Species Richness and Community Composition of Ants and Beetles in Bt and non-Bt Maize Fields

Abstract

Insect-resistant genetically modified (GM) plants have been cultivated in several countries on a large scale. These plants express the Cry toxins from the bacterium Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt), which confers target-pest resistance to plants. Studies on the effects of GM plants on nontarget organisms are important to assess the technology’s impact on biodiversity. The objective of this study was to determine whether there are differences in the species richness and composition of ants and ground beetles in Bt maize (four different toxins: Cry1Ab, Cry1F, and Cry1A.105/Cry2Ab2) and conventional isoline (non-Bt) fields, in the first (summer) and second (winter) cropping seasons in 13 localities of Mato Grosso do Sul State, Brazil, over a 2-yr period (2009–2011). The assessment of Coleoptera and Formicidae species was performed using pitfall traps placed in fields throughout the period of vegetative growth and maturation of plants. Data were analyzed using faunistic indices of species richness, ordination by nonmetric multidimensional scaling, and multivariate analysis of variance. No statistically significant difference was found in the species richness of ant and ground beetle communities when comparing sites of Bt with those of non-Bt maize. Overall, Bt technology did not affect the composition of ant and ground beetles; however, municipality and cropping season exerted influence on the beetle composition. Some species were only observed in the first crop, whereas others were only observed in the second crop. This research suggests that Bt maize does not affect ant and ground beetle populations differently from its isoline.

Field efficacy of Bt cotton containing events DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 against lepidopteran pests and impact on the non-target arthropod community in Brazil

“…At Montividiu, when about 50% of cotton bolls attained their final size (GS7: 75 stage), ground-dwelling carabids, ants and orthopteran nymphs collected by pitfall trapping were more abundant in non- Bt cotton, compared with Bt cotton expressing Bt events DAS-21023-5 × DAS-24236-5 × SYN-IR102-7. Contrary to these results, Bt maize expressing different toxins Cry1Ab, Cry1F, Cry1A.105 and Cry2Ab2 did not affect the composition of ants and ground beetles [ 82 ]. At Indianópolis and Montividiu, sticky card monitoring showed similarities in NTA abundance and composition during the sampled periods, with observation of statistically significant differences in abundance only for some groups.…”

Management of target pests of Bt soybean in refuge areas, assessment of ecological risk to ground-dwelling predators and their implications for insect resistance the management

“…For this, the use of high-dose concept of GM plants expressing a high concentration of the insecticidal Bt toxins combined with refuge plantings (non-Bt plants) pests (Cividanes et al, 2018;Martins et al, 2018). In relation to the ants, besides being generalist predators and contributing to natural pest mortality, they are also considered bioindicator species (Risch, 1981;Eubanks, 2001;Gerlach et al, 2013;Fernandes et al, 2019).…”

“…and Odontomachus sp. has been highlightedby their importance for pest control and as bioindicator species for assessing environmental risks(Risch, 1981;Gerlach et al, 2013;Fernandes et al, 2019).…”