The world I am creating is in a swamp that contains larger than life bugs; this includes fireflies. What I ask is, could the bioluminescence of their glow somehow be harnessed or used as a light source?

More Info:

  • The fireflies are around the size of a human (about 5ft 5inches).
  • The people are more on the primitive side as they don't have the modern technology we do, and their main source of light is through fire.
  • They have basic metal and clay skills to make pots or handing lamps; they can also make a very basic form of glass.
  • $\begingroup$ Insects can't grow to the size of a human, for a lot of reasons. 6 inches would be a realistic practical limit. $\endgroup$ – jamesqf Jul 6 '19 at 5:10
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    $\begingroup$ @jamesqf It is called suspension of disbelief. Just like most science fiction has sound in space and no one questions a cyborg space-wizard (Darth Vader). The story is based on certain factors, and the question at hand isn't about "can my insects be this size", we have to assume that yes they can be this size. The question is "Could mankind use a small-human sized firefly as a lightsource". $\endgroup$ – Demigan Jul 6 '19 at 15:51
  • $\begingroup$ Fireflies? Normal ones no, but people have been harnessing the bioluminescence of other stuff for quite a while. There was some sort of beetle, I think, that was used as a "flashlight" by soldiers. It emits light that is faint enough to not be seen at a distance by enemies and bright enough to read a map or orders in the middle of the night. You'd need to hold the beetle close to the paper as the light is about comparable to a match but since it's not open flame, it won't accidentally burn anything, either. $\endgroup$ – VLAZ Jul 9 '19 at 7:06

(I edited this answer; instead of clay batons, now we have a "clay sheet". The reason is that sheets have a bigger surface and actually would be more practical than several batons)

I think they could do it.

First of all, I'm not an expert in biochemistry or anything like that. I just made some research, got some names and reactions, and assumed we have some creative license here.

About the reaction

The bioluminescence in fireflies is created by the reaction of:

  • luciferin, a chemical present in the fireflies;
  • oxigen, that will react with the luciferin;
  • luciferase, an enzyme which acts as catalyst (and thus is not consumed by the reaction).

Basically, to create light, you need to create a reaction between the oxigen and the luciferin. That won't happen by itself, and that's why luciferase is on the list: it will catalyze the reaction and make the reagents release energy, making stuff glow.

Getting your ingredients

(Again, I'm nowhere close to be an expert in (bio)chemistry, so I'll use some artistic license we have in fantasy/science fiction)

The source of the oxygen will be the air itself.

The source of luciferin and luciferase are the fireflies. You can invent the process you want to get them, but I'll guess mashing the insects with the right materials will make the thing and conveniently "trap" the chemicals you want.

An example of process could be:

  1. Getting the luminescent organ from a firefly;
  2. Envelop it in a convenient kind of clay that will trap the luciferin;
  3. Put them inside a recipient filled with a convenient oil or liquid (so there will be no air to generate the reaction);
  4. Mash your clay + luminescent organ until you're sure you have just a little luciferase in your mash;
  5. Remove the mash from the oil. It may glow a little, but since you are a very dedicated person, the reaction will be brief;
  6. Continue mashing the clay out of the oil until it stops glowing;

In the end, we'll have an oil containing luciferase and luciferin trapped in the clay. Of course, this is only for the convenience of crafting the lamp, what comes now.

The lamp

To make the lamp you want, you'll make a "sheet" of clay (not sure if it's the name of the object, but it's a rectangular flat piece of clay), that you'll put inside the lamp. Maybe it needs to dry to get firm.

The lamp can be made of wood, metal, or even glass. It would be similar to a common lamp you carry around, with holders to put the sheet in. It also has two little recipients: one on the top of the lamp and one in the bottom. If you opt for a "closed" design, it needs to let in some air.

The recipient on top will be filled with the oil you mashed the clay in; it will need some kind of mechanism to control the oil flow. The oil, as you may guess, contains luciferase and will flow on the clay sheet, creating the reaction. The flow mechanism lets you select how much of the sheet you want to light.

The recipient at the bottom will be used to capture the oil that will flow in your lamp, since luciferase is not consumed by the reaction and could be reused.

To make the lamp work, you'll have to:

  1. Put a new sheet of clay inside the lamp;
  2. Fill the upper recipient with oil;
  3. Open the mechanism and let the oil flow along the sheet; the oil will make the luciferin in the clay react with the oxygen in the air, making it glow (open more to light a bigger surface of the sheet and get a brighter light).
  4. Change the clay sheet when the reaction ends(luciferin will be consumed, so this sheets are kinda like batteries);
  5. Collect the used oil to reuse it.

And basically that's it. I've made some sketches, I hope it helps you to visualize the idea. A scheme of the lamp. First view doesn't show the side supports

A zoom on the top of the lamp and how it works

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Firefly lanterns are a thing.

Even children can do it!

Put any males that arrive into your lantern. At least 40 fireflies per lantern should give you plenty of light. Release them, unharmed, the next day.

enter image description here

With your humans and fireflies about the same size, one firefly will give enough light for a lantern's worth. A handful around an encampment should be plenty for the night. Entice them and care for them and feed them well so they'll stay voluntarily. Your community can capture them and put them on a harness if they want, but voluntary is always nicer.

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    $\begingroup$ in some species the females are flightless so you could keep them on a leash. Note however many are predators so a man sized firefly would be quite dangerous. $\endgroup$ – John Jul 6 '19 at 2:53

A typical North American firefly is 5 mm long and produces 0.3 lumens of light for a brief moment, ~300 msec.

If the bug was scaled to a length of 5 1/2 feet, and the rest of the biology scaled proportionately, then the man-sized firefly would produce 96 lumens. This is equivalent to a 7-watt bulb or a ~1 W LED light. So it would pulse like a bright candle.

I think it could be used as a navigation aid. Or lighting a shaft for miners, who are used to working in the dark due to the cost of candles. They'd move around the mine shaft by striking the stone walls with their picks to generating sparks to see for a split second. So one of your creatures would be welcome and might make the miners more productive and less prone to errors and injuries.

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