Why do grasshoppers make chirping sounds?

Grasshoppers often chirp by rubbing their hind legs against stiff edges on their wings or body. This stridulation creates species-specific calls that help males attract females and advertise to rivals. Sound production is especially common in warm weather because muscle activity and calling rates rise with temperature. The diversity of grasshopper songs is one reason they are useful in ecological studies, where scientists can identify species by sound. These sounds are a major part of insect communication in fields and grasslands around the world.