Mosquitos fail at flight in heavy fog

Nov 19, 2012

Mosquitos have the remarkable ability to fly in clear skies as well as in rain, shrugging off impacts from raindrops more than 50 times their body mass. But just like modern aircraft, mosquitos also are grounded when the fog thickens. Researchers from the Georgia Institute of Technology present their findings at the 65th meeting of the American Physical Society's (APS) Division of Fluid Dynamics, Nov. 18 - 20, in San Diego, Calif.

"Raindrop and fog impacts affect mosquitoes quite differently," said Georgia Tech researcher Andrew Dickerson. "From a mosquito's perspective, a falling raindrop is like us being struck by a small car. A fog particle – weighing 20 million times less than a mosquito – is like being struck by a crumb. Thus, fog is to a mosquito as rain is to a human."

On average during a , mosquitos get struck by a drop once every 20 seconds, but fog particles surround the mosquito continuously as it flies. A mosquito's interaction with a is therefore brief, but the interaction with fog particles is continuous and inescapable once the mosquito is in a fog cloud.

Regardless of their abundance, in a fog cloud are so small that they should not weigh down a mosquito enough to affect its ability to fly.

To explore this puzzle, Dickerson and his colleague David Hu used high-speed videography. They observed that mosquitoes have a reduced wing-beat frequency in heavy fog, but retain the ability to generate sufficient force to lift their bodies, even after significant dew deposition. They are unable, however, to maintain an upright position required for sustainable flight.

The reason for this is the impact that fog has on a mosquito's primary flight . Known as halteres, these small knobbed structures evolved from the and flap anti-phase with the wings and provide gyroscopic feedback through Coriolis forces (the perpendicular force generated by a rotating object).

These halteres are on a comparable size to the fog droplets and they flap approximately 400 times each second, striking thousands of drops per second. Though the halteres can normally repel water, repeated collisions with 5-micron fog particles hinders , leading to flight failure.

"Thus the halteres cannot sense their position correctly and malfunction, similarly to how windshield wipers fail to work well when the rain is very heavy or if there is snow on the windshield," said Dickerson. "This study shows us that insect flight is similar to human flight in aircraft in that flight is not possible when the insects cannot sense their surroundings." For humans, visibility hinders flight; whereas for insects it is their gyroscopic flight sensors."

Explore further: The unifying framework of symmetry reveals properties of a broad range of physical systems

More information: The talk, "Mosquito Flight Failure in Heavy Fog," is at 5 p.m. on Monday, Nov. 19, in Room 28A. http://absimage.aps.org/image/DFD12/MWS_DFD12-2012-001215.pdf

add to favorites email to friend print save as pdf

Related Stories

How mosquitoes fly in rain? Thanks to low mass

Jun 04, 2012

Even though a single raindrop can weigh 50 times more than a mosquito, the insect is still able to fly through a downpour. Georgia Tech researchers used high-speed videography to see how the mosquito's strong ...

Foggy perception slows us down

Oct 31, 2012

Fog is an atmospheric phenomenon that afflicts millions of drivers every day, impairing visibility and increasing the risk of an accident. The ways people respond to conditions of reduced visibility is a ...

3D, 360-degree fog display shown off (w/ video)

Mar 18, 2011

(PhysOrg.com) -- Any fan of Star Trek knows about the joys of the holodeck. The idea of a 3D, 360-degree immersive digital environment, projected on demand, is an enticing one that has thus far been confined ...

Researchers develop the first permanent anti-fog coating

Mar 16, 2011

Researchers under the supervision of Universite Laval professor Gaétan Laroche have developed the very first permanent anti-fog coating. Dr. Laroche and his colleagues present in the online edition of Applied Materials an ...

Recommended for you

What time is it in the universe?

Aug 29, 2014

Flavor Flav knows what time it is. At least he does for Flavor Flav. Even with all his moving and accelerating, with the planet, the solar system, getting on planes, taking elevators, and perhaps even some ...

Watching the structure of glass under pressure

Aug 28, 2014

Glass has many applications that call for different properties, such as resistance to thermal shock or to chemically harsh environments. Glassmakers commonly use additives such as boron oxide to tweak these ...

Inter-dependent networks stress test

Aug 28, 2014

Energy production systems are good examples of complex systems. Their infrastructure equipment requires ancillary sub-systems structured like a network—including water for cooling, transport to supply fuel, and ICT systems ...

Explainer: How does our sun shine?

Aug 28, 2014

What makes our sun shine has been a mystery for most of human history. Given our sun is a star and stars are suns, explaining the source of the sun's energy would help us understand why stars shine. ...

User comments : 0