The coexistence of competing parasites. Part II - Hyperparasitism and food chain dynamics
The coexistence of competing parasites. Part II - Hyperparasitism and food chain dynamics
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DOI：
10.1006/jtbi.1998.0717
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发表时间：
1998-08-07
影响因子：
2
通讯作者：
Hochberg, ME
中科院分区：
文献类型：
--
作者：
Holt, RD;Hochberg, ME
重寄生是一种广泛存在于自然群落中的相互作用，但迄今为止在理论文献中很少受到关注。在这篇文章中，我们比较了食物链(资源-猎物-捕食者系统)和宿主-寄生虫-重寄生虫相互作用的规范模型。我们关注微寄生虫，所以动力学变量是不同类别的宿主个体的丰度(例如，有或没有特定的寄生虫)，并假设寄生虫是调节宿主种群的唯一因素。对寄主控制的模型的分析表明，寄主种群的内在增长率r是控制寄主种群持久性的一个基本参数。然后，我们研究了一个模型，在该模型中，重寄生虫可以影响宿主的出生、死亡和从主要寄生虫中恢复的速度。有很多种结果是可能的。例如，重寄生虫可以稳定固有的不稳定的宿主-寄生虫系统，或者破坏稳定的系统。在稳定平衡时的持久性通常要求宿主的内在增长率r在限定的范围内；在低r时，重寄生虫可能不能持久(在稳定的系统中)，而在高r时，系统不稳定，宿主种群以无界的方式增长。最后，我们为未来的工作勾画了方向，并对我们的结果提出了一些可能的实际意义。(C)1998年学术出版社。
Hyperparasitism is a widespread interaction in natural communities, but has to date received little attention in the theoretical literature. In this paper, we compare canonical models for food chains (resource-prey-predator systems) and host-parasite-hyperparasite interactions. We focus on microparasites, so the dynamical variables are the abundances of host individuals in different classes (e.g. with or without a particular parasite), and assume that the parasite is the only factor regulating a host population. Analysis of a "donor-controlled" model in which the primary parasite regulates host population growth, but with no additional demographic impact of the hyperparasite, suggests that intrinsic growth rate r of the host population is a fundamental parameter governing persistence of the hyperparasite. We then examine a model in which the hyperparasite can affect host births, deaths, and rate of recovery from the primary parasite. A wide range of outcomes are possible. For instance, hyperparasites can stabilize inherently unstable host-parasite systems, or destabilize stable systems. Persistence at a stable equilibrium often requires that the host intrinsic growth rate r lie within defined bounds; at low r, the hyperparasite may not be able to persist (in stable systems), whereas at high r the system is unstable and the host population grows in an unbounded fashion. We conclude by sketching directions for future work, and suggesting some possible practical implications of our results. (C) 1998 Academic Press.