HOW ARE WATER BEETLES ABLE TO STAY UNDERWATER FOR LONG PERIODS OF TIME?

Some water beetles such as the whirligig beetle go under water with an air bubble that serves as a lung: oxygen from water dissolves into the balloon, and carbon dioxide from the beetle dissolves into the water via the bubble. Using this simple mechanism, beetles can stay underwater for long. The whirligig beetle, for example, can fly or crawl on water, in addition to submerging.

Its compound eyes can see below and above pond water but they lose effectiveness when they come into contact with water. Its eyes are kept oiled to repel water.