The A to Z Challenge – B for Bioluminescence |

I’m participating in the A to Z Challenge. It began yesterday on April 1st and will run for 26 days. Each day, excluding Sunday (which I’ll be using for the Sneak Peek), I’ll write a post for each letter of the alphabet. Follow this link to nearly 2000 other bloggers and authors. The A to Z Challenge – participating blogs

Today’s Calliope’s Writing Tablet post is brought to you by the letter B — B for Bioluminescence.

Who hasn’t captured a firefly on a warm summer evening? I remember those bug-smelly jars with holes punched in the lids and a handful of grass on the bottom. In my Chicago neighborhood, mobs of children scrambled over lawns at dusk with one thought in mind – to catch the most.

Those summertime flashes are known as bioluminescence – a natural ability of some living organism to emit cold light. In our human experience, light almost always gives off heat: sunlight, firelight, gaslight, electric light, nuclear reaction light. In the animal kingdom, this heat-free process is seen in sea creatures, certain insects and their larvae, worms, and spiders. We also see it in mushrooms and bacteria. From the first time my grubby little hands held a stinky firefly I’ve wondered how it lit up its tail end. Now I know. 🙂

The cold light is produced by chemical reaction. One chemical, luciferin** is a substrate – a substance which is acted upon by an enzyme. The other chemical is the enzyme itself – luciferase. Different creatures produce a range of these chemicals, resulting in different colors of light.

Fungi glow bluish-green night and day. This too is a chemical reaction, but the verdict is out on just what the purpose is. Some scientists feel it deters creatures that would eat the fungi, while others feel it’s a way to draw attention and get better spore distribution. And others believe, in some species, this glow attracts beneficial insects that eat damage-causing insects. Bioluminescent bacteria are believed to use their glow to communicate with one another. While fireflies are somewhat yellow, marine life most often produces the color blue. This makes sense because the color blue falls in the high-frequency end of the visible light spectrum, meaning blue light would penetrate the farthest through water.

However it’s used, bioluminescence in the animal world has purpose. In the ocean, bioluminescence can lure food, attract a mate, and warn off or make your shape visually confusing to predators. There’s a species of shrimp that sends out a cloud of blindingly bright goo in a last ditch effort to get away from whatever is trying to eat them. On the other side of the predator/prey relationship, the angler fish dangles his little “lantern” like a lure to draw his prey closer to his mouth.

Insects have both uses for their glow too. The nighttime flash of the firefly is meant to attract a mate. This summer, pay attention to how many times the fireflies flash. If a firefly flashes his light twice, it will attract a two-flash species. If a firefly flashes three times, that’s meant to attract a three-flash species. But there’s an interesting tidbit of firefly bioluminescence that’s worth adding here, there are predator fireflies out there who mimic the flashes of other species. They use their bioluminescence to trick, capture, and eat those unsuspecting fireflies who are just trying to get on with the mating business. It adds a whole layer of drama to a warm summer night, doesn’t it? What a wondrous world we live in.

**Luciferin was named for the fallen archangel Lucifer. The name means bringer of light.