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. 2011 Jan 11;36(3):223–235. doi: 10.1093/chemse/bjq128

Figure 4.

Figure 4

Comparing innate behavior to associative learnability: AM–LIN. (A) Innate preference: Experimentally naïve animals are given the choice between an odor and a no odor condition (EM). Larvae approach undiluted AM but not undiluted LIN, when tested against EM (OSS tests: P < 0.05/2 for AM and P = 0.135 for LIN; N = 21, 46). Correspondingly, preference for AM is higher than for LIN (MWU-test: U = 2; P < 0.05). The shading of the box indicates significant difference from chance level (OSS tests above). (B) Relative innate preference: Larvae prefer undiluted AM over undiluted LIN (OSS test: P < 0.05/6; N = 10); as AM is diluted, preference for AM is reduced but remains significant (OSS tests: P < 0.05/6 in all cases; N = 10, 14, 12, 14, 34). The median scores from the inset figure are plotted against AM dilution. The shading of the boxes indicates significant difference from chance level (OSS tests above). Based on these results, we chose a 1:1600 dilution of AM and undiluted LIN in the learning experiments in (C). (C) Learnability: In the 2 cases to the left, larvae are trained and tested with either AM versus EM (group 1) or with LIN versus EM (group 2); both groups show significant learning effects (OSS tests: P < 0.05/2; N = 26, 24). Larvae show higher associative performance indices for AM than for LIN (MWU-test: U = 84; P < 0.05; sample sizes as above). In all 3 cases to the right, larvae are trained differentially with AM versus LIN but are tested with either both odors (group 3) or with only AM versus an empty container (group 4) or with only LIN versus an empty container (group 5). When AM as the odor with higher learnability is omitted at test, scores are reduced (group 3 vs. 5, MWU-test: U = 213.5; P < 0.05/2; N = 30, 28), whereas omission of the low-learnability odor LIN at test is without effect (group 3 vs. 4, MWU-test: U = 425.5; P = 0.57; N = 30, 31) (a KW test across the 3 groups reveals: H = 13.38; degrees of freedom = 2; P < 0.05; sample sizes as above). Other details as in the legend of Figure 2. This figure appears in color in the online version of Chemical Senses.