Scientists Discover How Mosquitoes Survive Collisions With Raindrops

Posted on June 4, 2012

Mosquito Raindrop

Scientists conducted an experiment to determine how insects survive impacts with falling raindrops. An individual raindrop can weigh more than 50 times a mosquito. High-speed videography of mosquito-raindrop impacts revealed a mechanism for survival: a mosquito's strong exoskeleton and low mass renders it impervious to falling drops. The mosquito's low mass causes raindrops to lose little momentum upon impact and so impart correspondingly low forces to the mosquitoes.

The researchers, led by Georgia Tech Assistant Professor of Mechanical Engineering David Hu and his doctoral student Andrew Dickerson, used a water jet to simulate rain stream velocity and observed six mosquitoes flying into the stream. All the mosquitoes survived the collision.

Hu says, "The collision force must equal the resistance applied by the insect. Mosquitoes don't resist at all, but simply go with the flow. To survive, the mosquito must eventually separate from the front of the drop. The mosquito accomplishes this by using its long legs and wings, whose drag forces act to rotate the mosquito off the point of contact. This is necessary, otherwise the mosquito will be thrown into the ground at the speed of a falling raindrop."

Dickerson says, "The most surprising part of this project was seeing the robustness this small flyer has in the rain. If you were to scale up the impact to human size, we would not survive. It would be like standing in the road and getting hit by a car."

Take a look:

The research was published here in PNAS.

Photo: Georgia Tech