Fig. 5: Learning abilities differ across species.

a, b Flies (D. melanogaster: red; D. simulans: blue; D. sechellia: green) were trained to associate an odor (farnesol: circles, hexanoic acid: triangles, 4-methylcyclohexanol: squares or 3-octanol: stars) or its solvent (mineral oil) with punitive electric shocks using a single regimen of shocks (a) or six regimens of shocks (b) and learning was measured as a Performance Index; the Performance Indices obtained for the odor-pairing and the reciprocal pairing was averaged. See Supplementary Fig. 9 for individual Performance Indices. The statistical significance, or p-value, was measured using the sample t test using 0 as the hypothetical mean (*p-value < 0.5, **p-value < 0.01, ***p-value < 0.001, ****p-value < 0.0001; n ≥ 7, standard deviation from mean is shown). (c, d) The Performance Indices obtained for a given odor in a particular species (farnesol: circles, hexanoic acid: triangles, 4-methylcyclohexanol: squares or 3-octanol: stars) were plotted against the cumulative frequencies of the glomeruli known to be activated by a particular odor (based on a previous study³³; Supplementary Table 2); the R² values obtained for each regression line are shown. All source data used in this figure are provided in the Source Data file.