基于生命表参数的棉铃虫种群动态模拟研究

Stochastic simulation of cotton bollworm population dynamics based on life-table parameters

依据对棉铃虫自然种群生命表研究所获得的种群统计参数,采用蒙特卡罗方法,模拟了随机环境条件下的棉铃虫种群发生动态。模拟结果显示,同一输入参数(模拟的1代残虫量),经过确定世代或生活史阶段后,棉铃虫的种群密度既可能为轻发生,也可能种群暴发。环境条件有利时,输入变量(模拟的1代残虫量)影响棉铃虫最大可能的发生程度。当棉铃虫为中等或轻发生时,1代残虫量(模型输入参数)和最终的棉铃虫发生程度(模型输出)没有明显的依赖关系。相同的最终棉铃虫发生程度所对应的模型的输入变量可以有多种水平。模拟结果显示,在环境条件比较有利情况下,棉铃虫只需要1个世代或某一个生活史阶段(如蛹期),种群密度即可达暴发水平。本文的研究结果说明,对棉铃虫中长期发生态势的预测,存在一定程度的不确定性。

Based on the demographic parameters of life table of the cotton bollworm, Helicoverpa armigera （Htibner）, its population dynamics was simulated using Markov chain Monte Carlo method. The simulation results showed that cotton bollworm population dynamics was very complicated. Although original survived larvae were same, after several generations or life history stages, the population density of cotton bollworm varied enormously, ranging from slight occurrence to outbreak. Only if the environment was very favorable for cotton bollworm, did the inputted parameter, the survived larvae of first generation, affect the pest＇ s probable maximum occurrence degree. When the occurrence degree was slight or moderate, the original survived larvae and the final population density of cotton bollworm had no significant relationship. However, if environmental conditions were favorable to the bollworm for one generation or even a life history stage, cotton bollworm would break out. The simulated results suggest that uncertainty exists in some extent to make longterm forecast of the bollworm dynamics.