Sara Lewis is fluent in firefly

The fireflies flashing in the air are all males. Down in the grass, Dr. Lewis points out, females are sitting and observing. They look for flash patterns of males of their own species, and sometimes they respond with a single flash of their own, always at a precise interval after the male’s.

Dr. Lewis takes out a penlight and clicks it twice, in perfect Photinus greeni. A female Photinus greeni flashes back.

“Most people don’t realize there’s this call and response going on,” Dr. Lewis said. “But it’s very, very easy to talk to fireflies.”

For Dr. Lewis, this meadow is the stage for an invertebrate melodrama, full of passion and yearning, of courtship duets and competitions for affection, of cruel deception and gruesome death.

In recent years scientists have analyzed the DNA of fireflies to figure out how their light has evolved

Dr. Lewis wondered if the female fireflies were picking their mates based on variations in the flashes of the males.