Synchronizing Fireflies

California has many natural wonders—the Sierras, Pacific Ocean, Redwoods. The list could go on and on. But the one thing we’re missing? Fireflies. This native Californian didn’t see one until the age of eighteen! They always seemed magical, but when I heard there was such a thing as synchronous fireflies, these little beetles rose even higher in my estimation. (A video of their synchronized flashes can be found here.)

Of the roughly 2,000 species of fireflies around the world, it is estimated that only about one percent synchronize their flashes over large areas. Now scientists have found a possible reason that those fireflies flash in sync—the males are teaming-up to get noticed by the females. Their research is published in the July 9^th edition of the journal Science.

All female fireflies look for the species-specific pattern of flashing to find their mates, so that’s where the researchers started. They collected females of the synchronous species Photinus carolinus from the Smoky Mountains National Park in Tennessee. In the laboratory, they exposed the females to groups of light-emitting diodes (LEDs), meant to mimic male fireflies. Each individual LED produced the species-specific pattern of flashes for P. carolinus, but the experimenters varied the degree to which the flashes were in synch with one another.

Their results showed that females responded more than 80 percent of the time to flashes that were in perfect unison or in near-perfect unison. But when the flashes were out of synch, the females’ response rate was 10 percent or less.

Synchronous species are often observed in high densities and the male fireflies are typically in flight while searching for females, so their flashes appear in different locations over time. Therefore females must be able to recognize visual cues over a wide range of space, according to lead author Andrew Moiseff, PhD, of the University of Connecticut.

He goes on to say in New Scientist that:

If the male fireflies all flashed in the dark in their own time, it would be difficult to distinguish the patterns. In that situation, you can't pick out the rhythm from any single [species]. It’s just noise.

Scientific American points out that this research might tell us more about how our own brains are wired.

“Animals have evolved to solve unique problems in many different ways, and I'm interested in how they do that,” Moiseff says. “Fireflies have these tiny heads and these tiny brains, but they can do some complex and amazing things.”

Creative Commons image by Quit007