Patterns of diet composition of a whiptail lizard species conforms to the Shared Preferences Model of interindividual variation in prey consumption

Abstract

We analysed the interindividual variation in diet, patterns of food resource use and topology of the trophic networks of juvenile, male, and female Ameivula ocellifera (Spix, 1825) during one year, covering wet and dry seasons. Using a network-based approach, we evaluated the degree of variation in the diet of individuals, and the degree of nestedness and clustering to identify patterns of resource use and the topology of individuals food webs. We found a high degree of interindividual variation in the diet of juveniles, males, and females during the study period, which seems to be related to nested patterns of resource use of males and females. These results also suggest that males and females seem to have both generalist and specialist individuals, of which the diets of specialists are nested within the diets of generalists. For juveniles, we found evidence of interindividual variation in diet in both seasons, although patterns of food resource partition that may cause it could not be identified. Insect larvae of several groups were the main food resource in all three lizard groups during the wet season, while termites were the dominant food item during the dry season. Our results conform to the Shared Preferences Model where individuals should consume the same top-ranked prey when they are abundant in the environment, replacing it with suboptimal items as preferred ones become scarce.