Gerjon Dol from Norg made a very special discovery in his backyard: “It looks a bit like Christmas lights, but it isn’t. They are glow worms!” says Dol enthusiastically.
But are they glowworms, glowworms, or fireflies? None of them: they are actually beetles. There is, however, a consensus that they at least give light. You can also conclude that from the scientific name: Lampyridae. And they give that light throughout their lives, whether they are larva, egg, pupa, or hatched.
Dol thought at first that there were lights blinking in the woods behind his yard. This raised quite a few question marks and he decided to investigate further. This made Dol realize that the lights were not in the woods, but in his own garden. “I thought that it is very strange that there are Christmas lights there, because I did not hang them,” says Dol. So he went to look again during the day, but then there was nothing to see. “I didn’t understand it at all.”
There are three different types of glowworms in the Netherlands. The large glowworm is the most common of these, but you can also encounter the small glowworm and the short shield glowworm. The little glowworm is also called a firefly, because the males emit light during their flight. The large glowworm only glows when it sits still. They can fly, while the short shield firefly has no wings at all.
Dol eventually learned that the mysterious lights in his garden might be glowworms. “I thought that was a bit crazy, it’s really sixty of those lights that flash on and off completely synchronously.” Hence the Christmas lighting effect.
Dol says that a biologist has confirmed that they are indeed glow worms. “He also said that it doesn’t happen that often here in Drenthe,” said Dol. “In the past ten years, seven observations have been made, so that is not very much. Normally they are only in Limburg.”
The larva of the large glowworm prefers to eat a menu of snails. Slugs are of course the easiest, but snails are also regularly outwitted. The glowworm achieves this by injecting juices into the snail’s house. As a result, the snail withdraws and then completely softens from the liquid. The larva can therefore comfortably crawl inside and swallow the snail. Once the glowworm has changed from a larva to an adult individual, it won’t eat anything at all. They then only live on the reserves they have built up during their larval stage.
The glowworms produce light because a biochemical reaction takes place in the cells of their light organ. It’s in their abdomen. Energy is released in the form of photons – in other words, light particles. The light is usually a yellow-green color.
The adult glowworms use these lights to look for each other during the mating period. So you can only spot the luminescent glow worms for a short period of time, about a month. Dol has had them in the garden for about a month now, so the light will go out soon. Fortunately, he can always put up Christmas lights.