As adults, the earliest fireflies probably communicated with chemical signals, the way some firefly species do today.
The more Dr. Lewis watched firefly courtship, the clearer it became that the females were carefully choosing mates. They start dialogues with up to 10 males in a single evening and can keep several conversations going at once. But a female mates with only one male, typically the one she has responded to the most.
The female fireflies turned out to be remarkably picky. In many cases, a male flash got no response at all. In some species, females preferred faster pulse rates. In others, the females preferred males that made long-lasting pulses.
http://www.nytimes.com/2009/06/30/sc...nted=2&_r=1&hp
saw some parallels here