Firefly vs. Lightning Bug: Is There a Difference Between the Two? Turns out the two terms are the result of regional differences. NobythaiGetty Images When you see a flashing insect in your backyard, do you call it a firefly or a lightning bug? And have you ever wondered if those names refer to two different insects? Despite their unique names, lightning bugs and fireflies are actually the exact same thing: a family of flying beetles that communicate through bioluminescent flashes. However, there is a reason for the differing terms—and it all comes down to where you live. Are fireflies different from lightning bugs?