In the present work, we aimed to evaluate: 1) the influence of the Cry1Ac protein expressed by the genetically modified cotton variety (Bt) NuOpal, on the biological parameters of a non-target pest, Aphis gossypii, reared under laboratory conditions; 2) the influence of plant age on aphid development. Cotton cultivars were grown following technical advice. In the laboratory, the aphids were separated into plastic containers including a cotton sheet, which was changed daily with the help of a moist cotton cloth. Observations were carried out daily, and the duration of the immature and adult stages, and offspring number, were recorded. Our results show that regardless of the differences in the duration of each instar, cultivars Bt and non-Bt and the different ages of the plant to Bt, no differences were seen in the total duration of these phases. It was only during the reproductive period that differences were observed among genotypes for 120 days. Regarding the number of offspring and longevity total, there were differences between the different ages of the Bt treatment.

Cultivation of Bt crops is an important tactic in integrated pest management. The effect of Bt maize on arthropod predators needs to be investigated because of the important role of these natural enemies in the absence of target pests. The objective of the present study was to generate information on the distribution model of Cycloneda sanguinea (L.) (Coleoptera: Coccinelidae) in Bt and non-Bt maize. A sampling field of 2.500 m 2 area, divided into 100 plots, was used in this study. Five plants per plot, totaling 500 plants in each field, were studied. We counted the total number of adults every week, totaling six samples for each field (Bt and non-Bt). The aggregation index (variance/mean ratio, Morisita index, and exponent k of the negative binomial distribution) and Chi-square fit of the observed and expected values to the theoretical frequency distribution (Poisson, binomial, and negative binomial positive) revealed that, in both cultivars, the adults of C. sanguinea were distributed according to the random distribution model, which fits the pattern of Poisson distribution.