Floral Biology of Rhipsalis paradoxa (Cactaceae: Cactoideae) in Semideciduous Mesophyll Forest (Atlantic Forest) at Serra do Japi, Jundiaí-SP.

The aim of this study was to investigate the floral biology and to determine the main floral visitors and potential pollinators of Rhipsalis paradoxa (Cactaceae). This study was conducted in an Environmental Protection Area in the Serra do Japi, Jundiai-SP. The R. paradoxa flowering season comprehended the months of September and October of 2001. The principal floral visitors were Apis melifera, Billbergia brasiliensis, Melipona quadrifasciata, Melipona bicolor and Trigona sp., all these bees belonging to Apidae family, thus this species consists in a melittophilous cactus. All floral visitors are potential pollinators. B. brasiliensis was considered the main pollinator, since it is a very common species, displays legitimate visits and promotes xenogamy when they move between distant individuals in the population. A. mellifera, M. bicolor and M. quadrifasciata are secondary pollinators, presenting lower visitation rates and short distance flights, promoting mainly self-pollinations and low gene flow within the population of R. paradoxa. Trigona sp., was the most common species and remained longer time in the flowers, however, this bee visited essentially flowers within the same plant favoring basically the geitonogamy, for this reason was considered only as a secondary pollinator. The conservation of the main pollinators of R. paradoxa is crucial for conservation of this cactus species that depend exclusively on bee pollination for its reproductive success.