Kauai's crickets were in trouble. They were being victimized by a parasitic fly that targeted them by listening for their chirps. Once the fly found them, its larvae burrowed inside the crickets and ate them alive. In the 1990s, nearly a third of the male cricket population on the Hawaiian island had been victimized. But by 2003, the population had rebounded. Why? A small number of male crickets developed a mutation on the backs of their wings that made them silent. It hobbled their ability to mate but probably saved their lives. It was a classic example of rapid evolution.
-- The Washington Post