Summer’s here. Along with barbecues, beach excursions and baseball games, that also means the arrival of a particularly unwelcome visitor—the mosquito.
But as we cringe, imagining the hordes of mosquitoes that will bother us shortly, we’ve also got to hand it to them—they’re remarkable hardy creatures, resisting all manner of sprays, repellents, candles and anything else we throw at them. And one of their most amazing abilities is that they can remain in flight in the midst of one of nature’s own attacks: a falling raindrop.
For a mosquito, getting hit with a raindrop is the equivalent of a human getting hit by a 3 ton object—something roughly the size of a pickup truck. An individual raindrop is about 50 times the mass of a mosquito, and the drops fall at speeds as fast as 22 miles per hour. Yet the tiny insects are able to survive countless collisions during the course of a storm, when these truck-sized hazards are plummeting all around them.
How do they do it? According to a study published earlier this week in the Proceedings of the National Academy of Sciences, it is the mosquito’s tiny size—along with a zen-like approach of passive resistance—that allows it to stay in flight despite these massive collisions.
Mosquitoes, it turns out, combine an extremely strong exoskeleton with a minuscule mass to minimize the force of each raindrop when it hits. The fact that they are so much lighter than the raindrops means that the drops lose very little momentum when they collide with the mosquitoes, which translates into very little force expelled onto the insect.
Additionally, instead of standing strong against the drops, or even trying to dodge them, mosquitoes simply go with the flow. ”As the raindrop falls, rather than resisting the raindrop, they basically join together kind of like a stowaway,” David Hu, an engineer at Georgia Tech and an author of the study, told NPR. “So as a result they get very, very little force.” The impact of the raindrop can knock the mosquito partly off course, but it doesn’t harm the insect nearly as much as it would if it were absorbed as a direct hit.
Moments after the mosquitoes latch on to the raindrops, they use their wings and long legs as miniature sails to lift themselves off the falling droplets before they crash into the ground, as shown in the video below. The main danger, the researchers found, is when mosquitoes are hit by raindrops when they are already close to the ground, because if they can’t dislodge in time, they’ll be slammed into the earth at the same speed as the falling drop.
