Matsuoka Tsutomu, Seno Hiromi
Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
J Theor Biol. 2008 May 7;252(1):87-97. doi: 10.1016/j.jtbi.2008.01.024. Epub 2008 Feb 5.
We analyze a time-discrete mathematical model of host-parasite population dynamics with harvesting, in which the host can be regarded as a pest. We harvest a portion of the host population at a moment in each parasitism season. The principal target of the harvesting is the host; however, the parasite population may also be affected and reduced by a portion. Our model involves the Beverton-Holt type density effect on the host population. We investigate the condition in which the harvesting of the host results in an eventual increase of its equilibrium population size, analytically proving that the paradoxical increase could occur even when the harvesting does not directly affect the parasite population at all. We show that the paradox of pest control could be caused essentially by the interspecific relationship and the intraspecific density effect.
我们分析了一个带有收获项的宿主 - 寄生虫种群动态的时间离散数学模型，其中宿主可被视为害虫。在每个寄生季节的某一时刻，我们收获一部分宿主种群。收获的主要目标是宿主；然而，寄生虫种群也可能受到一定影响并减少一部分。我们的模型涉及对宿主种群的贝弗顿 - 霍尔特型密度效应。我们研究宿主收获导致其平衡种群规模最终增加的条件，通过分析证明，即使收获根本不直接影响寄生虫种群，也可能出现这种似非而是的增长。我们表明，害虫控制的悖论本质上可能是由种间关系和种内密度效应引起的。
