Water striders are the spider-like insects which can walk on the surface of water. Its long legs bend like spring steel in response to the surface tension of the water molecules whereas a short, rigid leg would sink. There is a measurable relationship between leg length and weight-bearing. Short, rigid legs would sink, but increased length means more weight can be supported. However, there is a point at which more weight will not be supported no matter the length. Guess how long water striders’ legs are—just short of this critical measurement, maximizing the weight support. Answers in Genesis asks, “The question is, how many generations of water striders would have to drown before developing the ‘just right’ combination of leg rigidity and length, body weight, etc.? Natural selection could not have favored intermediate forms that all drowned on the way to the only water strider that didn’t drown!” Because they would have drowned before reproducing and passing on the ‘partial mutation’ in their genes. Their legs are the perfect length because God designed them that way from the beginning. Otherwise they could not have survived. You can believe what God said He did in Genesis chapter one.
Zelkowitz, Rachel. “Water Striders Put Best Foot Forward” ScienceNow 8/8/08