[MUSIC] [BIRD CHIRP] Male crickets love to sing. But on the Hawaiian island of Kauai, that singing comes with a price. Several years ago, a parasitic fly arrived
on the island. Those flies listen for crickets’ chirping wings, lay eggs inside them, and
the crickets are devoured from within. Thanks to these flies, Kauai’s crickets
almost disappeared, except for a few. These survivors were missing the ridges that
crickets normally rub together to chirp, and today Kauai is filled with quiet crickets. Silence saved their lives.
This wasn’t just a change in behavior. The silent wing shape was caused by a mutation
on the cricket’s X chromosome. Kauai’s crickets became the strong silent
type in fewer than 20 generations. Not only did we see natural selection in action, it
happened in the blink of an eye. A few years later, those parasitic flies showed
up on neighboring Oahu, and in response, most of the crickets there had gone silent too.
Surprisingly, they had developed a completely different mutation in the same gene.
Nature arrived at the same destination by two completely different paths. While evolution is often a long gradual process,
rest assured we’ve witnessed plenty of fine tune-ing right before our eyes. Stay Curious.