Fruit Selection by a Forest Guenon
Résumé
(1) This paper analyses the frugivorous diet of Cercopithecus cephus through one annual cycle in comparison with variations in fruit species availability, fruit morphology and nutrient and mineral content of fruit. (2) Among the whole spectrum of fruiting species available, a small fraction (termed edible species) is included in the monkeys' diet. (3) Among these edible species, some are more frequently sampled by monkeys than expected by their density, whereas several abundant species are only occasionally eaten. Overall, twenty species (35% of those sampled) contribute to 85% of the diet; among them, only three are included in the list of the twenty most abundant plant species in the study site. (4) According to their selection ratio (percentage sampled/percentage abundance), fruit species have been classified into three categories: preferred, neutral and avoided species. These three categories differ by their nature, their colour and their chemical composition. (5) Brightly coloured fruits possessing either a succulent pulp or arillated seeds are largely eaten: they possess either a high water content and a high sugar content (succulent pulp) or a high protein content and a high fatty acid content (arils). (6) Dull-coloured fleshy fruits are avoided: they possess a relatively low nutritive value and a high concentration of fibres. (7) The most preferred species exhibit a high acidity content. (8) We discuss the different levels of selection exerted by monkeys and underline the difficulties involved in the assumption that fruits constitute a superabundant food resource or alternatively are a limiting resource in tropical rain fore