Around this time of the year, flies get into your house and start buzzing around the room and batting against your windows. You chase one from room to room and with persistence, eventually flatten it against a window.
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Its parting gift is an oily smear, which gives a hint why they're so hard to swat.
Their little bodies are packed with fats and proteins, which makes them a desirable snack, if you like that sort of thing. Not for humans perhaps, but for birds, spiders and lizards, they are an important source of food.
Understandably, the flies see it differently and have evolved a set of highly effective defences.
Their small size is one asset. Your diminutive target needs only to propel - literally - its flyweight.
It weighs less than a gram while your arm plus fly-swatter is more like three kilograms.
That's a lot more weight for you to mobilise, and you can't really change the direction once you've started the swing.
Surprisingly, the fly's tiny brain is also an advantage. While you are able to perform complex calculations, that comes at the expense of firing up billions of neurons.
Compare that to the fly, which has a vastly smaller brain. Yet it is able to calculate an escape route within about 100 milliseconds of spotting an incoming swat.
Meanwhile your reactions are far slower. For example, in a traffic emergency, you need about a second to realise what's happening and take evasive action.
Using energy coiled in its legs, the fly launches itself in an instant. It then switches into controlled flight and demonstrates astounding aerodynamic abilities.
They're so fast, researchers had to use three high-speed cameras, each taking 7500 frames per second, to see what they do.
Footage showed that fruit flies could flip and change direction within one or two wing beats, a feat well beyond the best fighter jets.
A fly-swatter has a largish surface area, which pushes a strong puff of air ahead of it, giving the fly a handy push. A rolled up newspaper is similar, depending on how tightly bundled it is. (You could use today's Ask Fuzzy page once you've finished reading it.)
Generally, a gradual swat is more effective than a high-speed one. Apart from taking away the fly's wind assistance, their reactions are less attuned to the slower movement.
This would relate to how they detect movement from their extreme wide-angle compound eyes. It also negates the sensitive hairs on their bodies that are triggered by air movement.
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