Fruit Preferences of Ateles belzebuth in Tinigua Park, Northwestern Amazonia

Abstract

Spider monkeys are known to be highly frugivorous, relying on a great diversity of ripe fruits. However, there is controversy regarding their classification as specialized frugivores that choose certain types of fruits, e.g., lipid-rich fruits, or generalist frugivores, because they tend to consume the most available fleshy fruits in the environment. We combined data on fruit morphology, phenology, and demographic information for 202 plant species with nutritional information for 78 species, to assess feeding preferences of free ranging white-bellied spider monkeys (Ateles belzebuth) over 2 yr in Tinigua National Park, Colombia. We used simple and multiple regression analyses to predict fruit feeding time and preference, quantified via behavioral follows of focal individuals (1567 h). Spider monkeys spent more time consuming fruits from productive and abundant plants. These variables had the highest explanatory power, but predicted only 22% of variation in feeding times. Fruit preference was also positively associated with diameter-at-breast height (DBH) and negatively associated with the consumption of species producing mainly in periods of fruit scarcity. Spider monkeys consumed both sugar-rich, e.g., Gustavia hexapetala, and lipid-rich, e.g., Oenocarpus spp., fruits more than predicted from their abundance. Overall, the results show that, at Tinigua Park, spider monkeys are generalized frugivores, as they mainly consume productive species, and do not specialize on lipid-rich fruits. Large data sets are necessary for a good description of primate diets when they inhabit diverse tropical forests; nonetheless it is difficult to find variables that explain a large proportion of the variation in feeding times, because dozens of species are included in the annual diet and exceptions will always occur in relation to preferred plant traits.