In 2003, a number of male field crickets on the Hawaiian island of Kauai were born without the ability to chirp. Two years later, the same thing happened on Oahu.

Researchers thought the events were related — a genetic mutation that spread from one island to the other through commercial transport, or perhaps even a flying cricket that found its own way over.

But now, researchers report that the mutant males on each island stopped singing independently, through two similar but distinct adaptations.

“It’s an example of convergent evolution,” said Nathan Bailey, a biologist at the University of St. Andrews in Scotland and an author of the new study, which appears in Current Biology. “And it’s exciting because we are catching this mutation as it’s happening in the wild.”