Pollination Efficiency of Honeybees (Apis mellifera L.) and Bumblebees (Bombus terrestris L.) in Different Cultivars of Asian Pear (Pyrus pyrifolia Nakai)

Various cultivars of Asian pears (Pyrus pyrifolia Nakai) have been cultivated in Korea. Because foraging behaviors of insect pollinators for nectar and pollen determine the fruit production, we investigated comparative pollination efficiency of the honeybee (Apis mellifera L.) and bumblebee (Bombus terrestris L.) on pear cultivars, including ‘Niitaka’, ‘Gamcheonbae’, ‘Wonhwang’, ‘Whasan’, and ‘Whangkeumbae’, that are grown in Korea. The foraging rates and time spent on the flower of honeybee and bumblebee were significantly different among cultivars. The foraging rate of the honeybee was highest in the vars. Hwasan, followed by the Whangkeumbae, Manpungbae, and Niitaka; whereas that of the bumblebee was highest in the vars. Hwasan, followed by the Manpungbae, Niitaka, and Whangkeumbae. In particular, the foraging rate preference of the honeybee was 1/3 in the Niitaka, which was lower than that of the other cultivars. Honeybee spent the longest time in flower of Hwasan, followed by the Niitaka, Whangkeumbae, and Manpungbae; whereas bumblebee spent longest time in flower of Hwasan, followed by the Niitaka, Manpungbae, and Whangkeumbae. Bumblebee showed a 2.8-fold higher rate of foraging in the pollen-producing cultivars than in the non-pollen cultivars. Fruit set by the honeybee and bumblebee was similar in most of the cultivars, except in Niitaka. Fruit set by artificial pollination was more effective than that by bee pollination in the Niitaka. However, fruit set by bee pollination was similar to that by artificial pollination in other cultivars.In fruit quality from each cultivar was not different from different pollination treatment. Therefore, it is considered that the pollination method using honeybees and bumblebees is a good option instead of the general artificial pollination in various Asian pear cultivar.