Les chauves-souris frugivores de la région de Manaus et leur rôle dans la dissémination des espèces végétales

Résumé En

Fifty eight species of bats were trapped with mist-nets in the Manaus area, Amazonas, Brazil. Eighteen of them were found to be exclusively or partly frugivorous. Bats belonging to subfamilies Carollinae, Sturnirinae and Stenoderminae fed only on fruit, whereas Phyllostominae and Glossophaginae were omnivorous. Some unidentified plant material (not fruit) was also recovered from the stomachs of some Carollia brevicauda. On the other hand, four species known to be frugivorous elsewhere in tropical America (Tonatia silvicola, Trachops cirrhosus, Vampyrum spectrum and Chaeroniscus minor) were not found to eat fruit in our study area. When these actual and potential fruit-eating bats are all taken together, they represent 74-78 % of the bat community sampled between 0.5 and 2.0 m above ground (878 out of 1 474 captured individuals). If bat species living and feeding mostly in the canopy were to be taken into account, the percentage of frugivorous bats would probably be different. The frugivorous bats studied did not feed at random, but were highly selective. The fruits eaten were picked up from emergent forest trees, or from understorey plants. Fruits from trees and shrubs of secondary forest were frequently consumed, as well as those of cultivated fruit trees. The fruits selected by bats were fleshy, dull and grew away from the foliage (flagellicarpy or caulicarpy). Seed dispersal by bats is carried out either by transport of the fruit in the mouth of the animal and subsequent dropping of the kernel, or by ingestion of the fruit and subsequent defecation of the seeds. Endozoochory is shown to facilitate germination of some seeds. These data show that bats play an important (perhaps the most important) role in seed dispersal during the forest-regeneration cycle in central Amazonia, particularly for pioneer species.