Diversity, Abundance, and Effect of Genetically Modified Maize on Nontarget Predators in Sinaloa, Mexico

Maize (Zea mays L.) that has been genetically modified (GM) with the insertion of Bacillus thuringiensis Berliner (Bt) genes for pest control has become a useful tool in modern agriculture. In Mexico, planting of GM maize is not approved; however, field tests focused on the biotechnological efficacy of GM maize in controlling pests and the effects on nontarget organisms were authorized and conducted from 2009 to 2013. In Sinaloa, Mexico, plantings of the Bt corn hybrids Agrisure™ 3000 GT, Agrisure® Viptera™ 3110, and Agrisure® Viptera™ 3111, along with their respective isolines without the Bt toxin, were compared for their impact on nontarget predators. An additional treatment with conventional insecticide also was included in the comparisons. Predator abundance, diversity, richness, and uniformity of diversity were estimated by sampling populations with yellow sticky traps, pitfall traps, and a standard insect sweep net. A total of 17,626 predators, representing nine taxonomic orders and 30 families, were collected over all treatments in the different localities. Although predator abundance was slightly higher on the GM hybrids than in non-GM lines, the differences were not statistically significant. Our results from these studies in Sinaloa, Mexico, conclude that GM maize expressing the Bt toxin had no adverse effect on the population density of nontarget predators.