| With all the special camera equipment you see here in this film laboratory, we're going onto the water. Quite literally: not over the water, nor under the water, we're going to be on the surface of the water. Extraordinary, fascinating things go on there-- in this world in between air and water.
To us, it's just a shining, reflecting surface where the air ends and the water begins.
To others, it's the world they live in: a boundary zone flooded with light, which is why they are countless green algae floating around here.These are snail's eggs.
The little snail's black eyes can already be seen peering out.
And when they eventually emerge and become adult snails, they swim to the surface of the water and graze there on the carpet of algae.
They use their tongues to suck in the green food.
Creatures living on the surface of the water can tell a lot from ripples. We're constructed a kind of ripple cinema here -- a shallow basin of water which is lit so that the ripples slow up particularly well on the screen.
Our cinema screen we see something approaching from below.
And here it's a attacking real prey -- an ant.
But now there are more ripples -- a rival is approaching.
The fight really does make waves.
Back in the pond. Ripples reveal all kinds of information. They're even used for passing messages to on another.
"Beat it, get lost! "is the meaning of one particular ripple signal.
The indentations in the surface film are getting deeper -- but things are about to change anyway, because it's starting to rain.
The ripples produced by the raindrops as they hit the water drawn our any other signal.
Those living under water aren't affected the raindrops bounce off the surface film.
Astonishingly, this surface film not only supports the weight of creatures like the water measurer walking on top of it-- other creatures crawl along the under side of it, upside down, like this.
And that's exactly what the backswimmer does.
It grasps its victim in its forelegs and pierce it with its rostrum.
Its victim is a creature we all know and no one likes. It also hangs suspended from the underside of the surface film by its tail, which acts as a breathing tube.
It's a strange--looking creature we see emerging from the pupa and rising above the water's surface.
Now you can perhaps guess what it is.
A mosquito, a gnat.
And our bacswimmer is after mosquito larvae.
Backswimmer hunts larva.
Now he's caught it. He hangs suspended from the surface film -- what you see above is just his reflection -- and suck out its juices.
At any rate one mosquito less. Backswimmers are our allies.
The next larva -- but this time he misses.
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