How crickets lost their chirp
Chirping crickets are an instantly recognisable soundtrack to a hot day - males make the noises by rubbing their wings, in order to attract females. But some crickets living on the tropical paradise of Hawaii have lost their chirp, and researchers at the University of St Andrews think they have figured out why.
Writing in the journal Current Biology, the scientists discovered that crickets on two separate islands independently evolved changes in their wings that silenced their chirps, in response to parasitic flies that are attracted to the male song and kill them within a week. The researchers used genetic analysis to prove that the populations on the two islands had evolved the trait separately, finding that they had different genetic changes.
Sneakily, these quiet crickets still manage to get a mate by perching next to males that still make noise, but their silence opens a window on the processes of rapid evolution in the wild.