Glow Worm Facts
Glow Worms are pretty fascinating animals! Sometimes known as fireflies or lightening bugs, they are not worms at all. They are actually adult beetles, or their insect larvae (maggots). The largest colony is found across Australia and New Zealand with 8 known species. The Glow worm population is a unique and special part of our ecosystems.
Glow worms live in dark, wet environments, preferably in glowworm caves if they can find them, although on the Gold Coast of Queensland they don't have any caves to live in, so the local species, Arachnocampa flava are usually found beside waterfalls.
What are Glow Worms?
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.
Description of the Glow Worm
Glow worm larvae have segmented bodies and six legs at the head end. When they move, they often use their tails to help them, which makes them look very similar to caterpillars. The adult males are medium-sized insects, segmented and elongated, often with long antennae.
The females often look very similar to the larvae, but in many species they are more flattened than the males and do not have wings which means they're unable to fly. In both the larvae and adults, the light-producing organs are in the last few tail segments of the body. Both larvae and adults can be a range of colors such as black, brown, yellow, green, or red.
Reproduction of the Glow Worm
To reproduce, the female bends her abdomen upwards showing her glowing organs to attract males, which fly about a meter above her.
Each adult female lives for only a few weeks until she mates. After laying around 75-100 glow worm eggs in the ground, the female soon dies. The eggs hatch into larvae after a few weeks and remain as larvae for 1 or 2 summers. There can be a approximately 2-3 year gap between mating and the appearance of adult glow worms.
Why Do Glow Worms Glow?
Glow worms have a luminescent glow called bioluminescence or glowing light, 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.
How Do Glow Worms Glow?
The light of a glow worm is also known as bioluminescence or light produced by a living organism. There are many different animals which have bioluminescent properties including:
- Fireflies, glow worms and other insect larvae
- Arachnids (spiders)
- Annelids (ringed worms)
- Some deep-sea fish and squid
- And certain varieties of bacteria and fungi
The light Glow Worms 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 our cave.
All images on this page are copyright to Anthony O'Toole. Written permission must be gained before use.
* ATP molecules are found in all living cells. ATP molecules make any energy consuming actions (running, jumping, moving fingers etc) possible by storing the energy obtained by food and releasing it when needed. ATP is a necessary part of the reaction needed to create the light a glow worm produces