Results of a 4-year plant survey and pitfall trapping in Bt maize and conventional maize fields regarding the occurrence of selected arthropod taxa

Abstract

In the Oderbruch region, Germany, an outbreak area of the European corn borer (Ostrinia nubilalis), we investigated the density and community composition of arthropods in Bacillus thuringiensis (Bt) and conventional (CV) maize fields from 2000 to 2003. Aphids, thrips, bugs and aphid predators on the plants were counted to obtain density estimates. Community structure of arthropod taxa on plants taken from field as well as ground-dwelling carabids caught in pitfall traps was investigated by ordination analysis. The density of most taxa varied considerably between the years. We detected a few significant differences between Bt and CV maize, but no specific tendencies. However, the ordination analyses revealed a small but significant influence of maize variety on the arthropod community. The percentage of total variance explained by maize variety was only 2.7% in ground dwellers and 2.1% in maize dwellers. The present data show that the influence of Bt maize on nontarget arthropods is small compared to field characteristics and yearly changing environmental conditions.