OXFORD AND HATFIELD, ENGLAND, UK (REUTERS / NATURE) – Scientists have solved the mystery of mosquito flight using super-high speed cameras and computer analysis to understand the unique mechanisms the insect uses to stay airborne.
Despite solving the bumble bee paradox some time ago, which stated the bumble bee should not be able to fly under normal rules of aerodynamics, until now science was been unable to explain how mosquitoes managed to flap their wings through such a short angle and still produce enough lift.
Published in Nature, the team describe the difficulty of filming Culex Mosquitos which flap their wings through an arc of around 40 degrees at a rate of nearly 800 beats per second, 4 times faster than many insects of a similar size, making filming them very difficult.
A collaboration between Oxford University’s Animal Flight Group, the Royal Veterinary College and Chiba University in Japan managed to overcome the technical challenge of capturing video of such a small creature with large antennae and legs masking the view of its wings flapping at such a speed.
“We got round it by using state-of-the-art infra-red LEDs and designing a custom lighting rig and also by using eight camera views. So normally to record an insect you need at least two cameras, ideally more, so you’ve got enough views of an insect because with two camera views you can then take any point on an insect and calculate its 3D co-ordinates. But because of the problems with the antennae and the legs we ended up needing to use eight cameras just to ensure that at any point in time we had enough camera views of the mosquito where we can actually see its wings clearly,” said Dr Simon Walker at the University of Oxford’s Department of Zoology.
The technology, shooting at 10,000 frames per second, revealed techniques not seen before in insect flight.
“Mosquitos use three aerodynamic tricks in order to support their body weight. The first of these is a leading edge vortex which is actually used by pretty much all insects but mosquitos actually have a much lower reliance on it than other species. The second two are a trailing edge vortex and rotational drag and these last two are novel to mosquitos and they both rely on the really subtle, precise rotations of the wing at the end of each wing beat,” Walker said.
The trailing-edge vortex is a new form of ‘wake capture’, where the mosquitoes align their wings with the fluid flows they created during the previous wingbeat, recycling energy that would otherwise be lost.
The team believes the technique could inspire innovative designs for micro-scale flying devices in future.
“We have smallish drones but we have nothing down to the size of an insect and certainly not down to the size of a mosquito where the whole body is only a few millimetres long. And any of these small drones you can buy, which are normally quadcopters, they work really well when you fly them inside but as soon as you take them outside and there’s the hint of a breeze or any gusts they tend to fall out of the sky or at least be very, very hard to control. Insects on the other hand deal really, really well with even quite windy conditions. So understanding how they can do this is going to be advantageous to us in the future,” said Walker.
Walker hopes a better understanding of mosquitoes’ flight will helps us understand how they carry disease and eventually how to stop them from doing so.