The Invisible Crane Fly

Many years ago I was breaking through an eighteen inch thick brick wall from outside. In a pause in my labours I became aware of a light buzzing noise close at hand. Concentrating on the noise I became convinced that it came from a small area in front of me, but I was unable to see any cause.

However, after a few more minutes the noise stopped and a crane fly appeared in the area I was watching. Watching the crane fly I hit the wall with my hammer and the crane fly immediately ‘disappeared’ again. Close scrutiny of the area allowed me to identify the lower few millimetres of the crane fly’s legs, but the rest of it was invisible. I carried out this procedure a few more times before blowing it away from the area that I was working in.

The question is, ”Is this a commonly known phenomena, or was it just a very clever crane fly that I was watching.”

Occasionally I have looked ‘crane flies’ up in various books, and recently on the internet,  but have yet to find any mention of this ability.

Possibly this explains why when your wife gets you out of bed to kill an annoying crane fly and you miss the first attempt because you are still dopey,  the crane fly  ‘disappears’ even though you can still hear it, but you didn’t see it fly off as you would with a fly or wasp.

You can now ask  “What has this got to do with physics?

Well, biology is part of physics (or should be), and crane flies are part of biology, and here we have an insect that can adopt a ‘cloak of invisibility’  (Magic) which it creates by means of classical mechanics, and all of modern physics can be explained by classical mechanics. Unfortunately, the physicists never seem to get beyond the ‘Magic’ stage of research. They have an inbred revulsion of mechanics which prevents them from progressing further. See Introduction

Note: My particular crane fly set up an oscillation in it’s body by rapidly moving it’s wings in a non-flying sequence. This oscillation is faster than the eye/brain can handle, therefore the crane fly ‘disappears’. This is indicative that the oscillation is just as effective with all of it’s natural predators, and thus that all it’s predators have the same optical frequency limitations that humans have.

It’s common British name “Daddy long Legs”  indicates its most recognizable feature, which must be the main reason it can carry out it’s disappearing act, which would not be possible in a short legged insect.  What we will never know is whether the oscillation initially had a different purpose (which may still be required) and the long legs evolved to provide the ability to ‘disappear’.