Data from: Who directs group movement? Leader effort vs follower preference in stickleback fish of different personality

During collective movement, bolder individuals often emerge as leaders. Here, we investigate whether this reflects a greater propensity of bold individuals to initiate movement, or a preference for shy individuals to follow a bolder leader. We set up trios of stickleback fish comprising a focal individual who was either bold or shy, and one other individual of each personality. We then recorded the movements of all individuals in and out of cover in a foraging context to determine how assiduously the focal fish followed the movements of each other partner. We found that a shy focal fish preferred to follow a leader whose personality matched its own, but we did not detect such a difference in bold fish. Despite this preference, however, the greater propensity of bold individuals to initiate movements out of cover meant that they successfully led more joint trips. Thus, when offered a choice of leaders, sticklebacks prefer to follow individuals whose personality matches their own, but bolder individuals may, nevertheless, be able to impose their leadership, even among shy followers, simply through greater effort.在集体移动过程中，更大胆的个体往往会成为群体领导者。本研究旨在探究该现象究竟源于大胆个体更高的运动发起倾向，还是源于害羞个体更倾向于追随大胆领导者。我们构建了由三条棘鱼（stickleback）组成的实验组：其中一条为目标个体，其个性分为大胆或害羞两类，其余两条则分别具备大胆与害羞两种个性特质。随后我们在觅食情境下，记录了所有个体在遮蔽处内外的移动情况，以此量化目标个体追随其他同伴移动的专注程度。研究结果显示，以害羞个体为目标的实验组中，目标鱼更倾向于追随个性与自身相符的领导者；而在以大胆个体为目标的实验组中，则未观察到此类偏好差异。尽管存在上述偏好，但大胆个体更高的发起移出遮蔽处运动的倾向，使得它们能够成功主导更多的联合移动行动。综上，当可选择领导者时，棘鱼更倾向于追随个性与自身相符的个体；但即便在害羞的跟随者群体中，大胆个体仍可凭借更高的行动主动性，顺利施加自身的领导权。