Equatorial region of eye imaginal discs where E(spl) mδ0.5 expression (green) becomes restricted to a single photoreceptor in each cluster (magenta), as detected in control and Dl∆β1-2/+ discs (top panels). In Df(3R)DlFx3 /+ and Dl∆β1-2/Df(3R)DlFx3 discs (bottom panels) E(spl) mδ0.5 expression is reduced (Df(3R)DlFx3 /+) or absent from several clusters (Dl∆β1-2/Df(3R)DlFx3) indicative of reduced Notch signalling. Scale bars correspond to 10 μm. 