Entomology: Swamp Lights

In Southeast Asian swamplands, it has long been observed that thousands of fireflies flash together, lighting up trees with the regularity of neon signs. This synchronous flashing has never been adequately explained. North American fireflies generally light individually or sometimes in uncoordinated group flashing. Writing in Nature, Zoologist John Buck and his wife believe that the Asian male fireflies’ synchronous flashing is actually a photic call that lures females to the trees for mass mating. Because the Asian undergrowth is so dense, the male insects use rhythmic beaconing in order to shine through and be seen by the females. In effect, the synchronous flashing becomes mass advertising.

But how the Asian lightning bugs maintain their coordinated flashing is “one of the great mysteries of physiology,” says Dr. Buck. Once this is fathomed, however, it may lead researchers toward a better understanding of nervous-system mechanisms that allow humans to act in perfect unison.