Flashing Fireflies
I have many childhood New England summer memories of lying down on the cold grass at night, looking up at the stars, and being completely surprised and excited when I see a flash of dancing light right above me. Tiny little fireflies--they cary so much wonder and magic seen through children's eyes, and can be a wonder for adults, too.
Some species of firefly native to Southeast Asia congregate and begin to flash simultaneously. Imagine a whole group of insects packed together, pulsing seemingly as one organism. This is interesting behavior because (quite like ant colonies) there is no leader organizing their behavior. Simply bring a group of fireflies of the same species together, and they will begin to synchronize their luminescence. It takes about half an hour for this coordination of a whole flock of fireflies to occur, as each individual begins at it's own frequency, changing after every pulse to become more coordinated with other individuals around it. Over time, you can see small groups of coordination begin to form, which merge with other groups, which merge with larger groups, until the entire group pulses at the same rate, synchronized.
Mathematicians have come up with a model for how this synchronization occurs. The Strogatz-Mirollo model shows that a system of oscillators (firefly flashes) started at random times will eventually reach synchrony, assuming that the oscillators behave identically, and are coupled to or influenced by others.
However, we have not yet been able to discover why fireflies from some species coordinate flashing. In general, flashing is used as a warning to predators for their impalpability, as fireflies produce distasteful defensive steroids. Flashing is also used for mating rituals, as females distinguish different species and viable males by the flash pattern and intensity of the flash. So far, no theory as to the benefits of a group of flashing fireflies has been tested.
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Posted by Rachael Mroz (6)
It would be fascinating to study what time of year and conditions must be present for fireflies to exhibit this behavior. If they flash as a way of sexual selection, maybe this behavior is apparent during the mating season of these insects. Also maybe there could be a fierce predator that startles the fireflies and gets them to congregate in such a manner to help ward of the predator.There could possibly be some kind of benefit to the fireflies from joining in such a large group.
ReplyDeleteThese would be all great inferences to look into and I wonder if any scientists are doing any studies or have hypotheses about this kind of group behavior in this species of insect.
Posted by Noelle Kellicker
Perhaps there is an evolutionary advantage to flashing at the same time. For example, they might deceive predators into thinking that instead of being hundreds of small fireflies, it is one giant organism. Or another advantage would be the light attracts other fireflies into the flock, which would increase the firefly's chances of mating. I wonder what the mechanism behind the coordination is. I imagine it would be pretty hard to get synchronized if one firefly tried to match up with another and then at the next cycle change its flash to match up with a different one.
ReplyDeletePosted by James Lin