Glowing bugs: which insects really make their own light?
The creatures in Glowing Bugs are drawn as if lit from within, but most of them make no light at all. A few do, and four of them are in the book.
The Glow-worm, Lampyris noctiluca, is not a worm but a beetle. The female holds a steady light under the last three segments of her body for hours each night, and her light is the most efficient known in nature: about 41% of the chemical reactions yield light, with very little lost as heat.
The Blue Ghost Firefly, Phausis reticulata, does not flash. The male keeps his light on for a minute or more as he drifts through the forest, leaving long, pale trails. The light is closer to green, but to our eyes in the dark it looks blue. Blue Ghosts live only in the undisturbed leaf litter of old, damp forests.
The Click Beetle, Pyrophorus noctilucus, has the brightest light of any insect. People in the Amazon once carried them in pierced gourds as lanterns.
The Railroad Worm, Phrixothrix hirtus, carries a red light on its head and eleven pairs of yellow-green lights along its sides, like the lit windows of a train. Most insects cannot see red, so it hunts by a light its prey never notices.
Each of the four has its own page on this site, with its plate, its facts and where it lives.