In tropical forests, animal-mediated seed dispersal is a critical ecological process contributing to the reproductive success of plants and determining plant distributions and forest composition. Piper is one of the largest genera of flowering plants, containing approximately 1,000 species. The primary dispersers of Piper fruits in Neotropical forests are a genus of bats in the family Phyllostomidae (Carollia spp.), which depend on the fruit as a year-round staple in their diet. At La Selva Biological Station in Costa Rica, three species of Carollia are present: C. castanea, C. perspicillata, and C. sowelli. Within a genus of closely-related species, resource partitioning would be expected for coexistence. The main objective of this study was to determine whether these three species of bats avoid competition by specializing on different species ofPiper. First, we used dietary analysis of seeds in Carollia fecal samples to examine how dietary composition varied among three Carollia species. Second, we used choice experiments with bats in flight cages to determine if the three Carolliaspecies differ in Piper species preference.
Results/Conclusions
All three species consumed primarily Piper, but our results indicated that Carollia castanea exhibits a stronger reliance on Piper species, whereas the other two more often subsidize their diets with other plant species. In comparisons of the relative consumption of different species within the genus Piper,we found no differences among the three Carollia species—all relied heavily on P. sancti-felicis (seeds found in ~50% of all fecal samples) as well as four other common Piper at the site. Our results also showed no significant difference in Piper feeding preference between Carollia species. All three species of Carollias howed relatively similar feeding preferences with a reduced preference for two species (P. peltatum and P. silvivagum) compared to P. sancti-felicis. Coexistence theory suggests that different species sharing the same niche cannot cohabitate without resource partitioning. However, all three species of Carollia appear to compete for the same resources, implying other mechanisms, such as different foraging habits, allow three separate species of Carollia to coexist.