Flashing Fireflies

Synchronous displays of male fireflies found in southeast Asia (as well as parts of America and Africa) have proved an awe inspiring phenomenon to observe for hundreds of years. Great masses of fireflies stretching out for miles all flashing light in perfect unison.

Until recently no one was able to explain how such vast numbers of these tiny insects were able to coordinate their displays in perfect synchrony without a conductor of any sort. In fact some prominent scientists of the early 1900’s insisted such a thing was ‘contrary to all laws of nature’, numerous articles were published in academic journals dismissing the phenomenon as nothing more than coincidence or illusion.

Until around 50 years ago when the pieces were put together by biologist John Buck who through observations and experiments showed that these fireflies not only flash in unison with each other but they do so to a constant tempo (of about 1 flash per second). Each insect is flashing to a beat using some form of internal clock and does so even when isolated. But when they congregate in groups these disparate underlining rhythms get pulled in to tune with those of its neighbours, each insects internal metronome is reset, rewound or advanced depending on where in its cycle it is when it observes another’s flash.

As this computer simulation shows, in the beginning each individual flashes along happily at its own pace, but as individuals perceive g the flashes of others , its own cycle is reset in time with it, either advanced or delayed, as time goes on, with vast numbers of rhythms all tugging on and being tugged by each other, slowly, pockets of synchrony start to emerge, order from chaos, until eventually almost all individuals are lighting up in perfect time.

Its believed that they do this as a selective adaption to aid mating (makes males more visible to females, makes small groups appear larger and makes the females easier to spot in-between the flashes by reducing noise)