Flashing Fireflies
Credit: Cathy Keifer | Dreamstime

Fireflies, which use bioluminescence for sexual selection, synchronize the flashing of their neon-green lights as large groups in order to help female fireflies recognize potential mates, according to a 2010 study conducted by researchers at the University of Connecticut. There are more than 2,000 species of fireflies, or lightning bugs, and they are actually winged beetles, not flies.