FRUGIVORY AND SEED DISPERSAL BY RED HOWLER MONKEYS - EVOLUTIONARY ASPECT

The analysis of morphological characters of fruits eaten by Red Howler Monkeys (Alouatta seniculus) in French Guiana, shows that howlers mainly consumed juicy fruits with bright colours and few well protected seeds. However, monkeys can be associated with seed dispersal of species bearing fruit with a hard and indehiscent external coat, that only mammals are able to open with their teeth, or with large seeds that most birds, bats, or other small frugivorous animals cannot ingest. This happens in the family Sapotaceae the fruits of which often simultaneously show both characteristics, and which is the dominant family in this monkey's diet, at the Nourague Station. We also observed that the howler monkey and probably other frugivorous primates like the Spider Monkey (Ateles paniscus), is one of the main consumers and dispersers of Sapotaceae in our study site. An analysis of seedling populations under sleeping sites of howler monkeys indicates that they could be considered as efficient dispersers for this plant family. Moreover, the aggregative pattern of seed dispersal by howlers could be at the origin of the clumped distribution of most Sapotaceae. All these observations enable us to hypothesise the occurrence of a <<diffuse coevolution>> between primates and fruits of the Sapotaceae.