With the rise in concern about GMOs and pesticides on human health, we have utilized Drosophila melanogaster as a model organism for understanding the effects of Roundup-Ready® GMO diets on health. We recorded dietary behavior during and after exposure to a medium containing GMO or non-GMO corn, Roundup® in organic corn medium, and sucrose with or without one of the two Roundup® formulations. No differences in behavior were observed when Drosophila were exposed to a medium containing Roundup-Ready® GMO or non-GMO corn. Drosophila can detect and refrain from eating sucrose containing one Roundup® formulation, Ready-to-Use, which contains pelargonic acid in addition to glyphosate as an active ingredient. Drosophila exhibited dose-dependent increased consumption of sucrose alone after exposure to a medium containing either Roundup® formulation. This may indicate that flies eating a medium with Roundup® eat less and were thus hungrier when then given sucrose solution; that a medium with Roundup® is more difficult to digest; or that a medium with Roundup® is less nutritious, as would be the case if nutritionally important microbes grew on control medium, but not one containing Roundup®. View Full-Text ►▼ Show Figures This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited