Institute for Agro-Environmental Sciences, NARO

Wild pollinators are known to be useful in the cultivation of fruit trees and fruit vegetables that require pollination. However, there remained many unsolved points in the actual situation. National Agriculture and Food Research Organization (NARO) has developed a survey manual to actively utilize wild pollinating insects and has demonstrated that Bombus ardens ardens, a wild bumblebee species, contributes significantly for pollinating persimmon nationwide. By grasping the contribution of wild pollinating insects in the field, the number of hives of the European honeybee Apis mellifera, which has been introduced as pollinating insects, can be optimized for each region, enabling labor-saving cultivation.

Overview

In the cultivation of fruit trees and fruit vegetables that require pollination, artificial pollination and honeybee hives are being introduced to stabilize production. On the other hand, wild insects are also known to be useful for pollination. However, as many of the details are unclear, they have not been fully utilized. In March 2022, NARO developed a survey method and published as "Enhanced Revision of the Pollinating Insect Survey Manual to Help Pollinate Fruit Trees and Fruit Vegetables," which is available to producers. Through a series of surveys and studies, the pollinating insect fauna of persimmon nationwide was revealed for the first time, and the role played by wild bees was elucidated.

In persimmon, pollen carried from male flowers is transferred to female ones, resulting in the formation of seeds and an increase in fruit set. Therefore, the European honeybee Apis mellifera is often introduced as a pollinator to stabilize fruit set in persimmon cultivation. It was known that wild pollinators also visit persimmon, but the nationwide survey has never been performed.

NARO, in collaboration with Shimane Agricultural Technology Center and Forest Research and Management Organization, has conducted a survey regarding the flower visiting insects of persimmon from the Tohoku region to the Kyushu region, and clarified that Bombus ardens ardens, a wild bumblebee, is a major visiting flower insect in addition to A. mellifera, a domestic insect. The fruit set of 'Fuyu', a major sweet persimmon variety, has been greatly improved when B. ardens ardens visits female flowers even once, and has been further enhanced by several visits. Since the numbers of pollen grains attached to the stigmas by both species at one visit were almost equal, it was found that multiple visits by these bees were effective for stable fruit set of 'Fuyu'.

In the future, by using the manual to ascertain the flower visits by wild pollinating insects in individual persimmon gardens, the number of hives of A. mellifera to be introduced in each region can be optimized, and labor-saving cultivation using wild pollinating insects such as B. ardens ardens can be achieved.

Bombus ardens ardens visiting Persimmon Female Flower

Reference Information

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