Group hunting where two or more individuals chase the same prey occurs in various vertebrate clades. Its evolution has typically been attributed to the resulting increased prey capture rate. Indeed, many studies have documented positive correlations between the number of individuals and probability of success, suggesting that joint hunting is cooperative. However, all existing data on vertebrates are based on field observations and hence cannot control for factors that may also influence hunting success, such as variation in habitat structure, hunting motivation or prey state. Therefore, we conducted controlled laboratory experiments to test whether hunting performance is affected by group size in the group-hunting yellow saddle goatfish. We presented invertebrate prey in an artificial coral reef and measured hunting performance as a function of manipulated group size, ranging from one to four individuals. We found that individuals hunting alone failed to catch the prey within the trial time limit significantly more often than groups did. Furthermore, we found that time until capture depended on group size, with singletons being slowest and groups of four fastest. With few exceptions, group members were approximately equally likely to catch prey. Hunting success as a singleton did not predict an individual's prey capture probability when in a group, suggesting that group hunting involves some producer–scrounger dynamics. In conclusion, while the experiment cannot address the question of how group size affects individual net calorie intake, the results show that groups are more successful at hunting than singletons are.

中文翻译：

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实验室实验揭示了群体规模对黄鞍山鲇（Parupeneus cyclostomus）捕猎性能的影响

两个或多个个体追逐同一猎物的群体狩猎发生在各种脊椎动物进化枝中。它的进化通常归因于由此增加的猎物捕获率。事实上，许多研究记录了个体数量与成功概率之间的正相关关系，表明联合狩猎是合作的。然而，关于脊椎动物的所有现有数据均基于实地观察，因此无法控制也可能影响狩猎成功的因素，例如栖息地结构、狩猎动机或猎物状态的变化。因此，我们进行了受控的实验室实验，以测试群体狩猎黄鞍山鲇的狩猎性能是否受群体规模的影响。我们在人造珊瑚礁中展示了无脊椎动物猎物，并测量了作为受操纵群体规模的函数的狩猎性能，范围从 1 到 4 个个体。我们发现单独狩猎的个体未能在试验时限内捕获猎物的频率明显高于群体。此外，我们发现捕获前的时间取决于组的大小，单例最慢，四人组最快。除了少数例外，群体成员捕获猎物的可能性大致相同。作为单身人士的狩猎成功并不能预测个体在群体中捕获猎物的概率，这表明群体狩猎涉及一些生产者 - 掠夺者的动态。总之，虽然该实验无法解决团体规模如何影响个人净卡路里摄入量的问题，