Fig. 3. Analysis of visual and textural contributions to D. sechellia’s noni preference.

a Single-fly oviposition preference assays in the dark for noni juice versus apple cider vinegar in agarose (fly strains as in Fig. 1c). Left: oviposition preference index. Statistically-significant differences from 0 (no preference) are indicated: ***P < 0.001; **P < 0.01 (Wilcoxon test with Bonferroni correction for multiple comparisons); N = 60 flies across 2 technical replicates. Right: egg-laying rate in these assays; Kruskal-Wallis rank sum test with Nemenyi post-hoc test. Statistically-significant differences from the D. melanogaster CS strain are indicated: ***P < 0.001; *P < 0.05; NS P > 0.05. b Group color preference assays in which flies are given a choice to enter two traps containing the same chemical stimulus (balsamic vinegar (D. melanogaster and D. simulans) or noni juice (D. sechellia)) and distinguished only by colored casings with different light and background conditions. Statistically-significant differences from 0 (no preference) are indicated: *P < 0.05; NS P > 0.05 (Wilcoxon test with Bonferroni correction for multiple comparisons); N = 12–24 assays across at least 2 technical replicates. c Single-fly oviposition preference assays testing between the agarose concentrations indicated at the top and 0.5% agarose in the counter-substrate. Both substrates contain apple cider vinegar (D. melanogaster and D. simulans) or noni juice (D. sechellia). Statistically-significant differences from 0 (no preference) are indicated: ***P < 0.001; **P < 0.01 *P < 0.05; NS P > 0.05 (Wilcoxon test with Bonferroni correction for multiple comparisons); N = 30–60 flies across 1-2 technical replicates. d Graph recapitulating data from c. Dots represent the mean values and the bars represent ± SEM. The statistical comparisons shown are between the most similar strains of the different species: ***P < 0.001; NS P > 0.05 (Kruskal-Wallis rank sum test with Nemenyi post-hoc test). e Close-up image of noni fruit illustrating the concentration of D. sechellia eggs in the pedicel cavity (where the fruit was attached to the stem) and in the flesh exposed by a skin break. Flies were placed in a group assay oviposition chamber containing whole noni fruits during 72 h. f Graph of stiffness of substrates of different agarose concentrations (in noni juice), overlaid with the stiffness ranges of unripe and ripe noni fruits (illustrated in the photos) within the pedicel cavity or on the external skin. Measurements were made using Semmes-Weinstein Monofilaments following the procedure described in⁷⁸. Exact P values for the statistical comparisons are provided in the Source Data files.