Yes insects can work on or perch on water without sinking, because of surface tension on the surface of water.
Though the surface tension plays the major role. But the light in weight of insects should also not be discarded.
Not only insects can float on water due surface tension, razor blade, when gently place on the surface of water can also float on water do surface tension.
What is surface tension ?
Surface tension can be defined, as the a parallel forces existing on the surface of water.
This force makes the surface of water look as if it is covered by elastic skin
So the reason why insects can float on the surface of water naturally without sinking is because of surface tension period.
For surface tension of water to remain intact the water must not be violently disturbed, if not water will lose the surface tension at the time when the surface of water is disturbed.
And regain the surface to tension when the surface of the water become calm.
Now you have known why insects can walk on water without sinking.
So next time you see insects walking on a surface of water you will not be surprised.
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