转Bt基因抗虫棉田昆虫群落结构的研究

不同类型棉田对比调查分析结果可看出 ,非抗虫棉田比转Bt基因抗虫棉田昆虫群落物种数减少 ,两类棉田昆虫群落中 ,棉蚜、棉蓟马、棉叶螨相对多度较大 ,在食叶蛀桃类害虫中 ,以棉铃虫的个体数量占优势 ,美洲斑潜蝇的个体数量在两类棉田中呈明显上升趋势。两类棉田比较分析主要害虫棉铃虫、棉蚜、棉叶螨的类群相对多度 ,转Bt基因抗虫棉田比非抗虫棉田减少 ,而棉蓟马、棉叶蝉、白飞虱、棉盲蝽类群相对多度增大 ,天敌类群相对多度较大。不同类型棉田昆虫群落结构特征分析结果表明 ,由于棉田施用农药多少不同 ,非抗虫棉田比转Bt基因抗虫棉田物种丰富度有不同程度的减少 ,两类棉田害虫优势度和优势种不完全相同 ,昆虫总群落、害虫亚群落和天敌亚群落多样性指数在时间序列上受外界环境条件影响较大 ,总的表现是转Bt基因抗虫棉田昆虫群落变化较规律 ,多样性指数偏高

Study on structure of insect community in Bt transgenic cotton field

The insect specie quantities in two types of cotton fields were investigated and analyzed The result showed that insect specie quantity in common cotton field(non-Bt cotton) is less than that in Bt transgenic cotton field In terms of insect community of two types of fields, the relative abundances of Aphis gossypii, Thrips tabaci and two spotted spider mite are larger Among leaf eating and bollworm pest, bollworm quantity is dominant and Liriomyza sativae quantity is obviously rising In Bt transgenic cotton field, the relative abundances of bollworm, Aphis gossypii and two spotted spider mite are less than those in common field, but those of Thrips tabaci, cotton leaf hoyper, Bemisia tabaci and cotton plant bug are rising, that of natural enemy is larger Analysis on structure characteristics of insect community in two types of cotton fields showed that owing to the difference of pesticide application rate, the species richness in Bt transgenic field has decreased in some degree comparing with that in common field, the dominance and ecological concentration are not entirely same in two fields The diversity indexes of total insect community, pest subcommunity and natural enemy subcommunity change greatly with circumcetance, the change of insect community appears regular and the diversity index is higher in Bt transgenic cotton field