Cecropia (Cecropiaceae), a genus of 71 species restricted to the Neotropics (Berg & Franco-Roselli, In press), is well known as a pioneer plant abundant in light gaps and secondary vegetation in tropical rain forest. The indehicsent fruits of Cecropia are surrounded by the perianth which usually becomes fleshy and attracts many different animal dispersal agents, including birds, bats, kinkajous, marsupials, monkeys, and fish. Among the most abundant trees in secondary forests of French Guiana are two Cecropia species dispersed by bats: the primarily bat dispersed C. obtusa and the primarily bird dispersed C. sciadophylla. The fruits and seeds of these species collected directly from plants and from bat feces were studied with purpose of 1) clarifying the structure of the dispersal unit (diaspore), 2) determining what part of the infructescence is consumed by bats, and 3) providing characters useful for identifying fruits collected from bat feces. The pericarp of Cecropia is thickened and strengthened by macrosclereids, large crystals, tanniniferous cells, and an additional sclerefied layer in C. obtusa. The seed coat is thin, and, hence, the pericarp serves to protect the seed. The diaspores of species of Cecropia are fruits; thus bats and other animals disperse fruits, not seeds as erroneously reported in the literature. Bats consume the ripe part of infructescence, digest the pulp derived from the enlarged, fleshy, white-greenish perianth, and defecate the fruits. Fruits of C. obtusa and C. sciadophylla possess mucilage cells in the exocarp that are partly or entirely lost during endozoochorous dispersal. We hypothesize that the mucilage makes the fruits of Cecropia more slippery thereby facilitating their passage through the animals digestive tracts.

Key words: bat food resource, Cecropia, Cecropiaceae, French Guiana, fruit anatomy