Diversity of insects under the effect of Bt maize and insecticides

ABSTRACT: The genetically modified maize to control some caterpillars has been widely used in Brazil. The effect of Bt maize and insecticides was evaluated on the diversity of insects (species richness and abundance), based on the insect community, functional groups and species. This study was conducted in genetically modified maize MON810, which expresses the Cry1Ab protein from Bacillus thuringiensis Berliner, and conventional maize with and without insecticide sprays (lufenuron and lambda-cyhalothrin) under field conditions in Ponta Grossa (Paraná state, Brazil). Insect samplings were performed by using pitfall trap, water tray trap and yellow sticky card. A total of 253,454 insects were collected, distributed among nine orders, 82 families and 241 species. No differences were observed in the insect community based on the richness, diversity and evenness indices. Predators and pollinators were more abundant in genetically modified maize. Parasitoids, detritivores, sap-sucking herbivores and chewing herbivores were more abundant in conventional maize with insecticide sprays. Significant differences were found for the species Colopterus sp., Colaspis occidentalis (L.) and Nusalala tessellata (Gerstaecker) which were most abundant in Bt maize, and Dalbulus maidis and Condylostylus sp.2 in conventional maize.

摘要：用于防治部分鳞翅目幼虫的转基因玉米已在巴西广泛推广应用。本研究基于昆虫群落、功能类群及物种层面，评估了转Bt基因玉米（Bt maize）与杀虫剂对昆虫多样性（物种丰富度与个体丰度）的影响。试验于巴西巴拉那州蓬塔格罗萨的田间开展，供试材料包括表达苏云金芽胞杆菌（Bacillus thuringiensis Berliner）Cry1Ab蛋白的转基因玉米MON810，以及喷施/不喷施杀虫剂（氟虫脲lufenuron与氯氟氰菊酯lambda-cyhalothrin）的常规玉米。昆虫样本采集采用陷阱诱捕法、水盆诱捕法与黄色粘虫板法，共采集到昆虫253454头，隶属于9个目、82个科、241个物种。基于物种丰富度、多样性与均匀度指数分析，各处理间昆虫群落无显著差异。转基因玉米田中捕食性昆虫与传粉昆虫的丰度更高；喷施杀虫剂的常规玉米田中寄生性昆虫、腐食性昆虫、刺吸式植食昆虫与咀嚼式植食昆虫的丰度更高。研究发现部分物种的丰度存在显著差异：扁谷盗属未定种（Colopterus sp.）、西方叶甲（Colaspis occidentalis (L.)）与格氏斑草蛉（Nusalala tessellata (Gerstaecker)）在转Bt基因玉米田中丰度更高；而玉米矮花叶叶蝉（Dalbulus maidis）与长足虻属未定种2（Condylostylus sp.2）在常规玉米田中丰度更高。