Singh Abhyudai, Nisbet Roger M
Department of Electrical and Computer Engineering, University of California at Santa Barbara, CA 93106-9610, USA.
J Theor Biol. 2007 Aug 21;247(4):733-42. doi: 10.1016/j.jtbi.2007.04.004. Epub 2007 Apr 10.
Arthropod host-parasitoid interactions constitute a very important class of consumer resource dynamics. Discrete-time models are a tradition for such interactions and are characterized by an updating function, which relates the population densities at a fixed date in one year to those at the same date in the previous year. Previous workers have investigated the effects of functional response and density dependence on the stability of the host-parasitoid interaction by heuristically incorporating them in the updating function. Such an approach ignores the effects of population changing continuously within a year due to different processes (for example intraspecific competition, mortality from parasitism) that may act simultaneously. Their cumulative effect on the updating function is not obvious and a more systematic methodology is needed. This paper uses a hybrid approach to formulate the updating function. This is done by modeling the dynamics of various within-year processes in continuous-time, and reproduction as a discrete event. Using this formalism we derive results connecting the stability of the host-parasitoid interaction with different forms of density dependence and the form of the functional response. The latter results contradict previous conclusions from heuristically formulated models, and illustrate the need for such a hybrid approach in discrete-time host-parasitoid theory.
节肢动物宿主 - 寄生蜂的相互作用构成了一类非常重要的消费者 - 资源动态关系。离散时间模型是此类相互作用的传统模型，其特点是具有一个更新函数，该函数将一年中固定日期的种群密度与上一年同一日期的种群密度联系起来。先前的研究人员通过在更新函数中启发式地纳入功能反应和密度依赖性，研究了它们对宿主 - 寄生蜂相互作用稳定性的影响。这种方法忽略了由于不同过程（例如种内竞争、寄生导致的死亡率）可能同时起作用而使种群在一年内持续变化的影响。它们对更新函数的累积影响并不明显，因此需要一种更系统的方法。本文采用混合方法来构建更新函数。这是通过对连续时间内各种年内过程的动态进行建模，并将繁殖视为离散事件来实现的。使用这种形式体系，我们得出了将宿主 - 寄生蜂相互作用的稳定性与不同形式的密度依赖性以及功能反应的形式联系起来的结果。后一个结果与启发式构建模型得出的先前结论相矛盾，并说明了在离散时间宿主 - 寄生蜂理论中采用这种混合方法的必要性。
