Effects of Transgenic Rice on Life History Traits of Daphnia magna in Life Table Experiments

To investigate the impacts of transgenic rice on freshwater organisms, we conducted two life table experiments using Daphnia magna for fifteen and twenty days, respectively. We examined life history traits such as population growth rates (r), reproductive rates ($R_0$), generation times, and survivorship. In the first experiment, we used non-drought-stressed transgenic and non-transgenic rice harvested in 2005. In the second study, we used non-transgenic and transgenic rice harvested in 2006 following drought stress. Each experiment involved three treatments in which D. magna neonates were fed with Selenastrum capricornutum (control treatment) and S. capricornutum with 5% aqueous extracts of non-transgenic rice (N-T) and transgenic rice (T). In the first experiment, D. magna showed reduced population growth rates and lowered fecundity in the N-T and T treatments. In the second experiment, D. magna receiving both transgenic and non-transgenic rice extracts showed very high mortality, low population growth rates and reproduction rates. We could not detect any significant negative effects of extracts from transgenic rice on D. magna life history traits at 95%.