Pattern of Visiting Flowers and Pollination Efficiency of Three Kinds of Bees on ‘Irwin’Mango Fruits Grown in Plastic Greenhouses

Abstract

The pollination efficiency of two species of honeybees and bumblebees (Bombus ignites) was compared for‘Irwin’mango fruits grown in plastic greenhouses. The ratio of perfect bisexual flowers of‘Irwin’mangoes exceeded 50% in the distal part of the panicles, but tended to decrease toward the proximal part. The number of staminate flowers tended to increase in the proximal part. On fine days, visiting frequency of Japanese honeybees (Apis cerana japonica) to flowers in a panicle was twice as high as that of European honeybees (A. mellifera), while no differences were noted on rainy days. The number of bumblebees that visited the flowers on rainy days was only about 15% of the number on fine days. On the other hand, the duration of foraging of European honeybees was the longest on a panicle, followed by that of Japanese honeybees and bumblebees. Japanese honeybees commonly moved from flower-to-flower, while European honeybees tended to stay on the same flower panicle. Although the foraging duratuon of European honeybees was shorter on rainy days, the effect of the weather conditions on the foraging duration in Japanese honeybees and bumblebees was not significant. No differences were detected in the number of bees leaving the hives on fine and rainy days. The seeded fruit ratio was high with all three pollinators: 71.7% for Japanese honeybees, 69.0% for European honeybees and 59.3% for bumblebees. Although a larger number of fruits weighed more than 200 g with European and Japanese honeybee pollinators, bumblebee pollinators produced many small fruits weighing less than 100 g. The results showed that both European and Japanese honeybees are effective pollinators for the production of large mango fruits.