Insects - Glow Worms & Fireflies

Both glow worms and fireflies are insects, but they are not exactly what their names suggest!

Glow worms

The glow worm isn't a worm at all, but the larvae or maggot of a mosquito-like fly. Only three glow worms have been described in Australia . Arachnocampa flava is a species endemic to Queensland. Glow worms can be found in shady, protected places with high humidity. You might find them in cuttings, creek banks, rock faces and the roots of fallen trees.

Glow worms build ‘snares’ made of silk fibres coated with mucous. The snares consists of tubes in which the glow worms are suspended, as well as long, hanging filaments coated in sticky beads of mucous. The glow worms emit a pale light which attracts insects toward the sticky threads of their snare. The blue/green light is a product of a chemical reaction between luciferin (a waste product), the enzyme luciferase, adenosine triphosphate (ATP, the energy molecule) and oxygen. The snare usually catches small bugs such as midges, but insects as big as cockroaches can be entrapped.

Fireflies

In the early evening, flashing lights can often be seen cruising around in the forest. These are the little lanterns on the underside of the abdomen of a carnivorous beetle of the family Lampyridae. These beetles have been misnamed fireflies. It is believed that the flashing light is used by males and females to attract each other. The light is created by an enzyme (luciferase) which reacts with other chemicals in the insect's body to produce light energy. The firefly regulates the emmission of light by controlling the amount of air supplied to the cells. The regularity and intensity of the flashing may help fireflies identify males and females. Both the firefly larvae and wingless females can also be also known as glow worms. The larvae of the firefly has a flat, segmented body resembling a kind of serrated flatworm. This larvae has two little 'windows' at the back end of the body through which a pale green glow is seen. Why the larvae also glows is unknown. (The ability of plants, fungi or animals to "glow" is called bioluminescence.)