Pollination in Australian Orchids: a Critical-Assessment of the Literature 1882-1992

Abstract

A century of pollination studies of Australian orchids is reviewed. Descriptions of pollination events and conclusions about pollination status are inadequate in many reports. In this review criteria for establishing 'confirmed', 'probable' and 'suggested' pollinator status are defined and recommended. When applied to 153 published pollination reports there are 24 terrestrial species with 'confirmed' pollinators and a further 47 species with 'probable' pollinators. The major syndromes confirmed are wasp pollination by pseudocopulation (15 species) and the bee pollination syndrome of food mimicry (5 species). Nectar and pollen reward systems operate in a small number of species. Eleven epiphytic species have 'confirmed' pollinators, and four have 'probable' pollinators. Thirteen of the fourteen confirmed reports of epiphyte pollination describe social or solitary bees, mainly of the genus Trigona, apparently attracted by floral display and intense fragrance, which may constitute a chemical reward system. Dendrobium is the main epiphytic genus with confirmed pollinators.