In conclusion, our results partially confirm findings of both sides of the contesting research groups [19][20][21][22]24,34] but they also differ in a number of aspects. From the published controversy, it seems that no party contests that gut microbiota play a significant role in the impact, or rather the unfolding of the impact of B. thuringiensis bacteria, spores and toxins on lepidopteran larvae. The core of the controversy centers around the question whether or not B. thuringiensis and its by-products are the main act or only have a support role-or, as Raymond et al. [23] have put it, whether B. thuringiensis is an 'impotent pathogen' or a full (killing) pathogen on its own right? With our studies, we cannot-and did not intend to-answer the question regarding the bacterial organism B. thuringiensis. However, we can answer the question regarding GM maize plants expressing solely more activated forms of the Cry toxin Cry1Ab. In our experiments, Cry toxins were the main act but with gut microbiota having a significant support role in conjunction with plant compounds. While the antibiotic treatment may have had an immune stimulating effect rendering the insects more tolerant to toxicemia, the lack of an effect in the survival or weight gain **data** of antibiotic treated larvae on control plants does not point to this effect. More research is needed, however, to reveal such underlying mechanisms further.