Animals are expected to choose foods that optimize their growth, reproduction and survival, but their dietary choice changes when suffering stress. Here, we provide the first report of nematode stress resulting from exposure to earthworm-produced cyclic peptides, and confirm that this stress changes the dietary choice of the model animal Caenorhabditis elegans and other soil-dwelling bacterial-feeding nematodes. When allowed free choice in a stress-free environment, nematodes prefer feeding on high-quality bacteria to support a higher reproduction and a shorter lifespan, supporting a reproduction-dominated energy allocation pattern. However, they feed less on preferred food (high-quality bacteria) and include more unpreferred food (low-quality bacteria) in the diet when stressed by the toxic cyclic peptides. Nematodes that eat more unpreferred bacteria appear to shift towards a survival-dominated energy allocation pattern. Specifically, limited resources obtained from low-quality bacteria are preferentially allocated to repair cyclic peptide-induced damage of their DNA and complete their lifespan, although at significantly reduced reproduction level. Our results demonstrate that nematodes can actively change their dietary strategy to maintain survival at the cost of reproduction when they experience acute stress. This stress-driven adjustment of dietary choice may be the key to understand feeding ecology and food web structure.

动物应该选择能优化其生长、繁殖和生存的食物，但在承受压力时，它们的饮食选择会发生变化。在这里，我们提供了由于暴露于蚯蚓产生的环肽而导致的线虫应激的第一份报告，并确认这种应激改变了模型动物秀丽隐杆线虫的饮食选择和其他居住在土壤中的以细菌为食的线虫。当允许在无压力环境中自由选择时，线虫更喜欢以优质细菌为食，以支持更高的繁殖率和更短的寿命，从而支持以繁殖为主导的能量分配模式。然而，当受到有毒环肽的压力时，它们会减少偏好的食物（优质细菌），并在饮食中加入更多的非偏好食物（低质量细菌）。吃更多非首选细菌的线虫似乎转向以生存为主导的能量分配模式。具体而言，从低质量细菌获得的有限资源优先用于修复环肽诱导的 DNA 损伤并完成其寿命，尽管繁殖水平显着降低。我们的研究结果表明，线虫在遇到急性压力时可以积极改变它们的饮食策略，以牺牲繁殖为代价来维持生存。这种压力驱动的饮食选择调整可能是了解喂养生态和食物网结构的关键。