Lightning Bugs Vs. Fireflies, Loopy 5s, & Other Facts On Glowing Beetles

University of Georgia entomology graduate students witnessed countless members of the Photuris frontalis — or snappy sync — firefly species blinking in unison in north Georgia earlier this month. (Photo by Horace Zhang)


While July 4th fireworks already seem a distant memory, the summer sky will still be lit thanks to fireflies, or lightning bugs. Here’s some fun facts:

  • Whether you call them lighting bugs or fireflies depends on your location. “Firefly” is the more common term in the West and New England, while people in the South and most of the Midwest tend to say “lightning bug.”
  • One possible theory for the two names? As meteorological researcher Jason Keeler noted on Twitter, the areas where people say “lightning bug” overlap with where lightning strikes are particularly frequent. Meanwhile, “firefly” is more common in most of the West, which experiences the most wildfires.
  • There are about 2,000 species of fireflies, according to National Geographic. In North America, there are over 150 species, according to Mass Audubon.

The following facts are all from the University of Georgia College of Agricultural & Environmental Sciences Newswire:

  • Fireflies are not actually flies or bugs, but nocturnal beetles. They are in the insect family Lampyridae.
  • The glowing light produced by adult fireflies, called bioluminescence, comes from light-producing lantern organs in their abdomen where the chemicals luciferase and luciferin work with other substances in the insect’s body to produce light without generating heat.
  • The flash patterns of fireflies are unique to each species and allow these insects to locate potential mates. In general, the males flash as they fly, while the females flash as they wait in tall grass or on other plants.
  • Snappy sync is one of the few species of synchronous fireflies. These exceptional fireflies start low to the ground with a couple of off-beat flashes, followed by a dark pause, and then all the beetles of the species flash together in unison. Other species names include bush babies, big dippers, candle lantern, fast 5s.
  • The rare Photuris forresti, better known as the loopy 5s, has a photogenic flash train.
  • Females generally deposit eggs on the ground under mulch, around log bark, or in other moist forest debris. In approximately three weeks, the eggs hatch into insect larvae that are often luminescent — they glow. The crawling, soft-bodied larvae feed on slugs, grubs, or earthworms before transitioning into a pupal stage, when they are in a case-like structure similar to a cocoon. The adult insects emerge in mid-summer to begin the lifecycle again. They are in adult form for about two months, though the entire lifecycle can take one year.
A group of University of Georgia entomology graduate students witnessed thousands of fireflies of different species, some rare, in a 100-acre wood owned by a local citizen entomologist. (Photo by Horace Zhang)


Here is how to provide habitat for fireflies in your landscape:

Photo by David Cappaert, Michigan State University,
  • Add flowering plants of varying heights. Include tall grasses as well as trees and shrubs in your landscape.
  • Turn off outdoor night lighting during mid-summer. Light pollution is thought to disrupt firefly mating and could be a major cause of firefly population decline.
  • Leave parts of your landscape undisturbed with leaf litter and plant debris as safe places for the insects to deposit eggs and for overwintering.
  • Provide a clean water source on your property. This could be as simple as a birdbath lined with rocks or a plant pot bottom with filled pebbles and water. The insects need access to water without the possibility of drowning.
  • Limit pesticides on your property.