Mountain Mama: How do fireflies light up and why?

Dear Mountain Mama,

The flickering of hundreds of fireflies lighting up the woods is my favorite part of the summer. It reminds me of cupping them in my hand and peaking through my fingers to see the neon light up close.

How do fireflies light up and why? 




Dear Glowbug,

There’s nothing better than a lazy summer night inhaling the perfume of blooming honeysuckle and the magical sight of fireflies light up the forest. Turns out that science, not magic, is responsible for their glow.

Bioluminescence is at play – when chemical light is produced by a reaction within a living organism. Luckily for the survival of fireflies, the chemical reaction doesn’t produce heat or else they’d incinerate themselves every time they glowed. Think how hot a lightbulb can be when you touch it. If fireflies produced that type of heat, they’d burn to death. To be more specific about how the process works, fireflies have luciferin in their abdomen. When that combines with oxygen and with an enzyme called luciferase which causes their abdomen to light up.

So why do fireflies glow? Fireflies use light signals to communicate. Summer nights in an open field are like a single’s bar where everyone wears glow sticks. Males looking to mate flash a species-specific pattern. Interested females respond with the same pattern, helping males find the way to their perch, often low on vegetation.

One sneaky species lights up to lure unsuspecting males of different species onto their dinner plate. These fireflies mimic the flashes of other species and when males, thinking they’re going to mate get close enough, they get eaten instead.

Fireflies glow well before they are ready to mate. Fireflies during all stages of life are capable of producing light, beginning with the egg, larvae and pupae. Some firefly eggs emit a faint glow when disturbed leading scientists to believe that fireflies produce light to warn predators away.

This summer when you watch the flashing fireflies, know that you’re witnessing a complex mating ritual. But don’t let the science behind their glow take away the magic of all that twinkling light. Let yourself feel the hundreds of flickering lights as your own, lighting up the possibility of summer.

Enjoy the glow!

Mountain Mama





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