It is controversial the role played by Meliponina bees in the pollination of mass flowering trees with small generalized flowers (FMPG), very common group of trees in the tropical forest canopy. The species richness and relative abundance of flower visiting insects of the mass flowering tree Stryphnodendron pulcherrimum were measured to test the hypothesis of tight ecological association between these generalist bees and FMPG and to evaluate the effect of this relationship upon the reproductive success variation among tree crowns. The flower visiting insects were sampled on 10 flowering tree crowns at the Atlantic Rainforest in southern Bahia. Altogether, 553 visiting insects were collected during the flowering period of S. pulcherrimum: 293 (52%) Meliponina bees out of 438 bees (79.4%). All tree crowns were visited by Meliponina, with the proportion of these bees ranging from 27% to 87%. The tight ecological association between FMPG trees and Meliponina bees is supported by the observed pattern of spatial relationship. Both the relationship between variation of fruit set among tree crowns and species richness (r = 0.3579; P = 0.3098) or relative abundance (r = 0.3070; P = 0.3881) of Meliponina were not statistically significant. Likely a threshold of minimum relative abundance combined with the absolute abundance of these bees explain the fruit set variation among tree crowns of S. pulcherrimum, even by self-pollination. We tested this assumption with a preliminary analysis of Melipona bee genera distribution among the tree crowns.
Stingless bee; pollination; geitonogamy; canopy
