Figure 1. Flies show taste-dependent consumption preference for food containing vitamins.

(A) Schematic diagram of the two-choice radiolabeled food intake assay. Flies have access to medium with or without vitamins, and only one of the food patches is radiolabeled in each vial. (B-C) Dahomey females (B) and males (C) consume more of the vitamin-containing food. A time-course for cumulative food intake is shown over 24 hours. Flies had access to two food patches, FLYaa medium with (+) or without (−) vitamins. Each time point is a subsample of 5 replicates of 10 flies each. (D-E) Vitamin consumption preference is sexually dimorphic. Females (D) in all 4 strains tested show preference for both folic acid and riboflavin. Males (E) only show preference for folic acid. (F) Vitamin consumption preference is dependent on taste. Tested lines with “normal” taste include w¹¹¹⁸ and the heterozygous Poxn controls. External taste-deficient animals are a heteroallelic combination of the Poxn⁷⁰ and Poxn^ΔM22 mutants, with or without one of the two transgenes necessary for silencing Ir25a-expressing neurons. Taste-blind animals (Poxn⁷⁰/Poxn^ΔM22; Ir25a-Gal4>UAS-Kir2.1) are the Poxn heteroallelic mutant with pharyngeal GRNs silenced. In all panels, each point represents 1 vial of 10 flies. Panels D-F show consumption preference over 24 hours for FLYaa with (+) or without (−) the indicated vitamin (folic acid: 1.13 μM; riboflavin: 1.36 μM). *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001 (unpaired t-test). Data are shown as mean ± SD. See also Figures S1 and S2.