Satisfy your kid’s curiosity about the glow worms with the details that may surprise her – like the fact that a glow worm is not even a worm; it is a beetle!
Glow Worms are the larvae (immature stage) of a small fly. The larval stage is the only stage in their life cycle that can glow. The adults are delicate flies that do not have working mouthparts, and as such, only live for a small number of days (females two days, males six days).
As the adults are unable to feed, Glow Worms must gain enough sustenance during the larval stage to get them through the rest of their lifecycle. The larvae are believed to live for approximately one year, although this is heavily dependent on environmental conditions and availability of food.
Below are some interesting facts you probably didn’t know about Glow Worms:
1. Glow Worms glow to attract small insects that emerge from the leaf litter and water to where the Glow Worms reside. The Glow Worms construct “snares” (like a spider’s web) made from silk threads and sticky droplets to capture and eat the insects attracted to their glow, which they then feed on.
The light of a glow worm is also known as bioluminescence or light produced by a living organism. In the case of glow worms, the light they emit is produced by a chemical reaction. A pigment called “luciferin” reacts with the enzyme “luciferase” and adenosine triphosphate (also called ATP*) and with the oxygen in the air to create the blue-green light that you see the glow worms emitting in the glow worm caves.
2. Ancient civilizations were fascinated with the glow worm, thinking the insects were magical because of their ability to light up. The tiny beetles appear in poetry and fairy tales as mysterious or supernatural beings, and history books reveal that early doctors even tried to capture glow worms’ powers by using them in medicines.
Legends claim that people used glow worms to line walkways and light their homes. Thousands of years later, a child’s toy was modeled afterglow worms. Unlike the real insect, the toy’s head instead of the tail would light up when the body was squeezed.
3. The glowworms found in the Waitomo and Ruakuri caves are the larvae of a species of gnat called Arachnocampa Luminosa, which is unique to New Zealand. These insects spend most of their life as larvae (juveniles), growing to the size of a matchstick. Although the effect of their twinkling lights is beautiful, the glowworm itself actually looks quite like a maggot!
4. Young glowworms called larvae are predatory and hunt for snails, slugs and other insects to eat. They have a predominately meat-based diet but also eat leaves and other plants sometimes; this makes glowworms omnivores. However, once they have morphed to the adult stage, glowworms rarely feed. The adults are busy protecting their young and laying new eggs.
5. The adult glow worms of Australian species don’t glow, but adult females of the New Zealand species do produce a blue light. Once hatched, the tiny larvae are capable of glowing immediately.
6. The females glow the brightest. Like mosquitoes, in which only the females suck blood, it is primarily the female glowworms that have the ability to glow. During the mating season, the female spends about two hours every night giving off a bright bioluminescent light from the abdomen and rear to attract a mate.
The male glowworms are attracted to the light, but can sometimes be misdirected by street lights and another lighting. The females survive through only a short period of a few weeks to mate and lay eggs before they die.
The adult males and larval young can only produce a faint glow to help attract the prey they need for food. The glowworms’ light is also a warning for predators such as birds, spiders, and centipedes to stay away. The bioluminescent chemicals inside them are toxic to other insects and animals.