| Title: | "Bird pollination in an angraecoid orchid on Reunion Island (Mascarene Archipelago, Indian Ocean)" |
| Author(s): | Micheneau C; Fournel J; Pailler T; |
| Address: | "UMR 53 Peuplements Vegetaux et Bio-Agresseurs en Milieu Tropical, Universite de La Reunion, 15 avenue Rene Cassin, BP 7151, 97415 Sainte Clotilde Messag Cedex 9, La Reunion, France. claire.micheneau@univ-reunion.fr" |
| ISSN/ISBN: | 0305-7364 (Print) 1095-8290 (Electronic) 0305-7364 (Linking) |
| Abstract: | "BACKGROUND AND AIMS: Although numerous angraecoid orchids in Madagascar display typical sphingophilous syndrome (i.e. white, nectariferous, long-spurred flowers, producing a strong scent at the crepuscule that is attractive to moths), three species of Angraecum in Reunion, belonging to the endemic section Hadrangis, have atypical unscented and short-spurred flowers. The aim of the study was to investigate the implication of plant-pollinator interaction on the evolution of floral morphology of these peculiar island floral forms. METHODS: The flower morphology of A. striatum (one of the three section Hadrangis species) was investigated by performing a set of floral measures, and the reproductive biology was investigated by a set of hand pollination experiments. Natural pollinators were observed by means of a digital video camera. Pollinator efficiency (pollen removal and deposition) and reproductive success (fruit set) were quantified once a week in natural field conditions during the 2005 flowering season (i.e. from January to March). KEY RESULTS: The orchid is self-compatible but requires a pollinator to achieve fruit set. Only one pollinator was observed, the endemic white-eye Zosterops borbonicus (Zosteropidae). These birds perched on inflorescences, and probed most fresh-looking flowers on each plant for nectar. Nectar was both abundant (averaging 7.7 microL) and dilute (averaging 9.7 % sugar in sucrose equivalents). Birds were mostly active between 0830 and 0930 h. Visits to plants were extremely short, lasting from 9 to 27 s. At the study site, 60.9 % of flowers had pollen removed, and 46.4 % had pollinia deposited on stigmas. The proportion of flowers that initiated a fruit averaged 20.6 % in natural conditions. CONCLUSIONS: For the first time, a bird-pollinated orchid is described from a sub-tribe that is mainly specialized for moth pollination. This study documents a morphological shift in flowers in response to pollinator adaptations in the insular context of the Mascarene Archipelago" |
| Keywords: | Animals Birds/*physiology Flowers/*anatomy & histology Orchidaceae/anatomy & histology/*physiology Pollen/*physiology Reproduction/physiology Reunion; |
| Notes: | "MedlineMicheneau, Claire Fournel, Jacques Pailler, Thierry eng Research Support, Non-U.S. Gov't England 2006/03/24 Ann Bot. 2006 Jun; 97(6):965-74. doi: 10.1093/aob/mcl056. Epub 2006 Mar 22" |
