Diverse pollination systems of the twin-spurred orchid genus Satyrium in African grasslands

作者：Johnson Steven D^*; Peter Craig I; Ellis Allan G; Boberg Elin; Botes Christo; van der Niet Timotheues

来源：Plant Systematics and Evolution, 2011, 292(1-2): 95-103.

DOI：10.1007/s00606-010-0411-1

• Bird pollination
• Floral syndromes
• Flora of southern Africa
• Functional morphology
• Nectar sugar composition
• Nyika Plateau
• Pollinaria
• Pollination success
• Rostellum

The large terrestrial orchid genus Satyrium underwent evolutionary radiations in the Cape floral region and the grasslands of southern and eastern Africa. These radiations were accompanied by tremendous diversification of the unusual twin-spurred flowers that characterize the genus, but pollination data required to interpret these patterns of floral evolution have been lacking for grassland species in the genus. Here we document pollinators, nectar properties, and levels of pollination success for 11 grassland Satyrium species in southern and south-central Africa. Pollinators of these species include bees, beetles, butterflies, hawkmoths, noctuid moths, long-proboscid flies, and sunbirds. Most species appear to be specialized for pollination by one functional pollinator group. Long-proboscid fly pollination systems are reported for the first time in Satyrium (in S. macrophyllum and a high-altitude form of S. neglectum). Floral morphology, especially spur length and rostellum structure, differs markedly among plants with different pollinators, while nectar volume, concentration, and sugar composition are fairly uniform across species. Most taxa exhibited high levels of pollination success (>50% of flowers pollinated), a trend that can be attributed to the presence of nectar in the twin spurs.

• 出版日期2011-3