This study aimed to verify the difference between flower-visiting insect communities in genetically modified cotton (Bt) and conventional cotton (non-Bt). The study was conducted in a commercial cotton field in the municipality of Maracaju, Mato Grosso do Sul, Brazil. The collections of flower visitors were performed every 3 days in the morning during the reproductive period of cotton and employed 2 treatments: Bt cotton and non-Bt cotton. By the end of flowering, 1,310 specimens were collected, 56.56% on Bt cotton flowers and 43.44% on non-Bt cotton flowers. Even though the abundance of collected insects on Bt cotton was higher, species richness in non-Bt was higher than Bt, with a diversity of 73 species on Bt cotton and 84 species on non-Bt. Species richness of flower visitors varied between sampling times for both treatments and between the days of flowering, therefore, the species richness was lower at the beginning and the end of flowering in both cotton cultivars. But the species richness did not vary between cultivars of cotton. Species composition of insects was different during the periods of flower visitation, between cotton cultivars as well as between the interaction of these two factors. There was also a variation between the days of flowering but not between days and cotton cultivars. Based on this study, it was concluded that there are differences between the species of insects that visit flowers of Bt cotton and non-Bt cotton.
Cotton; risk assessment; Bacillus thuringiensis; genetically modified plants