Evolution silences some isle cricket populations

Scientists investigating the silence of the crickets in Hawaii have uncovered a bizarre evolutionary story that is part horror movie, part Cyrano de Bergerac.

In the most recent edition of the journal Current Biology, researchers from Scotland’s University of St. Andrews report on the separate but nearly simultaneous quieting of chirping crickets on Kauai and Oahu.

As lead researcher Nathan Bailey explained, Hawaii crickets appear to have abandoned their chirplike mating songs to avoid parasitoid flies. The flies, which are attracted to male cricket song, would lay larvae that would then burrow into the host crickets, killing them within a week. 

Adaptive crickets survived and reproduced by silencing their own songs but positioning themselves — like Christian to Cyrano — next to crickets who continued to use their chirps to woo female crickets.

The silent flatwing crickets are present on both Oahu and Kauai. At first, Bailey and his team believed that a single population of silent crickets evolved on one island and spread to the other. However, further investigation made it clear that the crickets came from separate populations but adopted the same trait around the same time.

“This is an exciting opportunity to detect genomic evolution in real time in a wild system, which has usually been quite an challenge owing to the long timescales over which evolution acts,” Bailey said in a release. “With the crickets, we can act as relatively unobtrusive observers while the drama unfolds in the wild.”