XVI International Botanical Congess

Pollination of orchids by bees appears to be poorly represented in southern Africa relative to other temperate orchid floras. The relatively small number of bee-pollinated orchids (< 1/3 of the flora) can be attributed to the diversity of other orchid-pollinating insects, especially long-tongued flies, butterflies and moths. Most bee-pollinated orchid species provide a food reward of some kind, but a few are generalized food mimics. In Disa the largest orchid genus, bee pollination has evolved at least five times and includes both rewarding and deceptive species. Many of the bee-pollinated orchids produce a non-volatile oil as the pollinator reward. This syndrome is unknown in other temperate orchid floras and can be attributed to the exploitation of a pre-existing relationship between oil-secreting scrophs and Rediviva bees.