Whose signature is this?
And who has left this one?
The colour is a clue, as is the black background – and the season.
These are trails you might be lucky enough to see if you go out into the forest late on a summer night – about an hour after sunset.
That’s right! They are the signatures of fireflies, lightning bugs, or glowworms – whatever name you know them by.
Above are two parts cropped out of the following photo I took in the forest outside Brussels, Belgium, a week after the summer solstice.
The oldest known fossils of the Lampyridae family – that are characterised by their ability to produce light by bioluminescence – are from the Late Cretaceous, 99 million years ago (ref). On this ‘Life of Earth in a Year‘ timescale that’s 3 days ago, at the same time as the appearance of flowering plants on land. So there was extra colour at night as well as during the day for the delight I imagine of the dinosaurs, mammals, amphibians and birds that were around.
Luckily for these beetles (and us), they survived the fifth and most recent mass extinction event 66 million years ago. Three quarters of plant & animal species were not so lucky.
Here’s another shot I got of them, with a close fly-past on the top right.
What can you see in these photos? Let me know in the comments section at the end of this post.
There are more than 2,000 described species of these beetles in the Lampyridae family. I didn’t try to catch one so I have no idea which species we get in Belgium!
With nature putting on such a show, it’s no wonder that our folklore contains night-time spirits: will-o’-the-wisp in English, ignis fatuus in Latin, feu follet in French, Irrlicht in German, to list just a few translations.
It’s a wonderful spectacle – even more captivating because they are totally silent. This gives a magical atmosphere to the forest as the last faint glow from the sunset fades.
“Glow baby, glow!”