POLLINATION OF STRAWBERRY BY THE STINGLESS BEE, TRIGONA-MINANGKABAU, AND THE HONEY-BEE, APIS-MELLIFERA - AN EXPERIMENTAL-STUDY OF FERTILIZATION EFFICIENCY

To know basic information about the stingless bee, Trigona minangkabau, and the European honey bee, Apis mellifera, as pollinator of strawberry, we set three greenhouse areas: the honey bee introduced area, the stingless bee introduced area and the control area. Foraging and pollination efficiencies of the two bee species were studied comparatively. During the experimental period (10 days), the stingless bee foraged well and the nest weight did not change, though the honey bee often foraged inefficiently and the nest weight decreased by 2 kg. The average nectar volume of a flower was lower in the honey bee area (0. 02 mul) and nearly the same in the other two areas (0. 1 mul). We make a numerical model to describe pollination and fertilization process. This model shows that one visit of the honey bee pollinated 11% of achenes and one visit of the stingless bee did 4.7% on average and that 11 visits of the honey bee or 30 visits of the stingless bee are required per flower to attain normal berry (fertilization rate, 87%). In this study, the rate of deformed berries in the stingless bee area (73%) was lower than that of the control area (90%), but higher than that of the honey bee area (51%). From our numerical model, we conclude the sting less bee could pollinate strawberry as well as the honey bee if we introduced 1.8 times of bees used in this experiment.