Meadville Tribune

Outdoors

June 6, 2012

Bad news: Raindrops don't swat down mosquitoes

Findings could aid design of tiny flying robots

(Continued)

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.

But even when the mosquitoes took a direct hit, they still recovered after falling no more than about 20 body lengths. Hu and his colleagues hypothesized that due to the insects' low mass — about 2 milligrams, whereas a raindrop can be up to 100 milligrams — the raindrop loses very little speed and momentum upon encountering the mosquito and thus imparts very little actual force to it. To test this hypothesis, the team constructed insect "mimics" made of small Styrofoam spheres the same weight and size as the mosquitoes. When the researchers released the spheres into the arena, they were momentarily suspended in mid-air as water droplets collided with them from above.

Text Only
Outdoors
Business Marquee
AP Video
Raw: 2 Shells Hit Fuel Tank at Gaza Power Plant Raw: Massive Explosions From Airstrikes in Gaza Giant Ketchup Bottle Water Tower Up for Sale Easier Nuclear Construction Promises Fall Short Kerry: Humanitarian Cease-fire Efforts Continue Raw: Corruption Trial Begins for Former Va Gov. The Carbon Trap: US Exports Global Warming UN Security Council Calls for Gaza Cease-fire Traditional African Dishes Teach Healthy Eating 13 Struck by Lightning on Calif. Beach Baseball Hall of Famers Inducted Israel, Hamas Trade Fire Despite Truce in Gaza Italy's Nibali Set to Win First Tour De France Raw: Shipwrecked Concordia Completes Last Voyage Raw: Sea Turtle Hatchlings Emerge From Nest Raw: Massive Dust Storm Covers Phoenix 12-hour Cease-fire in Gaza Fighting Begins Raw: Bolivian Dancers Attempt to Break Record Raw: Israel, Palestine Supporters Rally in US Raw: Air Algerie Flight 5017 Wreckage
Hyperlocal Search
Premier Guide
Find a business

Walking Fingers
Maps, Menus, Store hours, Coupons, and more...
Premier Guide
Stocks