In many terrestrial, marine, and freshwater predator-prey communities, young predators can be vulnerable to attacks by large prey. Frequent prey counter-attacks may hinder the persistence of predators. Despite the commonness of such role reversals in nature, they have rarely been addressed in evolutionary modelling. To understand how role reversals affect ecological and evolutionary dynamics of a predator-prey community, we derived an ecological model from individual-level processes using ordinary differential equations. The model reveals complex ecological dynamics, with possible bistability between alternative coexistence states and an Allee effect for the predators. We find that when prey counter-attacks are frequent, cannibalism is necessary for predator persistence. Using numerical analysis, we also find that a sudden ecological shift from coexistence to predator extinction can occur through several catastrophic bifurcations, including ‘saddle-node’, ‘homoclinic’, and ‘subcritical Hopf’. The analysis of single-species evolution reveals that predator selection towards increasing or decreasing cannibalism triggers a catastrophic shift towards an extinction state of the predators. Such an evolutionary extinction of the predators may also be caused by prey selection towards increasing foraging activity because it facilitates encounters with vulnerable, young predators. The analysis of predator-prey coevolution further demonstrates that predator’s catastrophic extinction becomes an even more likely outcome than in single-species evolution. Our results suggest that when young predators are vulnerable to prey attacks, a sudden extinction of the predators may be more common than currently understood.

在许多陆地，海洋和淡水捕食者-猎物社区中，年轻的捕食者可能容易受到大型猎物的攻击。频繁的猎物反击可能会阻碍捕食者的持久性。尽管这种角色互换在自然界中很普遍，但在进化建模中很少涉及到它们。为了了解角色逆转如何影响捕食者－猎物社区的生态和进化动力学，我们使用常微分方程从个体层次的过程中得出了生态模型。该模型揭示了复杂的生态动力学，在交替共存状态和掠食者的Allee效应之间可能存在双稳态。我们发现，当猎物反击频繁发生时，食人族对于保持捕食者的生存是必要的。使用数值分析 我们还发现，可能通过几种灾难性的分叉发生突然的从共存到捕食者灭绝的生态转变，包括“鞍结”，“同系”和“亚临界霍普夫”。对单物种进化的分析表明，捕食者向食人族增加或减少的选择引发了向捕食者灭绝状态的灾难性转变。捕食者的这种进化性灭绝也可能是由于捕食者选择增加觅食活动而引起的，因为它促进了与脆弱的年轻捕食者的相遇。对捕食者-猎物共进化的分析进一步表明，与单物种进化相比，捕食者的灾难性灭绝成为更有可能的结果。我们的结果表明，当年幼的捕食者容易受到猎物攻击时，