Figure 5. Discriminant analysis of female (A) and male (B) flies of all eight strains, projected onto the first two principal components.

Probability ellipses correspond to 95% probability. The various components in the cuticular cocktail (A-X) were also projected onto these components (arrows) to give a sense of the dimensionality. For each sex, we conducted a forward stepwise discriminant analysis (with an entry threshold value of p = 0.05 and a removal threshold value of p = 0.10) using the additive/log ratio transformed proportion of the CHs) using the absolute amount of the uncorrelated CHs as quantitative variables and the strain as a qualitative variable. Magenta arrows indicate C7 compounds, cyan arrows indicate C5 compounds, black arrows indicate others compounds. For legends, see figure 4.