According to the researchers, the sound reflects (probably) the attraction sound i.e. love song to attract its mates.
"Singing loud and clear advertises the presence, location and quality of the singer, a message that females choose to respond to -- or not," he said.
"Using a single tone, the male's call carries further and better, and therefore is likely to serenade more females."
"This Jurassic bush cricket... helps us learn a little more about the ambiance of a world long gone," said co-author Fernando Montealegre-Zapata of the University of Bristol.