Male Fireflies Use Wingmen
Fireflies, with their glowing abdomens, are a well-known summertime site in many parts of the world. Part of the beetle family of insects, certain species of fireflies can create light with chemicals inside their abdomens. This process is called chemiluminescence, and it is made possible by luciferase, a protein made by the firefly.
Male fireflies use their chemiluminescence in mating displays. Every species of firefly has its own pattern of flashes that they use to attract mates. These flashes are recognized by females of the same species. With 2000 species of fireflies worldwide, they have to be careful that they don’t waste energy trying to mate with one of another kind. Male fireflies also tend to flash in unison, although whether or not these group displays are important is unknown. In the July 9, 2010 issue of the journal Science, Andrew Moiseff and Jonathan Copeland have published new research showing that female fireflies from the species Photinus carolinus respond more often to synchronous or near synchronous displays than to randomly timed displays. So when male fireflies flash together, they attract more mates.
How did Moiseff and Copeland do their research? They used LED displays as a substitute for male fireflies, and put females in front of them to see how they would respond to different kinds of displays. When a group of LEDs flashed together in a mating pattern, similar to a group of males flashing at the same time, the females responded 82% of the time. Same with nearly synchronized flashing. But when the LEDs flashed the same pattern at random times, the females only responded 3-10% of the time. Unified displays of the mating pattern were much more successful in getting females to respond than random displays.
Why this would be is still untested. Moiseff and Copeland offer an idea. Male fireflies are small and often move while flashing. If a female loses track of the male, it can be difficult for her to tell if he is flashing the right pattern. If a group of males flash together, it could help females be sure that the males are her species. If you were working on this project, how would you test this idea?
This work was a collaboration between groups at the University of Connecticut and Georgia Southern University. It was published in the July 9, 2010 issue of the journal Science. You can view the abstract for free, or pay a small fee for the whole paper. Thanks to the Discover magazine blog 80 beats for their story on this article, which lead me to the original paper. Because I don’t always get to reading those This Week in Science/Science Site Track emails.