True Bugs, Pacific Northwest
Back swimmer bugs are insects of the order heteroptera that occur worldwide and are named for their ability to swim on their backs, which are shaped like the keel and sides of a boat. They uses its long, oar like legs for propulsion and has an oval shaped head and an elongated body that usually is less than 15 mm in length.
It is a good example of counter shading, as its light colored back, seen from below, blends into the water surface and sky. The rest of the body is darker and when seen from above, blends with the dark water below.
Because they are lighter than water, it will rise to the surface after releasing its hold on the bottom vegetation. Once at the surface it may either leap out of the water and fly or get a fresh supply of air, which is stored under its wings and around its body, and dive again.
The back swimmer is often seen floating on the water surface, with its legs extended, ready to dart away if disturbed. It preys on insects, small tadpoles, and fishes, sucking their body fluids through its strong beak.