PDF(Pubmed)
Abstract：
The interplay of host-parasite and predator-prey interactions is critical in ecological dynamics because both predators and parasites can regulate communities. But what is the prevalence of infected prey and predators when a parasite is transmitted through trophic interactions considering stochastic demographic changes? Here, we modelled and analysed a complex predator-prey-parasite system, where parasites are transmitted from prey to predators. We varied parasite virulence and infection probabilities to investigate how those evolutionary factors determine species\' coexistence and populations\' composition. Our results show that parasite species go extinct when the infection probabilities of either host are small and that success in infecting the final host is more critical for the survival of the parasite. While our stochastic simulations are consistent with deterministic predictions, stochasticity plays an important role in the border regions between coexistence and extinction. As expected, the proportion of infected individuals increases with the infection probabilities. Interestingly, the relative abundances of infected and uninfected individuals can have opposite orders in the intermediate and final host populations. This counterintuitive observation shows that the interplay of direct and indirect parasite effects is a common driver of the prevalence of infection in a complex system.
摘要：
宿主-寄生虫和捕食者-猎物相互作用的相互作用在生态动力学中至关重要，因为捕食者和寄生虫都可以调节群落。但是，当寄生虫通过考虑随机人口变化的营养相互作用传播时，受感染的猎物和捕食者的患病率是多少？这里，我们建模并分析了一个复杂的捕食者-猎物-寄生虫系统，寄生虫从猎物传播到捕食者。我们改变了寄生虫的毒力和感染概率，以研究这些进化因素如何决定物种“共存和种群”的组成。我们的结果表明，当任一宿主的感染概率较小时，寄生虫物种就会灭绝，成功感染最终宿主对于寄生虫的生存更为重要。虽然我们的随机模拟与确定性预测一致，随机性在共存和灭绝之间的边界区域中起着重要作用。不出所料,感染者的比例随着感染概率的增加而增加。有趣的是,感染和未感染个体的相对丰度在中间和最终宿主群体中可以具有相反的顺序。这种违反直觉的观察表明，直接和间接寄生虫效应的相互作用是复杂系统中感染流行的共同驱动因素。
