Takemoto / Poster

Feeding selectivity in leaves of wild chimpanzees, Bossou, Guinea : the role of phytochemistry.

Hiroyuki Takemoto
Primate Research institute, Kyoto university

     Plant chemistry plays an important part in the food choice of primates. However, because animals probably seek out a different chemical component for each category of food item they ingest (fruit for sugar, leaf for protein, pith for water, and so on), it is difficult to interpret food choice in all food categories using the same chemical components. For chimpanzees, which are basically frugivorous, a number of studies have analyzed their fruit eating behavior. In contrast, little is known about the relationship between leaf eating behavior and plant chemistry.
     In this study, I examined phytochemically the components of leaves from tree species to access the criteria of leaf food choice by chimpanzees. Field data were collected for 8 months from 1995 to 1996. Time budgets of leaf eating, relative dominance and young leaf abundance were estimated each month for each tree species. Phytochemical analysis of dried plant material consisted of tests for crude protein, crude fat, neutral detergent fiber, ash, and condensed tannin content.
     It was found that 1) leaves eaten contained a significantly higher ash content and lower condensed tannin content than leaves not eaten., 2) feeding selectivity of leaves was related to crude protein and fiber content. Consequently, it seems reasonable to suppose that there is are different phytochemical relationships between edible and non-edible versus,prefered or not prefered leaf food. Protein and fiber content does not appear to be a relavant criteria for chimpanzees when deciding what leaves to eat. Two main criteria, mineral and secondary compound content, were found to strongly influence the consumability of leaf material by chimpanzees.