What does the Geometric Framework tell us about change in nutritional requirements?

FERNANDEZ, VANINA A; KOWALEWSKI, M MARTIN; ROTHMAN, JESSICA

Recife

Congreso; II Congresso Latino Americano XV Congresso Brasileiro de Primatologia; 2013

Sociedad Brasileira de Primatologia-Sociedad Latinoamericana de Primatologia

Folivore-frugivore primates eat foods that vary widely in their macronutrient compositions. The "Geometric Framework" (GF) proposes a multi-dimensional model that represents the dynamic interactions of an animal with its environment in the context of multiple nutrients, in order to get an optimal mixture of these nutrients (?nutritional target?). An animal?s nutritional requirements depends on physiological and environmental factors that cause changes in short and long term strategies used by individuals to regulate energy and nutrient intake. Although the GF has recently been applied to primates; the available information remains scarce across species. We present preliminary data on the nutritional ecology of A. caraya in Corrientes, Argentina. We collected 616 hours of group observation (June to December 2010, two groups) and 35 full day focal follows (3 males and 5 females). We quantify bite/minutes and feeding rates, bite weight and nutritional composition of 142 samples of food eaten (26 species) and estimated daily and seasonal intake of protein (PE) and non-protein (NPE) energy. By means of GF we constructed a complete dietary pathway of total protein and non-protein energy intake for each individual and looked for sex and seasonal differences. We found seasonal differences in PE (Winter: 225.6±112.6, Spring: 104.7±38 KJ/day/mass) and NPE (Winter: 1151.4±739.3, Spring: 1982.6±1104.32 KJ/day/mass) target intake, but there was no differences between sexes. Nevertheless, we found that individual?s nutritional targets change through the year, probably following a monthly pattern. In order to understand how an animal?s nutritional target could change could allow us to understand not only the adaptive capacity of organisms to environmental changes but also how howlers are capable of coping with marginal environments across their distribution.