(A) YPI of yeast-deprived female flies in which Ir76b-GAL4 neurons were all silenced, or with Poxn-GAL80, and corresponding controls. Expression pattern of experimental flies in the brain as visualized using UAS-CD8::GFP in green, with nc82 synaptic staining in gray. Arrows indicate presence/loss of GFP expression in the SEZ. (B) YPI of yeast-deprived female flies in which Ir76b-GAL4 neurons were all silenced, or with tshirt-GAL80, and corresponding controls. Expression pattern of experimental flies in the VNC as visualized using UAS-CD8::GFP in green, with nc82 synaptic staining in gray. (C) Upper: Schematic of the proboscis, showing sensilla, taste pegs and pharyngeal taste organs. Lower: Schematic view of the SEZ of flies expressing CD8::GFP from a fragment of the Ir76b enhancer (VT033654-GAL4) with GRNs colored by their peripheral innervation and gray representing the nc82 synaptic staining. Pink, taste pegs; black, sensilla; yellow, pharyngeal taste organs; purple, legs. (D) Expression of 1261-, Ir76b- and Ir25a-GAL4 in the anterior (left) and posterior (right) SEZ, with arrows showing projections from pharyngeal (yellow), taste peg (pink) and sensillar (black) GRNs. (E) Number of sips from yeast by flies with 0/1/2 copies of the PoxnΔM22-B5 mutation. The homozygous mutant also contains a rescue construct to rescue all defects except taste sensilla (see Materials and methods). (F–H) Number of sips from 10% yeast by yeast-deprived females in which 67E03- (F), Ir67c- (G) or Gr9a-GAL4 (H) neurons were acutely silenced, and corresponding controls. 67E03-GAL4 labels taste peg GRNs, Ir67c-GAL4 labels a subset of GRNs in the LSO, and Gr9a-GAL4 labels a subset of GRNs in the VCSO. In (A) and (B), circles represent yeast preference in single assays, with line representing the median and whiskers the interquartile range. In (E–H), boxes represent median with upper/lower quartiles. ***p<0.001, **p<0.01, ns p≥0.05. Groups compared by Kruskal-Wallis test, followed by Dunn’s multiple comparison test.