定量评价天敌昆虫控害功能的稳定同位素方法

Quantitative evaluation of the biological control efficiency of predatory insects based on stable isotope analyses

天敌在区域性多作物农田景观系统中辗转捕食害虫,对调节和控制害虫种群数量发挥着非常重要的作用。明确天敌昆虫的食物来源和扩散规律是定量评价其控害功能的重要环节。其中,稳定同位素标记方法是追溯生物个体的食物来源和探究其运动规律的重要手段。本文首先介绍该标记方法的基本原理,接着以天敌昆虫龟纹瓢虫Propylea japonica(Thunberg)为例,应用稳定同位素碳标记方法追溯其在棉花和玉米农田景观系统中取食来源与食物比例;最后叙述了稳定同位素方法的应用前景和存在的问题。

Predatory insects play important roles in regulating and controlling pest insect populations in the agricultural landscape system. Tracing the diet and movements of natural enemies are basic steps for quantitatively evaluating the effectiveness of these species as biological control agents. Stable isotope analyses can be used to determine insects＇ dietary sources and movements. In this study, we first introduce the fundamental principles of stable isotope analyses. We then use this technique to determine the prey origins and proportions of the predatory beetle, Propylea japonica （Thunberg）, in an agricultural landscape system comprised of cotton and maize crops. Finally, we discuss the potential and caveats of this method.