Bat Pollination of Weberocereus tunilla, an Epiphytic Rain Forest Cactus with Functional Flagelliflory

Abstract

We studied the pollination of the epiphytic cactus Weberocereus tunilla (Weber) Britton and Rose at the La Selva Biological Station in the Atlantic lowland rain forest of Costa Rica. The large, night-blooming, unpleasantly-smelling flowers were suspended on elongated main stems that hang down as much as 2 m below canopy tree branches, resulting in a unique form of flagelliflory. The only visitors to flowers were three species of glossophagine bats: Glossophaga commissarisi, Hylonycteris underwoodi and Lichonycteris obscura. Patterns of nectar secretion and concentration were found to be typical for bat-pollinated flowers. Flowering phenology and the occurrence of pollen on bats were recorded during a 1-yr period. Preliminary observations suggest that at least two other Costa Rican species of Weberocereus, W. biolleyi and W. trichophorus and possibly other species of the tribe Hylocereeae, are also pollinated by glossophagine bats.

Key words

Cactaceae - Chiroptera - flagelliflory - Glossophaginae - Glossophaga commissarisi - Hylonycteris underwoodi - Phyllostomidae - pollination - rain forest - Weberocereus tunilla