What makes firefly glow

When a female recognizes the flash from a male of the same species, she will answer with her best flash. Another reason that fireflies glow is to avoid predators. Fireflies are filled with a nasty-tasting chemical called lucibufagens, and after a predator gets a mouthful, it quickly learns to associate the firefly's glow with this bad taste!

So not only does the flashing help attract a mate, it also warns predators to stay away. One species of firefly that can't make its own lucibufagens acquires it by eating others that can.

To lure victims, these fireflies mimic the flashing pattern of another species. When the unsuspecting male approaches to find a mate, he instead becomes a tasty treat to the tricky firefly. Interestingly, not all fireflies produce light; there are several species that are day-flying and apparently rely on the odors of pheromones to find each other.

Each firefly species has its own signaling system. In most North American species, the males fly around at the right height, in the right habitat and at the right time of night for their species, and flash a signal unique to their kind. The females are sitting on the ground or in vegetation, watching for males.

Then the two reciprocally signal as the male flies down to her. If everything goes right, they mate. A good example is Photinus pyralis , a common backyard species often called the Big Dipper. A male flies at dusk about 3 feet off the ground.

If she sees a fellow she likes, she waits two seconds before making a half second flash of her own at the third second. Firefly light communication can get much more complicated; some species have multiple signaling systems, and some might use their light organs for other purposes.

While most male fireflies do their own thing and flash independently of other males of the same species, there are those that synchronize their flashes when there are many others around. In both these species, scientists think the males synchronize so everyone has a chance to look for females, and for females to signal males. These displays are spectacular, and the crush of folks wanting to see them at the most famous locations has made it necessary to conduct a lottery for permission to view them.

Both species, however, occur over wide geographic ranges, and it might be possible to see them in other, less congested places. Many fireflies protect themselves from predators with chemicals called lucibufagins. These are molecules the insects synthesize from other chemicals they eat in their diet. Lucibufagins are chemically very similar to the toxins toads exude on their skins, and while they are toxic in the right doses, they are also extremely distasteful.

Birds and other predators quickly learn to avoid fireflies. This photo was submitted to Your Shot, our photo community on Instagram. Follow us on Instagram at natgeoyourshot or visit us at natgeo. Share Tweet Email. Why it's so hard to treat pain in infants.

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