Micheneau, Claire , Carlsward, Barbara, S. , Fay, Michael F. , Pailler, Thierry , Chase, Mark W. .
Implications of plant-pollinator interactions in floral trait evolution: a case study from subtribe Angraecinae (Vandeae, Orchidaceae) on Reunion Island (Mascarene Archipelago, Indian Ocean).
THE Mascarene Archipelago consists of three oceanic islands Reunion, Mauritius, and Rodrigues, situated in the southern Indian Ocean 800–1000 km east of Madagascar. Reunion is the youngest island of the archipelago, presenting a wide range of habitats and a rich orchid flora of approximately 130 species. With about 50 species in seven genera, Angraecinae represent the most important orchid group. The Old World angraecoid orchids are famous for their spectacular specialized hawkmoth pollination systems. Since the time of Darwin, however, few studies focused on either phylogenetic relationships or reproductive biology have been conducted for the subtribe. We investigated systematics (plastid DNA sequencing) and reproductive biology (field investigations) of Mascarene angraecoid orchids. Angraecinae and the large genus Angraecum as currently circumscribed were not monophyletic. Whereas most of species are probably pollinated by small moths, pollination biology studies conducted on endemic species from Reunion highlighted two different cases: (1) autonomous self-pollination of long-spurred species and (2) bird pollination (by Zosterops borbonicus, Zosteropidae) of species belonging to Angraecum sect. Hadrangis. This study illustrates two different evolutionary reproductive strategies of closely related species from Angraecinae linked to the insular context of Reunion Island. We suggest that the lack of highly specialized sphingid pollinators in the Mascarenes has been the major driving force for the unique adaptations of these endemic species.
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1 - Université de La Réunion, Peuplements Végétaux et Bioagresseurs en Milieu Tropical, 15, avenue René Cassin, Sainte Clodilde Messag cedex 9, La Réunion, 97415, France
2 - Eastern Illinois University, Department of Biological Sciences, 600 Lincoln Ave, Charleston, Illinois, 61920-3099, USA
3 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Molecular Systematics Section, Richmond, Surrey, TW9 3DS, United Kingdom
4 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, Surrey, TW9 3AB, United Kingdom
floral trait evolution
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 31st, 2006
Time: 2:30 PM