Mosquito

By Mariel Emrich, Columbia Grammar and Preparatory School

Mosquitoes are as adept at flying in rainstorms as under clear skies. But how is that possible? Wouldn’t rain crush a mosquito to the ground since mosquitoes weigh 50 times less than raindrops?

David Hu, an assistant professor of mechanical engineering and biology at the Georgia Institute of Technology, and his graduate research assistant Andrew Dickerson have found that while mosquitoes do get hit by raindrops, they don’t get crushed by them.

Hu discussed their research in a talk at November's APS Division of Fluid Dynamics Meeting that was entitled “How Mosquitoes Fly in the Rain”.

The researchers measured the impact forces of raindrops on both regular mosquitoes and custom-built mosquito mimics. The mimics were made from small Styrofoam spheres of mosquito-like size and mass. They used high-speed video to capture images of the mosquitoes getting hit with raindrops.

Since the bugs fly so slowly (a maximum of 1 meter per second) compared to the drops (which fall between 5 to 9 meters per second), the mosquitoes cannot react quickly enough for avoidance, and most likely cannot sense the imminent collision.

“Under low-wind conditions, the insects fly slowly enough that frontal impacts are infrequent, similar to us running in the rain. Instead, transverse impacts on the body and wings dominate,” explained Dickerson in a a statement.

Picture a giant boulder falling on a human who was also falling through space. Unless the human gets hit straight on, the boulder will probably push us over to the side -- just like raindrops do to mosquitoes. The mosquitoes will not get crushed by rain, but instead may get rotated

The mosquitoes low mass, speed, and inertia mean that they are not damaged by collisions with raindrops. The drops don’t splash on the bugs, instead they may push the mosquitoes to the side. Additionally, depending on the way that the raindrop hits the mosquito, the drop may bounce off.

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Mariel is currently a sophomore at Columbia Grammar and Preparatory School in New York City. She loves learning about science and particularly enjoys genetics, cancer research, radiology, and forensics.