(A) For preference assay, 15 larvae are tracked in an odor gradient for 15 min. Trajectories demonstrate avoidance/attraction to GA by fed/food-deprived larvae. (B to D) Electron microscopy (EM) reconstructions (left) and behavioral phenotypes (right) for ORNs, uPNs, and cobra mPN [mushroom body calyx (CA), vertical lobe (VL), larval antennal lobe (lAL; circled), lateral horn (LH)]. (B) GA elicits avoidance in fed state (one-sample t test, P < 0.001) and attraction after food deprivation (P < 0.01). Behavior diverges between states (two-sample t test, ***P < 0.001). Anosmic larvae (Orco−/−) ignore GA [one-sample/two-sample t tests, not significant (n.s.); n = 12 to 18]. (C) Silencing uPNs (GH146-GAL4) specifically abolishes food-deprived attraction [one-way analysis of variance (ANOVA), *P < 0.05; n = 8 to 10]. (D) Silencing cobra mPN (GMR32E03-GAL4) specifically abolishes fed avoidance (one-way ANOVA, ***P < 0.001; n = 6 to 10). (E to G) Calcium responses to GA (10−6). (E) ORN-Or82a and ORN-Or45a exhibit similar responses in both states (n = 5 to 6). (F and G) After food deprivation, uPNs exhibit increased responses (n = 7 to 9), whereas cobra mPN exhibits more negative responses (n = 8 to 9). (H) Parallel lAL output pathways (uPNs and cobra mPN) support opposite behavioral responses and receive opposite state-dependent modulation.