C Expression of the Gr28b.c-GAL4 reporter in subsets of Gr66a-positive GRNs. First panel shows that all bitter responsive GRNs are labeled by Gr66a-I-GFP (anti-GFP, green). Second panel shows the expression of the Gr28b.c-GAL4, crossed with UAS-DsRed (anti-DsRed, red). Third panel shows merged image of first and second panels. Forth panel shows a schematic diagram of sensilla arrangement. Red-marked sensilla indicate the expression of Gr28b.c-GAL4 reporter in second panel. Scale bars represent 40 μm. 