HOW INSECTS FLY.
Aeroplanes, like most birds, derive their ability to fly largely from the specialised shape of their wings: a rounded leading edge, flattened underneath and bulging top, tapering away to a slender trailing edge. The wings of insects, however, do not have this typical aerofoil shape. Instead they are roughly the same thickness throughout.
As a result, insect wingsare used in the air in much the same way that oars are used in water. They push downwards to help the insect climb, backwards to move it forwards, and scull horizontally when the insect hovers.
Many insects also use what scientists call a 'clap-fling' mechanism - in which the wings are clapped together at the end of each beat, then flung apart at high speed - to hurl turbulent rings of high-pressure air below and behind them. The action helps to thrust the insect up anf forwards.
Some insects, like the larger butterflies and moths, are capable of gliding, twisting their wings slightly to ride the air currents. Most insects, however, and particularly the smaller ones, rely on the sheer speed of their wingbeats to keep them up.
HOW FAST THEY FLY.
Larger insects, such as dragonflies, have relatively slow wingbeats but are fast fliers. Tiny insects such as mosquitoes, beat their wings extremely fast, but fly fairly slowly. The buzzing sound made by insects is caused by their wing movements and by air turbulence. The faster the wings vibrate, the higher the pitch of the buzz. The table below shows how many complete up-and-down wingbeats each insect carries out each second in flight, and shows how fast it usually flies.
Insect Wingbeats/second Flight Speed (km/hr)
White butterfly 8 - 12 7 - 14
Damselfly 16 3 - 7
Dragonfly 25 - 40 25 - 55
Cockchafer Beetle 50 11
Hawk Moth 50 - 90 18 - 50
Hoverfly 120 11 - 14
Bumblebee 130 11
Housefly 200 7
Honeybee 225 7 - 11
Mosquito 600 1 - 2
Midge 1000 1 - 2

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