Department of Mathematics, Faculty of science, University of Tabuk, Tabuk, 71491, Saudi Arabia.
School of Computing and Mathematical Sciences, University of Leicester, Leicester, LE1 7RH, UK.
Sci Rep. 2022 Sep 2;12(1):15023. doi: 10.1038/s41598-022-18120-z.
A major goal of biological control is the reduction and/or eradication of pests using various natural enemies, in particular, via deliberate infection of the target species by parasites. To enhance the biological control, a promising strategy seems to implement a multi-enemy assemblage rather than a single control agent. Although a large body of theoretical studies exists on co-infections in epidemiology and ecology, there is still a big gap in modelling outcomes of multi-enemy biological control. Here we theoretically investigate how the efficiency of biological control of a pest depends on the number of natural enemies used. We implement a combination of eco-epidemiological modelling and the Adaptive Dynamics game theory framework. We found that a progressive addition of parasite species increases the evolutionarily stable virulence of each parasite, and thus enhances the mortality of the target pest. However, using multiple enemies may have only a marginal effect on the success of biological control, or can even be counter-productive when the number of enemies is excessive. We found the possibility of evolutionary suicide, where one or several parasite species go extinct over the course of evolution. Finally, we demonstrate an interesting scenario of coexistence of multiple parasites at the edge of extinction.
生物防治的一个主要目标是利用各种天敌（特别是通过故意感染目标物种的寄生虫）来减少和/或消灭害虫。为了增强生物防治的效果，一种有前途的策略似乎是采用多种天敌的组合，而不是单一的控制剂。尽管在流行病学和生态学中已经有大量关于共感染的理论研究，但在多敌生物防治的模型结果方面仍存在很大差距。在这里，我们从理论上研究了生物防治害虫的效率如何取决于使用的天敌数量。我们实施了生态流行病学模型和适应性动态博弈论框架的组合。我们发现，寄生虫物种的逐渐增加会增加每种寄生虫的进化稳定毒力，从而提高目标害虫的死亡率。然而，当使用多种天敌时，对生物防治的成功可能只有边际效应，或者当天敌数量过多时甚至可能适得其反。我们发现了进化自杀的可能性，即一种或几种寄生虫物种在进化过程中灭绝。最后，我们展示了一个有趣的场景，即在灭绝的边缘共存多种寄生虫。
