集群时的整体运动特征以及每尾鱼的个体运动特征的影响。研究发现：(1)中华倒刺鲃的个性特征稳定且个体间变异较大；(2)高活跃性鱼群的运动时间比和速度同步性均大于低活跃性鱼群，而混合鱼群位于二者之间且与两个同质性鱼群均无显著差异；高社会性鱼群速度同步性显著小于低社会性和混合社会性鱼群，而后两者之间没有显著差异。(3)活跃性特征与集群运动时每尾鱼的运动特征(速度及其同步性等)相关，社会性特征不仅与上述运动特征关联，还与凝聚力大小(距鱼群质心距离)相关。研究表明：(1)鱼群的活跃性和社会性组成均对集群行为产生重要影响，但其内在机制截然不同。主要表现为：就活跃性而言，群体的运动状态是由群体中所有成员共同决定(平均决定机制);就社会性而言，少数低社会性成员对鱼群的运动水平表现有着主导作用(少数决定机制);(2)实验鱼的活跃性在集群行为中得到了较大...

Effects of activity and sociability on shoaling behavior of Spinibarbus sinensis

Animal personalities are defined as consistent individual differences in behaviors across contexts and time. Recently, the ecological relevance of personalities in fish species has drawn much attention from behavioral ecologists, and scientists assumed that how fish group members adjust their personalities thus to maintain consensus direction alignment and speed synchronization during shoaling might be of utmost importance in the field of animal behavior. To investigate the effect of personality composition on the characteristics of shoaling behavior and its internal mechanism in juvenile Qingbo (Spinibarbus sinensis), we measured the personality traits (i.e. activity and sociability), the collective motion of fish shoals (six individuals each shoal and 14 shoals each treatment) with different personality composition (proactive, reactive and heterogenous personality shoals), and the individuality of motion of each group member. The main results are as follows:(1) Qingbo showed stable personality traits with relatively large inter-individual variation indicated by high intraclass correlation coefficient and large coefficient of variation. (2) The high-activity shoals presented more percent time spent moving (approximately 18%) and higher synchronization of swimming speed (approximately 3%) compared to those of low-activity shoals, whereas there was no significant difference between either homogeneous shoal and the heterogenous personality shoal. Furthermore, the synchronization of swimming speed of high-sociability shoal was significantly lower than those of low-activity (approximately 4%) and heterogenous shoals (approximately 3%), whereas there was no significant difference in the latter two treatments. (3) The activity trait was positively correlated with the motion characteristics (such as swimming speed and its synchronization) of each group member during shoaling. The sociability trait was not only correlated (negatively) with above mentioned motion characteristics, but also negatively correlated with the group cohesion. The results suggest that:(1) the personality composition has profound effect on shoaling behavior, but with distinctly different underlying mechanisms. The shoaling behavior characteristics of the group comprised members with different activity trait are mainly determined by all the members of the group, i.e. average-determined mechanism. However, the shoaling behavior characteristics is mainly determined by a few members with the lowest sociability score, i.e. minority-determined mechanism. (2) The activity trait of the experimental fish can withhold to a large extend which might be the fundament of the average-determined mechanism. However, the positive correlation between sociability trait and group cohesion might be at least one reason for the minority-determined mechanism. In all, the stable personality with larger inter-individual variation, the close relationship between personality traits and the motion characteristics, and the complicated mechanism underlying the relationship might beneficial for Qingbo to fulfill their physiological activities under a changeable environment.