Glow Worms

Glow Worms

 By Gary Opit

For 20 million years, multiple creeks have been cascading down the slopes of the remnants of a massive extinct volcano, Wollumbin, also known as Mount Warning. After these creeks had eroded multiple valleys out of the lava flows, it was colonised by the rainforest, which at that time covered 85% of the Australian continent. The glow-worm, a stealthy carnivorous prehistoric insect, was lurking in that rainforest and lived by imitating the Milky Way galaxy around which our planet and solar system spirals.


The Byron Glow Worm is the larvae of a tiny fly, a fungus gnat. Most of the world’s fungus gnats are weak fliers that feed on fungus growing on soil, though our fungus gnats prey on other small flies. Living in caves, earth embankments and rock over-hangs this insect had learnt to burn off its waste and produce a tiny cold light at its rear end of the larvae that imitates the stars above. This process, called bioluminescence or living light, attracts tiny night flying insects. Flying up into the sky to navigate by the stars, these insects find that they have mistaken the real stars for a deadly trap.


The glow-worm has been successfully imitating the Milky Way galaxy for perhaps one hundred million years. For millions of years, it dwelt in dinosaur-haunted forests on the ancient southern continent, now known as Gondwana, of which Australia formed a sizable portion. As this rainforest-covered continent broke up, dragged apart by the unrelenting flows of liquid rock beneath our feet, an Australian-sized continent, Zealandia,lying to the east of us, was the home of countless animals and plants until it sank beneath the ocean waves 28 million years ago leaving only its highest mountains above the ocean, the islands of New Zealand and New Caledonia,isolated in the Pacific Ocean. During that time Australia drifted north, the continent dried, the rainforest retreated to the wet eastern coast and on these three landmasses, the glow-worms continued to thrive in the dark recesses of forested mountains.


An ancient population of these wonderful insects still survive in an alpine cave on Mount Buffalo in Victoria, related to the glow-worms in Tasmania and New Zealand. Additional species of glow-worms dwell in caves and rock overhangs along the eastern coastlines of New South Wales and Queensland. Because glow-worms live in such remote places, most people live their whole lives unaware of the miraculous insect imitating the stars.


The Byron glow-worm is endemic to New South Wales and its scientific name is Arachnocampa richardsae. The name 'Arachnocampa' means 'spider grub'- a reference to the web of silk threads that glow-worms use to capture prey. Our glow-worm prefers a relatively warm temperature of around230C and suspends itself in a 'web' of sticky silk threads known as a 'snare', made up of a mucus tube, in which the glow-worm resides, bracing threads, which suspend the glow-worm from its substrate, and 'fishing lines', which hang vertically beneath the mucus tube. The fishing lines, studded with globular secretions of mucus, immobilise insects that blunder into them.

When night falls, glow-worms lure insects into their fishing lines using their bioluminescent taillight. The blue-green light is produced by a chemical reaction between lucifer in - a waste product produced by the glow-worm - and the enzyme luciferase, in the presence of oxygen and a form of energy known as ATP (adenosine triphosphate). When an insect is caught, the glow-worm reels its catch upwards using its mouth parts, and attaches it to the mucus tube to prevent escape.

The adult does not eat and because they are poor fliers, they usually mate as soon as they emerge from their pupal cases. Mating can last for more than seven hours, and females lay their 130 eggs near the colony, and she dies shortly after. Eight or nine days later the larvae hatch and because they are very sensitive to cold, dry conditions, they establish themselves near tiny cracks or seepage spots, which they can retreat into if conditions deteriorate.The glow-worm larvae are four centimetres in length and live between five and12 months. When a larva is ready to pupate, the mucus tube hardens around it and the adult develops over about seven days.

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