Understanding the determinants and consequences of predation effort, success and prey responses is important since these factors affect the fitness of predators and prey. When predators are also invasive species, the impacts on prey can be particularly far‐reaching with ultimate ecosystem‐level consequences. However, predators are typically viewed as behaviourally fixed within this interaction and it is unclear how variation in predator social dynamics affects predator–prey interactions. Using the invasive eastern mosquitofish Gambusia holbrooki and a native glass shrimp Paratya australiensis in Australia, we investigated how varying levels of social conflict within predator groups influences predator–prey interactions. By experimentally manipulating group stability of G. holbrooki, we show that rates of social conflict were lower in groups with large size differences, but that routine metabolic rates were higher in groups with large size differences. Predation effort and success did not vary depending on group stability, but in stable groups predation effort by aggressive dominants was greater than subordinates. The anti‐predator responses of prey to the stability of predator groups were mixed. While more prey utilized shelters when exposed to stable compared to unstable groups of predators, a greater proportion were sedentary when predator groups were unstable. Overall, this study demonstrates predator group stability is modulated by differences in body size and can influence prey responses. Further, it reveals a hidden metabolic cost of living in stable groups despite reduced overt social conflict. For invasive species management, it is therefore important to consider the behavioural and physiological plasticity of the invasive predators, whose complex social interactions and metabolic demands can modulate patterns of predator–prey interactions.

中文翻译：

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在社交鱼的稳定和不稳定群体中，捕食者与猎物之间的相互作用和代谢率发生了变化

了解捕食工作，成功和猎物反应的决定因素和后果很重要，因为这些因素会影响捕食者和猎物的适应性。当捕食者也是入侵物种时，对猎物的影响可能会特别深远，最终会给生态系统带来严重后果。但是，捕食者通常被视为行为固定在这种互动中，目前尚不清楚捕食者社会动态的变化如何影响捕食者与猎物的互动。我们使用侵入性的东部蚊鱼Gambusia holbrooki和澳大利亚的本地玻璃虾澳大利亚副天蛾（Patyya australiensis），研究了捕食者群体内部不同程度的社会冲突如何影响捕食者与猎物的相互作用。通过实验控制组的稳定性霍尔布鲁克，我们显示，具有较大差异的人群的社会冲突发生率较低，但是具有较大差异的人群的常规代谢率较高。掠夺的努力和成功并没有随小组的稳定性而变化，但是在稳定的小组中，积极的统治者的掠夺努力要大于下属。捕食者对捕食者群体稳定性的反捕食者反应是混杂的。虽然与不稳定的捕食者相比，更多的被暴露于稳定状态的猎物利用了庇护所，但当捕食者处于不稳定状态时，久坐的人更多。总体而言，这项研究表明，捕食者群体的稳定性受到体型差异的调节，并可能影响猎物的反应。此外，它揭示了尽管减少了明显的社会冲突，但稳定人群中隐藏的新陈代谢成本仍然存在。