陷阱法调查转Bt棉对棉田地面蜘蛛群落的影响

Effects of transgenetic Bt cotton on ground-dwelling spider assemblages by pitfall traps

为明确转Bt棉对非靶标节肢动物棉田蜘蛛群落的影响,在棉花全生长期利用陷阱法对转Bt棉(中棉29)和传统棉田(湘杂3号)蜘蛛的群落多样性及数量动态变化进行了系统调查。结果表明:共采集棉田蜘蛛5 020头,隶属13科33种,其中转Bt棉田2 548头,隶属12科27种,传统棉田2 472头,隶属12科27种;转Bt棉田和传统棉田均以狼蛛科Lycosidae、平腹蛛科Gnaphosidae和隐石蛛科Titanoecidae为优势科,优势科的优势种也均为沟渠豹蛛Pardosa laura、蛞平腹蛛Gnaphosa kompirensis和白斑隐石蛛Nurscia albofasciata,2种棉田在地面蜘蛛群落组成上除少部分稀有物种存在差异外,优势科及优势科的优势种均无显著差异;且3种优势种蜘蛛数量、Shannon-Wiener多样性指数以及物种丰富度均无显著差异;2种棉田地面蜘蛛数量动态变化也无显著差异,均有2个高峰期,分别在苗期和铃期。表明转Bt棉对棉田地面蜘蛛群落无显著影响。

Several field studies have raised widespread concern that Bt plants can adversely affect nontarget insects. To address the effect of transgenic Bt cotton on ground-dwelling spider communities,the community structure of spiders in Bt cotton( Zhongmian 29) and non-Bt cotton( Xiangza 3) fields were investigated on Xingou farm in Jianghan Region,Wuhan,China,by using pitfall traps. In total,5 020 spiders representing 33 species among 13 families were captured. Remarkably,pitfall traps from both Bt and non-Bt cotton fields each captured 27 species representing 12 families from a total of 2 548 and 2 472 individuals,respectively. Families of Lycosidae,Gnaphosidae and Titanoecidae dominated the catches,along with Pardosa laura,Gnaphosa kompirensis,Nurscia albofasciat as the most dominant species captured in each family in the two fields,respectively. There were no significant differences in species composition between Bt and non-Bt cotton plots except some rare species. The results showed that the abundance of epigeic spiders,abundance of dominant species,species richness and Shannon-Wiener index were similar between Bt and non-Bt cottons. The epigeic spiders displayed population peaks in spring and summer in both treatments. Taken together,the transgenic Bt cotton tested in this study had no significant effects on epigeic spider community structure of the cotton fields.