LOBOVA, TATYANA A.* and SCOTT A. MORI. Institute of Systematic Botany, The New York Botanical Garden, Bronx, New York 10458-5126, USA. - Cecropia fruits as a food resource for bats in French Guiana.
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