Effects of pollination by Melipona quadrifasciata (Hymenoptera: Apidae) on tomatoes in protected culture

抄録

To evaluate the pollination efficiency of a stingless bee, Melipona quadrifasciata, individuals originating from tropical and subtropical regions of South America were examined on tomatoes (cv. Momotaro 8) cultivated in a greenhouse in summer and autumn. We compared differences in the rates of foraged flowers, pollen weights foraged from anthers, rates of fruit set of tomatoes, seed number of tomato fruits and yields of tomato fruit weight between M. quadrifasciata and the bumblebee, Bombus terrestris. When the amount of tomato pollen was sufficient, there were no differences in pollination efficiency between the stingless bee and the bumblebee; however, the rates of foraged flowers, the rate of fruit set and the yields were significantly reduced in the stingless bee compared with the bumblebee when fertile tomato pollen decreased markedly during the hottest period of the summer. During this period, the rate of flowers foraged by bumblebees did not decrease, but the rates of fruit set, the seed number and the yields of tomato fruits decreased significantly in comparison with the other periods. It is known that tomato pollen production is inhibited at high temperatures; thus, we consider that the high temperatures in the greenhouse (average daily temperature higher than 28°C) caused the extreme decrease in pollen production. These results indicate that M. quadrifasciata can be used as a suitable pollinator of tomatoes if sufficient amounts of fertile pollen are provided.