Did you know that, before they romantically illuminate the night, fireflies start out as fierce hunters that track down otherwise protected animals and kill them with venom? Learn about the cutthroat life of firefly larvae.


I know it’s naive to assume that just because an animal is pretty, it’s actually benign—but somehow, I thought that firefly larvae were small, translucent aquatic creatures that survived on algae and the work of John Keats. And when they become adults, most fireflies eat pollen, but a few just stop eating and accept their ephemeral natures.

But now I know that they stalk the Earth like armored centipedes, hunting, killing, and devouring creates much bigger than themselves.


They can do this because they have a numbing agent that they can inject into their prey. It immobilizes the animals—usually slugs and snails—so the larvae can rip them to pieces and happily devour them. One insect enthusiast found a firefly larva and brought it back to his lab, to observe how it ate. He watched as the larva calmly walked up to snails, forced its way into their shells through the little aperture on the front, and paralyzed and ate them from the inside out. This was always successful—and you can see for yourself, with the video above of the larva eating, surrounded by the shells of its past victims. The only animal that stood a chance against a firefly larva was a slug, and that’s because the slug secreted so much slime that it took the larva over ten minutes to eat its way out.

Fireflies are such bad news that some of them glow before they even fly. The glow is a signal to predators—sure, you can try to tangle with me, but you’ll be sorry.