A raindrop weighs 50 times a mosquito, so how does the lowly insect survive a collision with it? Mechanical engineer David Hu of Georgia Institute of Technology and colleagues investigated:
The team constructed what it calls a "flight arena," a 20-centimeter-high acrylic cage covered with a mesh top that allowed water in but kept the mosquitoes from escaping. In an initial round of experiments, the researchers shot jets of water into the cage to simulate raindrops falling 10 meters, the height at which they achieve their maximum velocity. Six mosquitoes placed in the cage were then filmed with a high-speed video camera that captured 4000 frames per second.
It was like a game of insect pinball. All six mosquitoes were able to recover from drop impacts without crashing to the bottom of the cage. In one typical example, a mosquito hit by a water drop tumbled a distance of 13 body lengths before separating itself from the drop and flying laterally to land on the side of the arena. To better picture what was happening, the team subjected 20 mosquitoes to drops that were falling more slowly. The videos showed that most of the collisions were glancing blows on the wings and legs rather than on the insects' bodies. The impacts caused the mosquitoes to pitch, yaw, or roll depending on where they were hit.