PARTITIONING SEASONAL TIME - INTERACTIONS AMONG SIZE, FORAGING ACTIVITY AND DIET IN LEAF-LITTER FROGS

This study investigates hypotheses about partitioning of food resource s among all species and several size classes in an assemblage of diurn al leaf-litter frogs in central Amazonia. All species in this assembla ge change the type and size of prey as they grow. An ordination of die t composition was significantly associated with frog size and species- specific behaviour. However, a partial Mantel analysis indicated that species explained about 1.5 times more of the variation in diet overla p between individuals than frog size. Diet and foraging activity are c orrelated in juveniles, but not in adults, and this result holds wheth er species are considered as statistically independent observations or whether relationships are analysed using phylogenetically independent contrasts. This study showed that the partitioning of food resources between species changes with the population size structures. Thus, int raspecific and interspecific changes in diet, coupled with different p atterns of juvenile recruitment, cause diet segregation among species due to temporal segregation of equivalent size classes.