Preference in flower visits and partitioning in pollen diets of stingless bees in an Asian tropical rain forest

摘要

Floral resource partitioning among stingless bees (Trigona, Meliponini, Apidae) in a lowland rain forest in Sarawak, Malaysia, was investigated using tree towers and walkways in a 4-year study (June 1993 to October 1996) that included a general flowering period. One hundred collections of insect visitors to flowers of varying floral location and shape representing 81 plant species were made. The tendency of 11 species of stingless bees to visit specific flowers with a particular floral location andshape was analysed by logistic regression analysis. This analysis showed that the proportion of flower visitor collections containing Trigona fuscobalteata and T. melanocephala differed according to floral location. The former was frequently collected at canopy and gap flowers, whereas the latter was most often collected at understorey flowers. The analysis also suggested that T. erythrogastra was more rarely collected at shallow flowers than at deep flowers. Analysis of the pollen diets of T. collina,T. fuscobalteata, T. melanocephala and T. melina revealed that similarity of pollen sources differed among the six permutated pairs of the four species. The lowest mean rank of similarity found was between T. fuscobalteata and T. melanocephala. This result supports the hypothesis that preference in visiting flowers in different locations leads to pollen resource partitioning.