Fig 4. Proportions of food classes in the diet plotted against the proportion of stems in the forest bearing fruit.

Data points show values for three-month blocks. Rows indicate dietary components comprising leaves (A, B), flowers (C, D), seeds (E, F), fruit (G, H), and figs (I, J). Note that estimates of fruit availability (x-axis in all plots) are based on different calculations for the two species: plots for H. albibarbis (left column) depict the proportion of stems bearing mature and ripe fruit only, whereas plots for P. rubicunda (right column) depict the proportion of stems bearing immature mature, and ripe fruits. Lines are ordinary least squares regression lines and standard errors (solid and dotted lines, respectively). Differences in sample size reflect differences in the number of three-month blocks with feeding observations from gibbons (n = 15) and leaf monkeys (n = 20). Bold regression lines indicate that fruit availability was a predictor in the top model for that plant part.