One of the options to reduce predation risk is reallocation of energy into locomotion system. The higher aerobic capacity, the more energy can be partitioned into an escape. Thus, increase in aerobic capacity can increase prey escape abilities. We investigated prey (freshwater crustaceans: Dikerogammarus villosus and Gammarus jazdzewskii) ability to improve their locomotor performance through an increase in aerobic capacity under chronic predation risk. We forced gammarids (pre-exposed to the predation cue or control) to long-distance swimming in the presence or absence of predation cues to obtain: control (pre-exposure and test in control conditions), acute (pre-exposure to control conditions, test in the presence of the predation cue) and chronic (pre-exposure and test in the presence of the cue) risk treatments. After this forced swimming effort, we measured various swimming parameters, glycogen content, and lactate concentration of the experimental amphipods. Exposure to predation cues made G. jazdzewskii reduce its speed after prolonged forced swimming in the presence of predation cues, whereas D. villosus never changed its swimming performance due to predation risk. In both species, post-effort lactate concentration was higher under the acute predation risk than in risk-free conditions. However, only D. villosus demonstrated lower lactate concentration when exposed to chronic vs. acute predation risk. Moreover, pre-exposure of both species to predation cues caused reduction in glycogen content. We showed that under chronic predation risk some prey species can modify their physiology to increase aerobic capacity and sustain high efficiency of escape performance. However, this phenomenon is species-specific and costly.

中文翻译：

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慢性捕食风险通过行为和生理变化影响猎物逃生能力

降低捕食风险的选择之一是将能量重新分配到运动系统中。有氧能力越高，越多的能量可以分配到逃逸中。因此，有氧能力的增加可以增加猎物的逃生能力。我们调查了猎物（淡水甲壳类动物：Dikerogammarus villosus 和 Gammarus jazdzewskii）通过在慢性捕食风险下增加有氧能力来改善其运动性能的能力。我们强迫 gammarids（预暴露于捕食线索或控制）在存在或不存在捕食线索的情况下进行长距离游泳以获得：控制（预暴露和控制条件下的测试），急性（预暴露于控制条件，在存在捕食线索的情况下进行测试）和慢性（在存在线索的情况下进行预暴露和测试）风险治疗。在这种强迫游泳努力之后，我们测量了实验片脚类动物的各种游泳参数、糖原含量和乳酸浓度。暴露于捕食线索会使 G. jazdzewskii 在存在捕食线索的情况下长时间强迫游泳后降低其速度，而 D. villosus 由于捕食风险而从未改变其游泳性能。在这两个物种中，急性捕食风险下的努力后乳酸浓度高于无风险条件下。然而，只有 D. villusus 在暴露于慢性和急性捕食风险时表现出较低的乳酸浓度。此外，两种物种预先暴露于捕食线索会导致糖原含量减少。我们表明，在慢性捕食风险下，一些猎物可以改变其生理机能以增加有氧能力并维持高效的逃生性能。然而，这种现象是特定于物种的且成本高昂。