Figure 2.

Learning curves (absolute conditioning; portion of bees showing conditioned proboscis extension response (PER)) for the four aromatic compounds tested: (a) ‘h-ACP’ (triangles), (b) ‘d8-ACP’ (squares), (c) ‘h-BNZ’ (circles), (d) ‘d6-BNZ’ (diamonds), (e) curves a–d overlaid to show similarity. Shaded areas show 95% confidence intervals (CIs); the differences between curves are not significant (F-tests; F = 0.87–1.25; p = 0.18–0.49; d.f. = 60–84); t-tests for individual trials did not show significant differences except for trial no. 3 where response to h-BNZ is different from those to h-ACP and d8-ACP (*p < 0.05; note that these differences are not significant after Bonferroni correction for multiple comparisons). (Online version in colour.)