The first time I remember seeing fireflies at night was a few years ago, at a bonfire at my friend’s house in Ontario. I honestly don’t think I’d seen them before then, so I was simply mesmerized by the beautiful glowing lights that would flicker on and off. Since then I’ve always been fascinated by these insects, so I’m glad I finally have a chance to blog about them.

Fireflies are actually a type of beetle, something that was quite the surprise to me. There are around 2000 species of firefly that make up the family Lampyridae. They are found over a broad range of temperate and tropical environments, being particularly prominent in marshes or wet woodlands.

With 2000 species, it would be difficult to describe the characteristics of each individual species, but there are certain traits that most species share. They are usually brown in colour, with soft bodies and leathery wings. Depending on the species, females and males can look very similar, or the female fireflies can resemble the larvae of the species.

Pretty much your basic adult firefly.
Image by Terry Priest, CC BY-SA 4.0, via Wikimedia Commons

Of course, the most famous trait of fireflies is their ability to emit a glowing light. A special enzyme called luciferase causes this glow, acting on the chemical luciferin while in the presence of certain other chemicals to produce light. This light production is pretty amazing, as it’s able to emit a glow without expelling much heat – which is much more energy efficient than human lights.

Both larvae and adult fireflies can emit light, depending on the species in question. The function of the light appears to be different in larvae than in adults, as larvae use the glow to warn away predators (fireflies taste really bad), while adults mainly use their light to attract mates. When trying to find a mate, fireflies will use a number of techniques, including flashing their lights in different patterns. Some species congregate and show remarkable synchronization of their flashes, with large groups of fireflies blinking their lights at the same time. Other species have learned to use flash patterns to their advantage, with females mimicking the flash pattern of a different species to lure an unsuspecting male to his death.

Fireflies are truly amazing. This scene looks like something out of a fairy tale.
Image by Mike Lewinski from Tres Piedras, NM, United States, CC BY 2.0, via Wikimedia Commons

After two fireflies do manage to meet and get along, the female lays eggs below the ground, where they stay until hatching a few weeks later. The larvae are predatory and feed themselves over the summer on snails, slugs and other insect larvae. When winter comes, the larvae hibernate, either hiding underground on under the bark of trees. Some species of fireflies can hibernate for a year or more. Come springtime, the larvae fill their hungry bellies and then pupate, emerging as adults two weeks later. Adults eat a number of different foods depending on the species, with some being predatory, other eating pollen or nectar, and still others having no mouths at all.

Though they are famous for their bioluminescence, not all fireflies actually produce light. There are some species that are active during the day time, where having a glowing light wouldn’t be very useful. I feel bad for those species – after all, what’s the point of being a firefly if you can’t even produce light?

Cover image by Bruce Marlin, CC BY-SA 2.5, via Wikimedia Commons