Predation is a well‐studied driver of ecological selection on prey traits, which frequently drives divergence in anti‐predator performance across environments that vary in predation risk. However, predation also alters prey mortality regimes, where low predation risk often results in higher prey densities and consequently higher intensities of intraspecific resource competition. In addition, predation risk alters the foraging context, as acquiring food can be risky in the presence of predators. Thus, different predation regimes can drive divergent selection on traits associated with resource competition, such as foraging behaviours. Moreover, because sexes often differ in susceptibility to predation and limitations to their reproductive output, the intensity of the tradeoff between predator avoidance and resource competition may depend on sex. We used a laboratory experiment to assess key aspects of foraging performance in a predator‐free context in Bahamas mosquitofish Gambusia hubbsi wild‐caught from multiple populations that experience either high or low levels of predation risk. When competing for limited food resources at a common density, females from low‐predation regimes showed higher foraging and food consumption rates than females from high‐predation regimes. Males showed fewer differences between predation regimes, and an opposite pattern from females. We suggest these sex‐specific effects result from females facing a greater tradeoff between predation risk and resource competition, combined with males from high‐predation environments elevating foraging behaviours in the absence of nearby predators and females. Females of this species are larger than males, bear live young and show higher foraging rates in the wild than males. On the other hand, males spend more time pursuing females in the wild, and may exhibit greater flexibility in foraging behaviours based on the immediate context. Our results show that varying levels of predation risk can lead to differences in behaviours associated with resource competition, but these effects can strongly differ between sexes.

中文翻译：

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捕食方式的变化导致蚊鱼觅食行为的性别差异

捕食是对猎物性状进行生态选择的一个经过充分研究的驱动力，通常会导致在捕食风险各不相同的环境中，抗捕食者的性能出现差异。但是，捕食也会改变猎物的死亡率，在这种情况下，低捕食风险通常会导致更高的猎物密度，从而导致种内资源竞争的强度更高。此外，捕食风险会改变觅食环境，因为在存在掠食者的情况下获取食物可能会带来风险。因此，不同的捕食机制可以促使对与资源竞争相关的性状（例如觅食行为）进行不同的选择。此外，由于性别对捕食的敏感性和对生殖产量的限制常常不同，因此在避免捕食者与资源竞争之间权衡的强度可能取决于性别。盖布氏菌来自遭受高或低掠食风险水平的多个种群的野外捕获。当以共同的密度争夺有限的粮食资源时，来自低捕食制度的雌性的觅食和食物消耗率要高于来自高捕食制度的雌性。雄性在捕食方式之间的差异较小，而雌性则相反。我们建议这些性别特异性的影响是由于雌性面临捕食风险和资源竞争之间更大的权衡，再加上来自高捕食环境的雄性在没有附近捕食者和雌性的情况下提高了觅食行为。该物种的雌性比雄性大，活着年轻，在野外的觅食率高于雄性。另一方面，雄性花更多的时间在野外追捕雌性，并在基于即时上下文的觅食行为中表现出更大的灵活性。我们的结果表明，不同程度的掠夺风险可能导致与资源竞争相关的行为发生差异，但是这些影响在性别之间可能存在很大差异。