Multi-generational Effects of Glyphosate on Drosophila melanogaster

SMSU Event Center BC

Glyphosate, the active ingredient in Roundup, is a non-selective herbicide. It is the most widely used pesticide worldwide due to indiscriminate ability to kill weeds. Although originally believed to only affect plants because of its effect through the shikimate pathway, which animals lack, studies indicate that glyphosate affects animals and microorganisms. This leaves questions about whether those effects are passed to offspring from generation to generation. My goal is to identify multigenerational effects of glyphosate on population survival of Drosophila melanogaster. Population size and individual behavior will be used to track changes in population viability through multiple, non-overlapping generations until no flies survive in one population of each pair, one exposed to organic and one glyphosate-containing medium. Fifty adult flies will be placed into each bottle containing either organic or 2g/l glyphosate medium. At 7 days, adult flies will be cleared, and at 16 days the numbers of new flies counted and transferred to new medium. This will be repeated with the same timing. Behavioral viability (activity) will be measured for new adults from both treatments each generation. Preliminary data show that populations exposed to glyphosate crash after 5-8 generations, while organic controls are fully viable, suggesting that negative effects accumulate from generation to generation. Behavioral observations suggest viability loss as early as generation 3. Comparing these variables through multiple generations of paired populations will give insight into the effects long-term glyphosate exposure across multiple generations can have on non-target organisms.