Fig. 1

Sampling schedule with one line per subject ordered from bottom by increasing age categorized into young adult (6–10), mid-aged (> 10 and < 18), and old (≥ 18). The successive sampling windows correspond in chronological order to the rich, lean, and intermediate season, respectively. The lower panel shows food availability in the three sampling periods. Boxes represent the interquartile range (IQ), which contains the middle 50% of the records, and a line across the box indicates the median. Vertical lines extend from the upper and lower edges of the box to the highest and lowest values which are no greater than 1.5 times the IQ range. Circles represent outliers