Pollination mechanism in southern Brazilian orchids which are exclusively or mainly pollinated by halictid bees

The pollination process is documented in three sympatric orchids found in Curitiba, Parana State, southern Brazil. In Campylocentrum aromaticum (Epidendroideae: Angraeciinae) and Prescottia densiflora (Spiranthoideae: Prescotiinae) halictid bees act as main pollinators with minor contributions from other insects, such as Syrphid flies. Because of the pollinarium and column structure in Cyclopogon diversifolius. (Spiranthoideae, Spiranthinae), halictid bees are the only insects capable of performing pollination. In the three studied species pollinarium removal and deposition are achieved by interaction between the column and bee's mouth parts. Morphological and ecological flower features in agreement with this pollination mode are discussed and pollination by halictid bees is suggested to occur in a number of South American orchids.2174167110111