PMC

Illustration of two alternative patterns of population niche expansion. A population that uses a narrow range of prey sizes can increase its population niche breadth (bold lines) in two ways. (a) All individual niche breadths (thin lines) can expand resulting in no increased niche variation among individuals. (b) Individual niche breadths can remain limited, whereas individuals diverge from each other to increase among-individual variation.

Correlation between diet variation among individuals (V) and the TNW of the population (see Materials and Methods for details). The empirical results are shown with filled circles. Crosses (and the dotted regression line) indicate the expected trend under a null model in which diet variation arises solely by individuals randomly sampling a limited set of prey from a shared prey distribution. Diet variation for Anolis lizards was measured based on variances of prey sizes (BIC/TNW) rather than the Shannon–Weaver diversity index. Hence, the scale for both diet variation and niche breadth are different from the other taxa.