Frugivorie et transport des graines de Cecropia par les chauves-souris en Guyane

(Uploaded by Plazi for the Bat Literature Project) The consumption of fruits by diurnal or nocturnal vertebrates has been· shown to be correlated with certain fruit characteristics. Fr_1:1_its _which remain green at maturity (cryptic) are consumed mainly by nocturnal vertebrates whereas fruits which coilfrast With the environment are eaten by diurnal vertebrates. As an example, species of the genus Cecropia have been analysed. C. sciadophylla, eaten mainly by birds, has pale orange colorec1 fruits which at maturity change morphologically by swelling. In C. ob1usa and C. palmata the infrutescences are crypticaJIYgfeen colored and undergo no visual change at maturity. These last two species are mainly eaten by bats. The feeding behavior of Artibeus lituratus, principal consumer and seed disseminator of C. obtusa, has been studied using a new technique of radio telemetry and automatic data acquisition (micro-computer) in the forest. This method allowed a detailed description of the frequency of flights and feeding around the feeding sites. A. lituratus makes a large number of feeding !lights per night ( - 40) correlated with a rapid digestive transit (five minutes). This type of feeding behavior implies that certain nutrients (sugars and amino acides) should be directly assimilated._Chemical analysis of C. obtusa has shown that this fruit contains at least 19 free amino acides ( ~ 2 mg/ gm pulp, dry weight) and soluble sugars ( ~ 45 mg;gm pulp, dry weight). These characteristics of C. obtusa are discussed in terms of the coevolution of this fruit with dispersal of seeds by A. /ituratus. The pattern of seed dispersal has been studied by collectors in different biotopes. Variations in dispersal between C. obtusa and C. sciadophylla are related to both the ecology of the two plant species and to the behavior of their principal dispersal agents, bats or birds.