It took several years for the crickets of Kauai to fall silent. When Marlene Zuk first visited the Hawaiian island in 1991, she heard the insects chirping away, loudly and repeatedly. But every time she went back, the chirping diminished. In 2001, she only heard a single male, apparently singing into the void.
The crickets had disappeared from sight, too. But when Zuk returned to Kauai in 2003, she started seeing them again, seemingly in greater numbers than before. They were there, sitting on blades of grass, illuminated by her headlamp. They just weren’t singing.
To be a quiet cricket is to defy the essence of cricketkind. Crickets sing. Crickets are noisy. The males attract females by calling with a pair of specialized structures on their wings. One, the file, is a vein with several evenly spaced teeth. The other, the scraper, is a raised ridge. When the file rubs against the scraper, it’s like running the teeth of a comb along the edge of a table: It makes a thrrrrrrp sound. But on Kauai, 95 percent of the males had tiny files that grew at strange angles. When these crickets rubbed their flat wings together: crickets.
These changes happened because of a parasitic fly with sensitive hearing and a fondness for crickets. It finds males by eavesdropping on their calls and splatters their bodies and surroundings with larvae. These larvae then burrow into the crickets and devour them from the inside out. At its height, this fly had infested a third of the male crickets on Kauai, and seriously reduced their numbers. That’s why Zuk had such trouble finding and hearing them.