Dieta do Plecturocebus cinerascens (Platyrrhini: Primates): a influência da composição química na escolha de frutos consumidos

Abstract

Plants protect themselves against herbivores in many mechanical and chemical defense mechanisms. Much of the secondary metabolites that plants produce, e.g. tannins and alkaloids, have been shown to deter herbivores. It is possible that the amount of ingested mass of fruits consumed by Plecturocebus cinerascens (Platyrrhini: Pitheciidae) is lower depending on the concentration and type of secondary metabolites (tannins and alkaloids) contained in the fruits. My fieldwork was carried out in the area of the Rondon II Hydroelectric Power Plant, Pimenta Bueno, Rondônia State, Brazil. In order to record the species of fruit consumed by P. cinerascens, I searched the animals at seven different sites, each site being the living area of a distinct Ashy titi monkey group. Once I registered the feed of a certain group of Ashy titis, I was searching for a different group in order to avoid sample pseudo-repetition. I collected fruit samples to perform chemical analysis in all plants in the fruiting stage where the animals were fed. The chemical analysis was performed both in the consumed parts and in the unconsumed parts of the fruits. The results of the multiple regression did not show a relation between the concentration of secondary metabolites and the weight of the freshy mass of the fruits consumed by Ashy titi monkeys. However, the animals discarded the parts of the fruits in the only plant species (Amorimia [Mascagnia] rigida [Malpighiaceae] and Inga sp. [Fabaceae: Mimosoideae]) that presented alkaloids. I conclude that the diet of P. cinerascens is not influenced by secondary metabolites (e.g. tannins and alkaloids) and indicates a broader investigation of the chemical composition of food items that P. cinerascens consumes to evaluate if other chemical compounds, not evaluated in this study (e.g. proteins, lipids, sugars and others), influence the diet of these primates.