Fireflies, which were in short supply last year, seem to be making a resurgence this year. But did you know the reason why these fireflies light up, especially in the summertime? Here’s a primer on what fireflies are and how these lightning bugs light up summer nights. What are fireflies? Fireflies, otherwise known as lightning bugs, are known for their ability to glow at night. According to the Xerces Society for Invertebrate Conservation, fireflies are actually not flies, but are instead a form of beetle, going through the same life cycle: egg, larva, pupa, and adult. Fireflies fall into thr…