Heterostyly is a floral polymorphism consisting in the presence of two morphs in the population that differ reciprocally in the position of their sexual organs. Heterostylous species depend on visitors to produce fruits, but the efficiency of insect species as pollinators greatly varies and depends on the morph visited. The aim of the present study was to determine the effect of a single visit by the bees Apis mellifera and species of Augochloropsis on the fruit set of the distylous species Psychotria carthagenensis. After a single visit from each bee species, flowers were bagged to monitor the fruit set. Pollination effectiveness between pollinators and morphs was compared. The results of the experiments were compared with data from manual intermorph cross-pollination using the G test. There were no significant differences in the fruit set between treatments (insect visit and cross-pollination), and between flowers visited by Augochloropsis spp. and flowers visited by A. mellifera. Our results suggest that pollination effectiveness of the studied bees was not related to floral morph, and that both exotic and native bees showed similar performances on the fruit set of P. carthagenensis.
Bee pollination; heterostyly; honeybees; pollination effectiveness; reproductive success
