You see that bubble attached to the beetle? That's basically an air tank that the beetle uses so that it can breathe underwater. Because they're so small, they can use water's surface tension to trap air in bubbles on their body so they can swim under water without having to constantly come up for air. Other beetles can trap air even cooler, like a force field around their entire body that acts as a space suit of sorts.
Bugs and beetles can't hold their breath underwater like we do. But some aquatic insects can spend their whole adult lives underwater. How do they do it? Meet nature's Scuba divers. They carry their air with them — in some cases, for a lifetime.