To attract seed dispersal agents, most Neotropical tree species produce edible fruits. Animals eat the fruits, often swallowing the seeds, which may be deposited away from the parent tree. Data show that not all frugivores in a given habitat are equally attracted to the same fruit species. Though numerous factors can influence fruit choice, the nutrient value of the pulp to the disperser is clearly of key importance. Here data are presented on the macronutrient content (total crude protein, fat and nonstructural carbohydrate) of 19 fruit species collected from a single forest site, Barro Colorado Island in central Panama. The only criterion for analyses was that each species produce fruits consumed by at least two primate species at this site. Though all fruit species contained a measurable amount of each macronutrient class, there were often striking differences in the amount contributed per class. Overall, two species (10.5% of the total sample) were highest in protein, five (26%) were highest in fats and twelve (63%) were highest in nonstructural carbohydrates. Fruit species in the same family or genus did not necessarily show the same macronutrient pattern. Similar data from a range of Neotropical sites could prove useful in formulating hypotheses related to community fruit-disperser relationships.

We summarize our re-examination and extension of the Groves (2001) parsimony analysis of Woolly monkeys, genus Lagothrix, which led him to conclude that the species flavicauda is not most closely related to lagotricha but to Ateles, the Spider monkeys. As a consequence, Groves further proposed that the Yellow-tailed woolly monkey should be assigned to a separate genus, Oreonax, previously erected by Oldfield Thomas (1927). Our analysis, while closely following his methods, samples a greater diversity of species and sub-species representing all the living ateline genera and makes minor revisions in Groves' data matrix of craniodental characteristics. With this broader analysis we show that Groves' cladistic results cannot be replicated except by duplicating his study using only a restricted range of taxa. A more wide ranging taxonomic sampling fails to link consistently flavicauda and other ateline species, in any particular cladogram topology, while the overall craniodental morphology of flavicauda does not separate it from lagotricha. Groves' cladistic conclusion is likely to be an artifact stemming from a chance combination of the particular taxa used as a study group and selection of characters that may not be appropriate in intergeneric comparison. There is thus no justification for recognizing Oreonax as a distinct genus, and its usage should be rejected.

From January 2000 to March 2001 we evaluated aspects of temporal variation of activities, diet, and group size of an Ateles chamek population in an area of humid mountain forest (Estación Biológica Tunquini - EBT) in the Bolivian Yungas. We also evaluated (from April 2000) the availability of fruit species consumed by these primates. We found negative correlations between the proportion of time dedicated to resting and traveling, as well as between feeding and traveling, but no correlations were found between other combinations. The diet of these primates was highly frugivorous with a low consumption of leaves and others items. The species most consumed were Protium montanum, Casearia mariquitensis, Podocarpus sp., Anomospermum sp., various species of the genus Ficus, an undetermined species (known by the common name “canelón”), and various species of the family Lauraceae. The monthly median of the number of individuals per group did not present an evident peak, but did present a tendency towards a positive relation with non-Ficus fruits. Regarding fruit availability, we observed an increase of non-Ficus species around the beginning of the wet season, whereas Ficus species had fruits available during all months of the study. Finally, we found a negative relationship between the fruit availability of non-Ficus species and the time spent in traveling.