Abstract Our understanding on how organisms evolutionarily cope with simultaneously occurring, multiple threats over generations is still elusive. In a long‐term experimental study, we therefore exposed clones of a freshwater cladoceran, Daphnia magna, to threats from predation and ultraviolet radiation (UVR) during three consecutive parthenogenetic generations. We show that Daphnia can adapt to different sets of threats within three generations through modifying morphology, swimming behavior, or life‐history traits. When faced with predator cues, D. magna responded with reduced body size, whereas exposure to UVR induced behavioral tolerance when again exposed to this threat. Such UVR‐tolerant behavior was initially associated with a reduced clutch size, but Daphnia restored the reproductive output gradually through generations. The findings advance our understanding on how those common invertebrates, with a global distribution, are able to persist and rapidly become successful in a changing environment.

中文翻译：

---

对浮游动物世代威胁的不同反应

摘要 我们对生物体如何进化应对同时发生的、世代相传的多重威胁的理解仍然难以捉摸。因此，在一项长期的实验研究中，我们将淡水枝角类动物 Daphnia magna 的克隆暴露在连续三代孤雌生殖期间受到捕食和紫外线辐射 (UVR) 的威胁。我们表明，水蚤可以通过改变形态、游泳行为或生活史特征来适应三代内不同的威胁。当面对捕食者的线索时，D. magna 的反应是减小体型，而当再次暴露于这种威胁时，暴露于 UVR 会引起行为耐受性。这种耐受紫外线的行为最初与离合器大小的减少有关，但水蚤通过几代人逐渐恢复了繁殖能力。