Animals may face trade-offs when several simultaneous functions or processes compete for limiting resources. In that context, allocation of resources to the most fitness-enhancing competing function can be prioritized. Immune response and locomotor performance are relevant fitness components, mainly due to their important roles as defence against pathogens and predators, respectively. However, both promote oxidative stress and consume energy and metabolites. Consistently, trade-offs between immune response and locomotion have been reported in some taxa. In this work, we examine whether an immune challenge hinders short-distance swimming speed of adult Iberian ribbed newts, Pleurodeles waltl. To that end, we inoculated Escherichia coli cell wall lipopolysaccharide (LPS), an innocuous antigen that triggers an immune response, in the sole pads of experimental newts, and phosphate buffer saline, with no physiological effect, in those of control newts. We estimated immune response as sole pad swelling and calculated swimming speed from videos of newts swimming towards a refuge nearby, 24 h and 7 days after inoculation. Sole pad swelling was greater in LPS-inoculated newts, but short-distance swimming speed was not affected by the immune challenge. These results could indicate priority allocation of resources to locomotion, which might be a consequence of compensatory mechanisms capable of avoiding locomotion impairment due to immune challenge. In any case, these findings could highlight the importance of short-distance escape as an antipredator strategy.

中文翻译：

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免疫挑战不会影响蝾螈的短距离逃逸速度

当多个同时进行的功能或过程竞争限制资源时，动物可能面临权衡取舍。在这种情况下，可以优先将资源分配给最能增强健康的竞争功能。免疫反应和运动性能是相关的健康组成部分，主要是由于它们分别作为防御病原体和捕食者的重要作用。然而，两者都会促进氧化应激并消耗能量和代谢物。一致地，在某些分类群中已经报道了免疫反应和运动之间的权衡。在这项工作中，我们检查免疫挑战是否会阻碍成年伊比利亚肋蝾螈 Pleurodeles waltl 的短距离游泳速度。为此，我们接种了大肠杆菌细胞壁脂多糖 (LPS)，这是一种触发免疫反应的无害抗原，在实验蝾螈的脚垫和磷酸盐缓冲盐水中，在对照蝾螈中没有生理影响。我们将免疫反应估计为鞋底肿胀，并根据蝾螈在接种后 24 小时和 7 天向附近避难所游泳的视频计算游泳速度。接种 LPS 的蝾螈的脚垫肿胀更大，但短距离游泳速度不受免疫攻击的影响。这些结果可能表明资源优先分配给运动，这可能是补偿机制能够避免由于免疫挑战引起的运动障碍的结果。无论如何，这些发现可以突出短距离逃生作为一种反捕食者策略的重要性。我们将免疫反应估计为鞋底肿胀，并根据蝾螈在接种后 24 小时和 7 天向附近避难所游泳的视频计算游泳速度。接种 LPS 的蝾螈的脚垫肿胀更大，但短距离游泳速度不受免疫攻击的影响。这些结果可能表明资源优先分配给运动，这可能是补偿机制能够避免由于免疫挑战引起的运动障碍的结果。无论如何，这些发现可以突出短距离逃生作为一种反捕食者策略的重要性。我们将免疫反应估计为鞋底肿胀，并根据蝾螈在接种后 24 小时和 7 天向附近避难所游泳的视频计算游泳速度。接种 LPS 的蝾螈的脚垫肿胀更大，但短距离游泳速度不受免疫攻击的影响。这些结果可能表明资源优先分配给运动，这可能是补偿机制能够避免由于免疫挑战引起的运动障碍的结果。无论如何，这些发现可以突出短距离逃生作为一种反捕食者策略的重要性。但短距离游泳速度不受免疫挑战的影响。这些结果可能表明资源优先分配给运动，这可能是补偿机制能够避免由于免疫挑战引起的运动障碍的结果。无论如何，这些发现可以突出短距离逃生作为一种反捕食者策略的重要性。但短距离游泳速度不受免疫挑战的影响。这些结果可能表明资源优先分配给运动，这可能是补偿机制能够避免由于免疫挑战引起的运动障碍的结果。无论如何，这些发现可以突出短距离逃生作为一种反捕食者策略的重要性。