Population-scale laboratory studies of the effect of transgenic plants on nontarget insects
Authors: Schuler, T.H., Denholm, I., Jouanin, L., Clark, S.J., Clark, A.J., Poppy, G.M.
Journal, Volume, Year: Molecular Ecology, volume 10:1845-1853, 2001
Two lines of Brassica napus (Cry1Ac and a proteinase inhibitor, oryzacystatin I) and their isolines were tested for adverse effects on a hymenopteran parasitoid (Diaeretiella rapae) and the aphid host Myzus persicae in large population cages. No detrimental effects on the parasitoid's ability to control aphids were observed, but the conclusions of this study are highly suspect (see comments).
The statistics on this study are incorrect and the study is pseudoreplicated. The authors state that one treatment is parasitoids or no parasitoids. This treatment was applied to a cage as a whole, making the cage the experimental unit, not the individual plant. The authors used the plant as an experimental unit, leading to an n much higher than in reality. Also, one of the cages without parasitoids was found to have been exposed to parasitoids, so its data was discounted. This means that there was now only one replicate of the control treatment (no parasitoids), not four as the authors said.