The Secret of Fireflies’ Synchronous Flashing
Some of the mathematical mysteries behind how groups of male fireflies match their flashes when grouped closely together have recently been illuminated by a group of scientists at the University of Colorado Boulder who study firefly blinking.
Now, in a follow-up study, researchers report additional experiments that shed even brighter light on fireflies’ synchronous blinking. Of the approximately 130 species of fireflies found in the United States, only three exhibit such synchrony. One of them, phototuris frontalisis concentrated in protected natural areas in the eastern United States, such as Congaree National Park in South Carolina, where the study authors witnessed the phenomenon.
“It’s magical,” marvels computer scientist Orit Peleg in a press release. “At certain times of the night, the fireflies have a unique rhythm for the whole group, and they are very punctual.”
The research team of computer scientists like Peleg and mechanical engineers captured male fireflies in the same old-growth forests where they had conducted their previous studies, which demonstrated that only males synchronized their blinks. Next, the captive males were placed in a completely dark tent and exposed to a small LED light flashing at regular intervals.
Read more: “The mathematical mysteries of fireflies”
In the wild, these males flash once or twice per second. In the experimental setup, LED blink rates varied from once per second to once every 300 milliseconds (about a third of a second).
The male fireflies followed the rhythm of the lights, provided that the first flash of the LED was close to their own flash. If the LED light flashed just before the firefly flashed, the males rushed to catch up, apparently anticipating that the next LED flash would arrive sooner. If, conversely, the LED light flashed immediately after the firefly flashed, the males would wait longer to flash again.
Of course, male fireflies in the wild would see several flashes from other males; Yet their ability to keep pace with the LED highlights a mechanism underlying their ability to synchronize across entire aggregations of fireflies.
From the data, the study authors developed what mathematicians call a “phase response curve” for firefly flashes — essentially, a formula that describes how an outside light source causes fireflies to change their own flashing patterns. “This research opens the door to discovering other examples of synchronization in nature that we haven’t seen yet,” explained lead author and computer scientist Owen Martin.
Yet another mystery remains to be unraveled: why males of certain firefly species synchronize their flashes in the first place. No matter how many flashing lights cause this question, the answer remains elusive.
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Main image: arthurgphotography / Shutterstock
