Abstract：
This study investigated the influence of group size (individual, groups of five, and 20) on the response of common minnow to visual cues created by vertical black and white stripes over time. The stripes were displayed on a monitor either at one end of an experimental tank, while the other was uniform white, or both ends simultaneously. Reponses were compared with a control (stripes absent). Visual cues were pseudo-randomly presented every 15-minutes over six-hours. Three predictions were made: first, due to more efficient flow of information, larger groups would respond more rapidly (Rate of response) to the visual cues. Second, assuming visual cues provide a proxy for structure and larger groups experience greater benefits of group membership due to reduced predatory risk, there will be stronger association (Strength of association and Final association) with stripes for individuals and smaller groups compared with larger groups. Consequently, the association with visual cues exhibited by larger groups would diminish over time compared to smaller, more risk averse groups. As expected, larger groups exhibited a faster Rate of response to visual cues, and individual fish a greater Strength of association compared with the largest group size. Final association, however, was more common for larger groups compared to both smaller groups and individuals. Contrary to the final prediction, responses to visual cues did not decrease over time for any group size, suggesting innate behaviour or an experimental duration insufficient to observe habituation.
摘要：
本研究调查了群体规模的影响(个体，五人组,和20）关于普通小鱼对垂直黑白条纹随时间产生的视觉线索的响应。条纹显示在实验罐一端的监视器上，而另一个是统一的白色，或者两端同时结束。将reponses与对照（无条纹）进行比较。视觉提示在6小时内每15分钟伪随机呈现一次。做出了三个预测:第一,由于更有效的信息流，更大的群体会更快地对视觉线索做出反应(反应率)。第二,假设视觉线索为结构提供了代理，较大的群体由于掠夺性风险降低而获得了更大的群体成员利益，与较大的群体相比，个体和较小组的条纹将有更强的关联（关联强度和最终关联）。因此,与较小群体相比，较大群体表现出的与视觉线索的关联会随着时间的推移而减少，更多的风险厌恶群体。不出所料,较大的群体对视觉线索表现出更快的反应速率，与最大的组相比，单个鱼的关联强度更大。最终协会,然而,与较小的群体和个体相比，较大的群体更常见。与最终预测相反，对于任何组大小，对视觉线索的反应都不会随着时间的推移而减少，暗示先天行为或实验持续时间不足以观察习惯。
