Trophic structure of a neotropical frugivore community: is there competition between birds and bats?

Abstract

Dietary overlap and competition between frugivorous birds and bats in the Neotropics have been presumed to be low, but comparative data have been lacking. We determined the diets of volant frugivores in an early successional patch of Costa Rican wet forest over a one month period. Ordination of the diet matrix by Reciprocal Averaging revealed that birds and bats tend to feed on different sets of fruits and that diets differed more among bat species than among bird species. However, there was overlap between Scarlet-rumped Tanagers and three Carollia bat species on fruits of several Piper species which comprised most of the diet of these bats. Day/night exclosure experiments on P. friedrichsthalli treetlets provided evidence that birds deplete the amount of ripe fruit available to bats. These results indicate that distantly related taxa may overlap in diet and compete for fruit, despite the apparent adaptation of animal-dispersed plant species for dispersal by particular animal taxa.

A dieta dos morcegos frugívoros (Mammalia, Chiroptera, Phyllostomidae) de um pequeno remanescente de Floresta Estacionai Semidecidual do sul do Brasil

“…), resultando em uma disponibilidade "con stante" de frutos deste genero ao longo de todo 0 ano, 0 que poderia permitir tal especializa9ao como discutido para Carollia perspicillata em rela9ao a Piper. BONACCORSO (1979), PALMEIRIM et al (1989) RBIS et at. (1996) tam bern encontraram sementes de Solanum (alem de Ficus, Piper e Cecropia) nas fezes dos indivfduos capturados desta especie.…”

“…Na Costa Rica, tres especies de Carollia alimentam-se basicamente de Piper spp. (FLEMING 1985;PALMEIRIM et at. 1989).…”

Observations on the Role of Frugivorous Bats as Seed Dispersers in Costa Rican Secondary Humid Forests

“…Germination of Piper seeds varied between 53% and 89% of their seeds in this study ;Fleming (1988) and Palmeirim et al (1989) reported less germination from seeds defecated by Carollia bats. The reason for this difference is unknown.…”

“…For each seed sample, seeds from defecated, regurgitated and control treatments were placed in petri dishes (9 cm diameter) with moistened humid filter paper (Lieberman et al, 1979;Fleming et al, 1985;Palmeirim et al, 1989). Seeds weighing more than 2 g were placed in plastic pans (30 × 20 cm) with sterilized earth the day following its collection, with a similar number of seeds in treatments and controls.…”

“…Seeds weighing more than 2 g were placed in plastic pans (30 × 20 cm) with sterilized earth the day following its collection, with a similar number of seeds in treatments and controls. Petri dishes and plastic pans were put in the environmental control laboratory at LSBR, with constant environment temperature and low indirect light Fleming et al, 1985;Palmeirim et al, 1989). Treatments were moistened with distilled water when necessary.…”