Washington (AFP)

Drones launching soap bubbles can be used to pollinate fruit trees, endangered by the unprecedented decline of bees, according to a Japanese study published Wednesday in the American journal iScience.

Professor at the Japan Advanced Institute of Science in Japan and author of the study, Eijiro Miyako has been working for several years on pollinating robots, but these tended to crush the flowers.

"It was very sad," he told AFP.

The scientist then had the idea of ​​using soap bubbles when playing in a park with his three-year-old son.

Miyako and Xi Yang, co-author of the study, analyzed soap bubbles under a microscope confirming that they could transport pollen grains.

Experts then tested the effects of five commercially available surfactants to make bubbles, including lauramidopropyl betaine used in the cosmetic industry for its foaming properties. It has been shown to be the best option for growing the tube that develops from each pollen grain after it is deposited on a flower.

They put the foaming solution in a bubble machine and sprayed these pollen-laden bubbles into a pear orchard. This method, at the rate of 2,000 grains of pollen per bubble, made it possible to pollinate 95% of the targeted flowers which then gave fruit.

"It sounds a bit fanciful, but the soap bubble allows effective pollination and guarantees fruit of a quality equivalent to that of conventional manual pollination," said Eijiro Miyako.

The researchers then turned their experiments to the sky, equipping a small drone with the programmed route with a soap bubble launcher.

This time the targets were fake lilies, the flowering season having passed.

Flying two meters above the ground at a speed of two meters per second, the device succeeded in reaching the targeted plastic plants with a success rate of 90%.

Mr. Miyako is currently in discussions with a company for a future commercialization of this technique.

He added, however, that the robot's accuracy could be further improved and that automated targeting of flowers could be added.

This study is the first to explore the properties of soap bubbles for transporting pollen and to consider the use of autonomous drones.

The authors of the article hope to generate renewed interest in artificial pollination methods.

© 2020 AFP