Storer Nicholas P, Peck Steven L, Gould Fred, Van Duyn John W, Kennedy George G
Department of Entomology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695-7613, USA.
J Econ Entomol. 2003 Feb;96(1):156-72. doi: 10.1093/jee/96.1.156.
A simulation model is developed to examine the role of spatial processes in the evolution of resistance in Helicoverpa zea populations to Bt corn and Bt cotton. The model is developed from the stochastic spatially explicit Heliothis virescens model described by Peck et al. (1999), to accommodate a spatial mix of two host crops (corn and cotton), and to reflect the agronomic practices, as well as the spatial and temporal population dynamics of H. zea, in eastern North Carolina. The model suggests that selection for resistance is more intense in Bt cotton fields than in Bt corn fields. It further suggests that local gene frequencies are highly dependent on local deployment levels of Bt crops despite the high mobility of the adult insects. Region-wide average gene frequencies depend on the region-wide level of Bt deployment, so incomplete technology adoption slows the rate of resistance evolution. However, on a local scale, H. zea populations in clusters of fields in which Bt use is high undergo far more rapid evolution than populations in neighboring clusters of fields in which Bt use is low. The model suggests that farm-level refuge requirements are important for managing the risk of resistance. The model can be used as an aid in designing plans for monitoring for resistance by suggesting the appropriate distribution of monitoring locations, which should focus on areas of highest Bt crop deployment. The findings need to be placed in the context of the input parameters, many of which are uncertain or highly variable in nature, and therefore, a thorough sensitivity analysis is warranted.
开发了一个模拟模型，以研究空间过程在棉铃虫种群对Bt玉米和Bt棉花抗性进化中的作用。该模型是在Peck等人（1999年）描述的随机空间明确的烟芽夜蛾模型基础上开发的，以适应两种寄主作物（玉米和棉花）的空间混合，并反映北卡罗来纳州东部的农艺实践以及棉铃虫的时空种群动态。该模型表明，Bt棉田对抗性的选择比Bt玉米田更强烈。它还表明，尽管成虫具有高迁移性，但局部基因频率高度依赖于Bt作物局部的种植水平。全区域平均基因频率取决于全区域Bt作物的种植水平，因此，技术采用不完全会减缓抗性进化的速度。然而，在局部尺度上，Bt作物使用率高的田块集群中的棉铃虫种群比Bt作物使用率低的相邻田块集群中的种群进化速度要快得多。该模型表明，农场层面的避难所要求对于管理抗性风险很重要。该模型可通过建议监测地点的适当分布来辅助设计抗性监测计划，监测地点应集中在Bt作物种植最多的区域。研究结果需要结合输入参数来考量，其中许多参数本质上是不确定的或高度可变的，因此，有必要进行全面的敏感性分析。
