Fig 1.
Plot of general forest productivity for gibbons (A: the proportion of stems in the forest bearing mature and ripe fruit) and leaf monkeys (B: proportion of stems bearing immature, mature and ripe fruit).
There was substantial variation in fruit availability over the course of the study period. The size of the points represents the number of feeding observations for each three-month block.
Fig 2.
Rarefaction curves indicating the dietary richness of P. rubicunda and H. albibarbis.
Dietary richness (number of genera) as a function of time (months of observation) for (A) all food classes and (B) only the frugivorous portion of the diet. Overall diet richness was greater for leaf monkeys (P. rubicunda) than for gibbons (H. albibarbis, A), but the species did not differ in the number of genera of fruits they consumed (B). Error bars represent +/- 1 standard deviation from the mean.
Table 1.
Contribution of various food classes and dietary overlap measures for gibbon and leaf monkey diets.
Fig 3.
Feeding selectivity in gibbons (3a) and leaf monkeys (3b).
Closed circles indicate availability (proportion of fruiting observations of genus i, out of total fruiting observations), open triangles indicate use (proportion of the diet), and error bars are 95% confidence intervals. Non-overlapping confidence intervals indicate positive selectivity (when triangles (use) are to the right of circles (availability)) or avoidance (when triangles (use) are to the left of the circles (availability)). Genera are listed from top to bottom in decreasing order of absolute selectivity values.
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.