Abstract
The plant genus Ficus is a keystone resource in tropical ecoystems. One of the unique features of this group is the modification of fruit traits in concert with various dispersers, the so-called fruit syndromes. The classic example of this is the strong phenotypic differences found between figs with bat and bird dispersers (color, size, and presentation). The ‘bird-fig’ Ficus colubrinae represents an exception to this trend since it attracts the small frugivorous bat species Ectophylla alba at night, but during the day attracts bird visitors. Here we investigate the mechanism by which this ‘bird-fig’ attracts bats despite its morphology which should appeal solely to birds. We performed feeding experiments with Ectophylla alba to assess the role of fruit scent in the detection of ripe fruits. Ectophylla alba was capable of finding ripe figs by scent alone under exclusion of other natural sensory cues. This suggests that scent is the key signal in the communication between Ectophylla alba and Ficus colubrinae. Analyses of odor bouquets from the bat- and bird-dispersal phases (i.e. day and night) differed significantly in their composition of volatiles. This indicates that an olfactory signal allows a phenotypically classic ‘bird-fig’ to attract bat dispersers at night thus to maximizing dispersal.
