Fig. 1. ILP2 is required to suppress futile courtship.

(A and B) Intermale courtship in ilp2¹ and ilp5¹ males. Courtship index and single-wing extension number between two males of various ILP (ilp) mutants. Intermale courtship of Canton-S (C.S.) as the wild-type control. N = 6 to 13 in each group. (C and D) ilp2¹ males’ courtship toward virgin or newly mated w¹¹¹⁸ female. Courtship index and single-wing extension number between tester males and virgin or mated w¹¹¹⁸ female. Mated w¹¹¹⁸ female indicated female with immediately completed courtship. ilp2¹/+ was used as the parental control. N = 7 to 16 in each group. (E and F) ilp2¹ male chased D.sim virgin female intensely. Courtship index and single-wing extension number between tester males and virgin D.sim female. N = 8 to 17 in each group. (G and H) Intermale courtship was induced by silencing IPCs. Courtship index and single-wing extension number between tester males. Ilp2-Gal4 and ilp3-Gal4 were used to drive Kir2.1 expression in IPCs. N = 5 to 6 in each group. (I and J) Male contacts induced the release of ILP2. Immunostainings of ILP2 in male IPCs when males were housed alone (Mock), coupled with female or male. Mean gray values [arbitrary units (AU)] of IPCs were quantified between groups. Scale bar, 10 μm. N = 11 to 15 in each group. In all analyses, one-way analysis of variance (ANOVA) followed by Dunnett’s test for multiple comparisons was used, and statistical differences were represented as follows: *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001. Data were represented as means ± SEM.