I recently read about a predatory glow worm that was discovered in the Peruvian Amazon. The glow worm is a beetle larva which has not yet been classified, although it is thought to be in the family Elateridae, or the click beetles.
There’s this really neat information graphic about it:
And several photographs taken by the discoverer, Jeff Cremer:
Although little is known about this glow worm (and indeed it may be a species new to science), we can take some guesses as to its business. The term “glow worm” includes a number of different families of insects, all beetle adults or larvae and fly larvae, the most familiar of which is the Lampyrids, or the fireflies. The glow worm of myths and legends is the wingless adult female of the species Lampyris noctiluca.
The fireflies glow to attract mates, and thus their bioluminescence is an example of sexual selection. But for other groups of glow worms, in particular, those that glow as larvae, there is a different cause for the light.
For the predaceous non-breeding juveniles, the production of light is a way to attract prey (kind of like that terrifying angler fish in Finding Nemo…BOO).
So we might suspect that these predatory glow worms are trying to attract prey using bioluminescence. To my knowledge, this is the only example of an Elaterid glow worm. It makes me wonder how many times this tactic has evolved and in what groups. This could shed some light* on convergent evolution!