不同杀虫剂对大豆田节肢动物群落结构的影响

Effects of several insecticides on the arthropod community in soybean fields

通过田间调查明确了大豆田节肢动物群落构成及其优势种群,利用群落参数并结合笔者提出的群落扰动系数比较分析了马拉硫磷、阿维菌素、高效氯氰菊酯和敌敌畏等杀虫剂对大豆田节肢动物群落及其亚群落的影响,研究结果表明:不同杀虫剂对田间天敌、害虫和中性昆虫亚群的丰富度、多样性指数和均匀度指数影响存在较大差异,其中对中性昆虫亚群影响最大。4种杀虫剂中,阿维菌素对群落的影响最小;高效氯氰菊酯对群落的影响最大,大量杀伤了天敌并引起大豆蚜的再猖獗;不同杀虫剂作用下节肢动物群落恢复速度亦存在明显差异,其中阿维菌素防治田群落恢复速度较快,其它药剂防治田的群落恢复明显滞后或根本无法恢复。

The species composition of a soybean arthropod community was investigated. The effects of malathion, avermectins, β-eypermethrin and dichlorvos on the community and its sub-communities were compared using community characteristic parameters and a disturbance coefficient developed by ourselves. The results indicate that all insecticides tested had significant effects on species richness, Shannon＇ s index, homogeneity of sub-communities of natural enemies, insect pests and neutral insects. The sub-community of neutral insects underwent greater change than other sub- communities. Of the insecticides tested, avermectins had the least, and β-cypermethrin the most, effect on arthropod communities, the latter causing the greatest mortality among natural enemies and the resurgence of soybean aphids. There were significant differences in the recovery speed of arthropod communities treated with the four insecticides. In contrast to avermectins, the communities of plots treated with the other three insecticides either recovered more slowly or failed to recover during the period of the study.