APP and Alzheimer disease: In this study, two different Drosophila AD models (Aβ1-42-expressing flies and AβPP-BACE1 co-expressing flies) were analysed in parallel and compared with respect to toxic effects (assessed by the eye phenotype and by longevity and locomotor assays) and to levels of the Aβ1-42 peptide to evaluate how the toxic effects might be linked to the level of Aβ1-42 and/or how the peptide is generated.