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. 2024 Aug 15;15:7041. doi: 10.1038/s41467-024-50808-w

Fig. 2. Persistent behavioural tracking of noni odours in D. sechellia.

Fig. 2

a Tethered fly behavioural assay. ΔWBA: left-right difference of standardised wing beat amplitudes, TTL: transistor–transistor logic. b, c Odour-tracking of noni juice and H2O in wild-type D. sechellia and D. melanogaster (b) and D. sechellia Or and Ir mutants (c). Left, time course of ΔWBA (mean ± SEM) where black bars indicate odour stimulation (ten 500 ms pulses with 500 ms intervals). Right, quantification in 1 s time windows immediately prior to stimulus onset (“pre”) and individual stimulus pulses (“1–10”). Mean ± SEM are shown. Paired t test (two-sided): ***P < 0.001; **P < 0.01; *P < 0.05, otherwise P > 0.05. n = 30 animals each. d Left, example flight trajectories in the x-y plane of D. sechellia, D. melanogaster (a hybrid Heisenberg-Canton-S (HCS)) and D. sechellia Or22aRFP mutants in a noni plume. Right, occupancy heat maps of trajectories that came at least once within 10 cm of the plume centreline for Dsec07 (n = 835 trajectories, 7 recording replicates, 105 flies), DmelHCS (n = 1346 trajectories, 4 recording replicates, 60 flies), DsecOr22aRFP (n = 509 trajectories, 6 recording replicates, 90 flies). e Annotated view of the wild-type D. sechellia trajectories (from d) illustrating analyses in f, g. Based upon the trajectory distribution, we inferred that the noni juice plume sank by ~5 cm from the odour nozzle to the end of the tracking zone (Methods and Supplementary Fig. 4d–f). f Mean radial distance of the point cloud from the plume centreline for the trajectories in d. Data were binned into 5 cm y-z plane cross-sections starting 5 cm downwind from the plume origin, and restricted to 10 cm altitude above or below the estimated plume model. Non-parametric bootstrapped comparison (1000 iterations) of medians: P < 0.001. g Kernel density of the course direction distribution of points within a 3 cm radius of the plume centreline (orange circle on cross-section in e), further parsed into the point cloud in the downwind or upwind halves (e). Downwind half kernels: Dsec07 (15,414 points, 367 trajectories), DmelHCS (20,912 points, 511 trajectories), DsecOr22aRFP (3,244 points, 164 trajectories). Upwind half kernels: Dsec07 (136,827 points, 501 trajectories), DmelHCS (80,594 points, 615 trajectories), DsecOr22aRFP (40,560 points, 286 trajectories).