Bees and other pollinators, such as butterflies, are essential for farmers who grow flowers like fruit and almond orchards, but with bee populations suffering in the past decade due to a variety of factors, an innovative researcher in Japan may have found the solution perfect - the idea came to him while he was in the park blowing soap bubbles with his son.
Eijiro Miyako, an associate professor at Japan's Advanced Institute of Science and Technology, successfully used soap bubbles to pollinate a pear orchard, delivering pollen grains to the most delicately targeted flowers using a drone.
The whimsical technique would be much cheaper and more effective than other types of manual pollination, when used in conjunction with robotic or drone delivery methods.
The study, published in Nomi, Japan, on June 17 in the journal iScience, presents a low-tech complement to robotic pollination technology designed to complement the work of missing bees.
"It sounds like fantasy, but the functional soap bubble allows for effective pollination and ensures that the quality of the fruit is the same as that of conventional manual pollination," wrote Miyako, senior author.
"Soap bubbles have innovative potential and unique properties, such as the efficient and convenient delivery of pollen grains to targeted flowers and high flexibility to avoid damaging them".
Miyako and his colleagues had previously published a study in the journal Chem, in which they used a small toy drone to pollinate blooming flowers. But even though the drone was only an inch long, the researchers struggled to prevent it destroying the flowers when it collided with them.
While looking for a more ecological artificial pollination technique, Miyako spent a day in the park blowing bubbles with his son. When one of the bubbles crashed into his son's face - a predictably injury-free accident - Miyako found his inspiration.
After confirming by optical microscopy that soap bubbles could, in fact, transport pollen grains, Miyako and Xi Yang, his co-author of the study, tested the effects of five commercially available surfactants on pollen activity and bubble formation . The neutralized surfactant lauramidopropyl betaine (A-20AB) beat its competitors, facilitating the best pollen germination and the growth of the tube that develops each pollen grain after being deposited in a flower.
Based on a laboratory analysis of the most effective soap concentrations, the researchers tested the performance of pear pollen grains in a 0.4% A-20AB soap bubble solution at an optimized pH and added calcium and other ions to support germination. After three hours of pollination, pollen activity mediated through soap bubbles, remaining stable, while other methods, such as pollination through powder or solution, became less
Miyako and Yang loaded the solution into a bubble gun and launched pollen-laden bubbles into a pear orchard, discovering that the technique distributed pollen grains (about 2,000 per bubble) to the flowers they targeted, producing fruits that demonstrated the pollination success.
Finally, the researchers carried a standalone GPS-controlled drone, which they used to direct soap bubbles at fake lilies (since the flowers were no longer in bloom) at a height of two meters, reaching their targets at a success rate of 90% when the machine is moved at a speed of two meters per second.
Although this approach to pollination looks promising, more techniques are still needed to improve its accuracy. In addition, with soap bubbles, the climate is essential - raindrops can wash bubbles containing pollen flowers, while strong winds can deflect them.
Next, Miyako and colleagues plan to address the issue of waste generated by the prototype of the artificial pollinator, since most bubbles are still unable to land on their target flowers.