Abstract
Background: Dioecious plants generally display sexual dimorphism in male and female floral traits resulting in differential pollinator attraction. Consequently, the partitioning of floral visitors between male and female flowers and their timing of visits to both sexes is of critical importance to ensure plant's reproductive success. Palm inflorescences are visited by abundant and diverse insect communities, yet the temporal patterns of insect visits on both sexes remain poorly known.Methods: We characterized the composition of a community of flower-visiting arthropods associated with the dioecious ivory palm (Phytelephas aequatorialis, Spruce) in a pre-montane forest of Ecuador. We monitored the temporal variations in insect visits along the flowering of 12 inflorescences (8 female and 4 male) using interception traps recovered every 4-hours.Results: We report 59 morphospecies in the arthropod community, dominated by three beetle families: Staphylinidae, Nitidulidae and Curculionidae. Male inflorescences were more abundantly visited than female, but visitors of the latter were taxonomically more diverse. Among the 16 pollinator candidates identified, 9 visited both inflorescence sexes synchronously at dusk /night whereas the others did so asynchronously during the day.Conclusion: Our study provides new insights into the pollination mechanism of P. aequatorialis. We found evidence of differential pollinator attraction between floral sexes, which may be explained by the sexual dimorphism of both flowers. Synchronicity in dusk/night visits of both inflorescence sexes suggests a sexual synchronization of the signal used to attract pollinators.