We have probably all seen a water strider walk on the water. How does it do that?

Surface tension. What is it? It is the cause of dew forming in drops on a leaf, the reason why water drips from the faucet or falls as drops of rain, the reason it is possible to float a razorblade or a needle on the surface of water. Surface tension is the force of molecules on the surface of a liquid.
Surface tension is so strong that it is impossible to blow bubbles with pure water. It is strong enough to hold up the weight of a water strider or Jesus Bug, so named because it can walk on the water. Water Striders are flat and long without wings, and easy to identify by the second and third pairs of legs that are almost twice as long as their bodies. They have short forelegs to attack and hold their prey. Striders live on the surfaces of ponds, slow streams, and other quiet waters. They often gather in small groups.
Water Striders are both predators and scavengers. They feed on such things as seed shrimp, mosquito larvae, and insects that drop into the water. The Water Strider has a piercing, sucking mouth. It pushes its mouth into the insect prey and sucks it dry. It can locate its prey by feeling the smallest movements or vibrations made in the surface of the water.
Water Strider legs grow water-repellent hairs that hold tiny air bubbles, allowing them to skate on the surface of the water. Striders move with the jerking, pushing movement of their middle legs and steer with their back legs. Their bodies are covered with soft, velvety hairs that hold a thin film of air through which they breathe.
Water Striders can escape predators by running across the water and even by going underwater. When the danger is past, they pop to the surface of the water and stand back up on their four legs. But one thing they can’t deal with is a lack of surface tension.
We all know that, to blow a bubble, soap of some type must be added to water. This lowers the surface tension just enough to form the bubble. The Stenus Water Beetle, enemy of the Water Strider, also knows this. Though the Water Beetle is no match for the speed of the Strider, it doesn’t need to be. The Water Beetle has the ability to make and shoot out a soap like chemical onto the water (actually four different chemicals that are large and complex). The surface tension is thus decreased, the Water Strider sinks, and the Beetle has lunch!
How did the Water Strider learn how to walk on water? How did the Water Beetle learn to make these chemicals to sink its prey? Sounds like design to me!