Bees are major pollinators responsible for sustainable agriculture and the associated economic factors such as maintaining adequate food supply. However, due to climate change and habitat loss, they, as well as other pollinator species, are experiencing declines in population, which is assumed to affect 3 to 8 percent of global crop production. The cause of a mysterious phenomenon of beehives’ disappearance, or colony collapse order, is still unknown, although many theories have been offering explanations such as diseases and other disorientations. In consideration of the bee’s contribution to the ecosystem and food supply, concern over its population decline is growing, and the significance of developing a substitution cannot be stressed enough.
Since farmers rely heavily on bees for pollination in the status quo, many researchers are striving to find novel technologies that are capable of replacing natural pollinators. There is always the option of direct pollination using feather brushes, but roboticists desire to invent clever ways to provide convenience and greater consistency in pollination. Most of these methods involve drones, one of the earliest ones being introduced by Eijio Miyako, a chemist in AIST. Remodeled after the hairy features of a bee, horse hairs are attached to the drone using a sticky ionic gel. The drone functions as a robotic replacement for bees, able to transport pollen from one flower to another. However, it is indeed not a perfect solution since the propellers often damage the flowers, preventing them from growing healthy fruits. Therefore, Miyako discovered another technique that the drones could incorporate: bubble guns. Without making significant changes, they can be used to blow bubbles with pollen grains rather than just the bubbles themselves.
Photo Credits: Eijiro Miyako
Caption: Delivering pollen to Campanula flowers with bubbles
Inspired during a date with his son, he realized that pollen carried by bubbles is less likely to be damaged or wasted by failing to land on the pistil. After learning about the soap bubble’s unique, ideal features, Miyako developed a suitable bubble solution by randomly selecting five different surfactants — substances that reduce the surface tension of a liquid — and detecting one that can produce the most bubbles in one trigger of a bubble gun. Lauramidopropyl betaine was the best surfactant as a foaming agent, forming the most bubbles and showing a high success rate in germination and pollen tube elongation, unharming, or even helping pollen activity. Miyaki then tested the results again with different concentrations of surfactants and pollen, finding that a high concentration of surfactant and a lower number of pollen grains are most suitable for bubble formation; pollen grains are discovered to have water-insoluble agglomeration that prevents producing steady membranes.
After finding the optimal surfactant and pollen grain concentrations, Miyaki controlled pH and added other chemicals such as boron, calcium, magnesium, and potassium to promote better germination; calcium binds to the pectate carboxyl groups on the pollen wall, greatly increasing the growth of pollen, and other chemicals’ roles are to assist calcium. To stabilize the bubbles, Miyaki also included gelatin and hydroxypropyl methylcellulose. With the perfect bubble solution containing a stable liquid membrane and large surface area, Miyaki was finally satisfied and confident that the bubble would not burst while transferring the pollen. In the actual experiment, the bubbles showed high performance, hitting 90 percent of the flowers that successfully pollinated.
At this stage of development, there are certainly some components that could be improved. For example, if a plant identifying robot can be added, the drone would be able to narrow down the scope and perfectly shoot the bubble in the right direction. Additionally, this technology is vulnerable to the surrounding environment, so it has limits in its application and might not be suitable for a large scale project. However, carrying pollen grains with bubbles provides numerous benefits that transcend other delivery methods. First, as aforementioned, it reduces the risk of damaging the pollen and the flower by safely landing on the pistil. Second, the bubble’s stickiness helps pollen easily attach to the flower, decreasing the number of pollen grains wasted. Finally, since pollen grains can be scattered uncontrollably, the use of bubbles help contain the pollen grains and directly target them toward the flowers. Miyaki well-incorporated his idea onto the unique characteristics of soap bubbles that include flexibility and lightweight so that its necessary traits can be conserved and lacking properties can be refined. With these successes, there seems to be a great chance of this technology to be implemented and applied to our society, possibly substituting the growing absence of pollinators in the future.
Works Cited
Schaft, Peter van der. “Pollination Drones Seen as Assistants for Ailing Bees.” Robotics Business Review, 28 Mar. 2018, www.roboticsbusinessreview.com/agriculture/pollination-drones-assist-ailing-bees/.
Prisco, Jacopo. “Researchers Use Drone to Pollinate Flower.” CNN, Cable News Network, 9 Mar. 2017, edition.cnn.com/2017/03/09/world/artificial-pollinator-japan/index.html.
Yang, Xi, and Eijiro Miyako. “Soap Bubble Pollination.” IScience, Elsevier, 17 June 2020, www.sciencedirect.com/science/article/pii/S2589004220303734.
Giaimo, Cara. “Blowing Bubbles to Pollinate Flowers.” The New York Times, The New York Times, 17 June 2020, www.nytimes.com/2020/06/17/science/bubbles-pollinating-bees.html.
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