High-speed imaging sheds
light on secrets of fight
Using high-speed imaging and computational fluid dynamics, the unique mechanisms
involved in mosquito flight have been revealed.
Dr. Simon Walker
Although a great deal is known about the behavior of mosquitoes, scientists have previously
struggled to understand fully the aerodynamic principles that enable them to fy. Recently however, a collaborative effort between scientists at Oxford University (Oxford, UK;
www.ox.ac.uk), the Royal Veterinary College
(London, UK; www.rvc.ac.uk) and Chiba University (Chiba, Japan; www.chiba-u.ac.jp/e/)
has provided an insight into the unique mechanisms involved in mosquito fight.
Well known carriers of diseases, mosquitoes’ abnormally long, narrow wings and distinctive fight behavior set them apart from
other insects. When fapped, their wings move
back and forth approximately 800 times each
second–faster than any other insect of comparable size. To compensate for these rapid
movements, the angle through which their
wings sweep (or stroke amplitude) is less than
half that of any other insect measured to date.
However, the fapping pattern of short, fast
sweeps means that mosquitoes cannot solely
rely on the lift-enhanc-ing mechanisms typically used by other insects.
Research has now dem-
onstrated that much of
the aerodynamic force
that supports their weight
is generated in a manner unlike
any previously described.
To reach this conclusion, a
high speed imaging technique
was employed to capture images
of the mosquitoes in flight.
Then, from the digitized outlines of the wing and body produced from an analysis of the
moving images, a Computational Fluid Dynamics (CFD)
model of the insect was created
to show the airfow produced by
their beating wings. The results
of the CFD analysis were then
compared to the results obtained from particle
image velocimetry (PIV) experiments to verify
To capture images of the insects, eight SA3
high-speed cameras from Photron (San Diego,
CA, USA; www.photron.com) were arranged
to view a volume of 20 x 20
x 20 mm at the center of a
fight arena measuring 330
x 330 x 230mm designed
specifcally for the project
(Figure 1). Theoretically,
only two cameras are necessary to capture the
3D coordinates of an insect any instant in time.
However, by using eight cameras, the imaging
system could capture enough views of the mos-
quitoes to allow the images to be processed to
discern wing motion.
In the experiments, the cameras were man-
ually triggered to capture images of the mos-
quitoes as they entered the recording volume.
The cameras, ftted with 180mm macro lenses
from Sigma Corporation (Kanagawa, Japan;
www.sigma-global.com) and Tamron (Saita-
ma, Japan; www.tamron.jp/en) with an aper-
ture of f/16, captured images at 10,000 fps with
an exposure time of 5μs so that the motion of
Dr. Simon Walker, Universi-
ty Research Fellow, Department
of Zoology, Oxford University,
Oxford, UK ( www.ox.ac.uk)
Figure 1: To capture images of mosquitoes in fight, eight
high-speed cameras were arranged to view a common volume at the centre of a transparent polycarbonate fight arena.