Figure 1. Path diagrams showing the standardized regression weights and the amount of variation in each variable explained by the input arrows (R²).

Straight arrows reflect causal paths, with the strength of the relationship designated by arrow thickness. Curved arrows designate correlations. Asterisks denote statistically significant paths: *p<0.02, **p<0.001. Paths that are significantly different between sun and shade treatments are indicated with †. Results of the ‘phenotypic’ SEM on all individuals are shown in panels A (sun, N = 682) and B (shade, N = 681); those of the ‘population’ SEM on population means are shown in panels C (sun, N = 8) and D (shade, N = 8).