Anthropology, University of Toronto
Saturday 2:00-2:15, Ballroom A
Despite extensive research on Neotropical primates, there are few data on the evolutionary ecology of body size variations in extant Pitheciinae (Callicebus, Pithecia, Chiropotes, and Cacajao) in differing ecological communities. I first tested the energetic equivalent rule (EER) in non-flooded and flooded forests, which predicts that density and body size will be negatively correlated and exhibit of slope of -0.75. I also tested for phylogenetically structured environmental variation (PSEV) as a model for the evolution of Pitheciinae body size variations. PSEV refers to the shared attributes that related taxa have acquired because they tend to have occupied similar niches during their evolutionary history. Species-specific data on phylogenetic relationships, density, and body mass were collected from the literature. Regression models indicated that the EER can only be applied to Callicebus in non-flooded forests and to Pitheciini (Pithecia, Chiropotes, and Cacajao) in flooded forests. Partitioning methods revealed that Pitheciini body size variations are the result of PSEV in non-flooded forests and phylogeny in flooded forests. The evolutionary ecology of Pitheciini body size variations in differing ecological communities is best explained as resulting from stabilizing selection to meet metabolic needs and to deal with predation pressures.
Supported in part by an NSERC Discovery grant