Glow worms – they’re lit af
During the day, it is hard to know they’re around, but by night, they showcase a spectacular light show, like a little city.
But why do glow worms, glow?
Well first of all, glow worms aren’t even worms at all. They are the larvae of an insect only a few millimeters long called a fungus gnat. So they’re essentially maggots with a glowing bum, but despite their small size, they are actually pretty ferocious.
They build a silk chandelier-like web, called a snare, which consists of a mucus tube where the glow worm hangs out, bracing threads to keep the tube suspended, and fishing lines, which hang vertically and surround the tube. These fishing lines can reach almost half a meter in length and are studded with mucus beads to immobilise insects that fly into them.
They use their light to attract night-flying insects, which the larvae feast on when the insect gets entangled in the fishing lines. Despite how fragile the webs look, insects as big as cockroaches and beetles have been found in them!
Glow worm in special web (Image via Flickr)
So what makes their bum glow?
The ability of plants, fungi or animals to glow is called bioluminescence, which means ‘living light’. After a glow worm eats its prey, it absorbs the nutrients. But because a glow worm does not excrete waste, it turns the excess matter into light, which begins the cycle all over again. The blue-green light is created by a chemical reaction between a waste product they produce called luciferin, the enzyme luciferase, oxygen, and an energy molecule called ATP. So glow worms consume, but leave nothing but heat and light behind.
Where can you catch a glimpse of these starry nights?
Glow worms like shaded, protected areas with high humidity such as caves, under rocky overhangs, and along creeks and walking tracks. The best places to see them are in Australia and New Zealand. One of the most well-known places for seeing glow worms is at the Waitomo Caves in New Zealand, which is where I first laid eyes on them. To give you an example of how popular they are, the Springbrook National Park’s Glow Worms Cave in Queensland attracts over 300 tourists per night!
But research has found that these little engineers are sensitive to disturbances such as torchlights, smoke from cigarettes and fires, or something touching their web. If disturbed, they will turn off their light and retreat into a crack. Hence, it is important to remain on designated walking tracks to prevent accidentally stepping on them or disturbing them and to protect the habitat of their prey.
Glow worms are not unique in their ability to produce light internally. Many creatures have bioluminescent characteristics such as some fungi, earthworms, plankton, deep-sea marine species, and fireflies. However, scientists remain in the dark about why all of these species have this capability. Perhaps this will be illuminated in the future, but for now it is worth setting your eyes on these dazzling sites.