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. 2013 Dec 9;110(52):21153–21158. doi: 10.1073/pnas.1320208110

Fig. 1.

Fig. 1.

Flies prefer to lay their eggs on ethanol-containing food. (A) Cartoon of egg-laying assay. (B) Given the choice between food with and without ethanol, flies preferred to lay eggs on ethanol [ANOVA: F(5,71) = 25.36, P < 0.0001; n = 13–16; Tukey’s post hoc comparisons: for 0% vs. 3%, P = 0.04; for 0% vs. 5%, 7.5%, or 10%, P < 0.0001]. (C) The total number of eggs laid is not significantly affected by the presence of ethanol [ANOVA: F(5,66) = 1.46, P = 0.22; n = 11–13]. (D) Flies preferred to lay their eggs on 5% ethanol over 1% [Wilcoxon: χ2(1,8) = 6.05, P = 0.01], 3% [χ2(1,8) = 6.05, P = 0.01], or 10% [χ2(1,18) = 16.31, P < 0.0001] ethanol. There was no preference between 5% and 7.5% ethanol [χ2(1,10) = 0.48, P = 0.49]. (E) The number of eggs laid on ethanol concentrations lower than 5% was significantly greater than those laid on concentrations higher than 5% [ANOVA: F(3,26) = 249.45]. (F) Oviposition preference depends on the context of the oviposition substrate. Two-choice tests between 1%, 3%, 5%, 7.5%, and 10% ethanol suggest that concentrations near 5% ethanol are preferred. Preference indices for all pairwise comparisons are summarized. Detailed data are shown in Fig. S2. Bars on graphs represent means ± SEM. *P < 0.05; **P < 0.001; ***P < 0.0001.