You've probably heard that honey bees — a domesticated species, Apis mellifera, that farmers rely upon to pollinate crops — have been dying off in disturbing numbers in recent years, with entire hive populations disappearing in a phenomenon known as Colony Collapse Disorder.
But there are nearly 4,000 species of wild bees in North America, and a lot of them are in trouble as well. A study published in the journal Science in 2013, for example, found that half of the bee species found in one Illinois forest in the late 1800s have vanished.
But even as there's a looming bee-pocalyse in the biological world, researchers have been making great strides in developing robotic bees that have some of the abilities of the actual insects — as well as some that surpass actual bees. Eventually, such tiny robots could serve a variety of uses, ranging from military surveillance to aiding search-and-rescue missions during natural disasters. It's even conceivable that in a pinch, they could pollinate plants.
At Harvard University, researchers have been working for more than a decade to develop the RoboBee, a tiny machine that's half the size of a paper clip and weighs less than a tenth of a gram. Engineering professor Robert J. Wood, founder of the Harvard Microrobotics Laboratory, has copied the structure of actual insect wings to develop artificial ones, made from a polymer membrane fastened to carbon-fiber supports. The RoboBee flaps its wings 120 times per second, in the same manner that an actual bee does to hover and fly.
In 2013, the researchers managed to get the RoboBee to fly for the first time. But now it can do more than that. At the recent International Conference on Intelligent Robots and Systems in Hamburg, Germany, Harvard researchers presented a paper explaining how the RoboBee can land—or rather, dive--into water. It then converts itself into an extremely tiny version of a scuba diver, flapping its wings slowly for propulsion. (Check out the video at the top of this article.)
"The interesting aspect is the observation that the fluid mechanics of the RoboBee wings are similar for high-frequency flapping in air and low-frequency flapping in water," says Robert Wood via email. "Simply by changing the frequency upon entering water, a similar wing motion is achieved and similar forces are generated."
While the swimming RoboBee's value primarily is in contributing to knowledge about fluid mechanics, Wood said the aquatic capability someday might enable robotic bees to be used for water-quality monitoring.
According to a recent Nature article, one big challenge of creating functioning robotic bees is powering them. The Harvard scientists reportedly have made advances in battery storage, electronics and motor technology that now enables a RoboBee to stay aloft for a few minutes at a time. Eventually, though, future generations of robotic bees may take far longer flights, equipped with tiny radio transmitters and global positioning systems to guide them.
Harvard's Wyss Institute for Biologically Inspired Engineering, which is involved in the RoboBee project, notes on its website that the artificial insects someday might even be pressed into service to pollinate crops. That said, researchers estimate that it will be at least another 20 years before robotic bees could act as replacements for biological ones, and then only as a stop-gap measure.
"We would be much better served finding and solving the root causes of colony collapse disorder, as opposed to creating a robotic solution to replace pollinators," says Wood.
And there's another major obstacle: One single beehive can contain 25,000 insects. That's a whole lot of RoboBees we'd need to build.