A Stunning Underground Galaxy of Glowworms

The Waitomo Caves in New Zealand boast a unique, luminescent display of glowworms – and some killer acoustics to boot.


Rachael Funnell


Rachael Funnell

Digital Content Producer

Rachael is a writer and digital content producer at IFLScience with a Zoology degree from the University of Southampton, UK, and a nose for novelty animal stories.

Digital Content Producer

Two people stand looking up at the ceiling of a cave, which is covered in glowing blue dots.

Standing above, you’d never know that below lies a complex system of caves and streams with ceilings lined with a galaxy of glowworms.

Image credit: MarcelStrelow/iStock 

This article first appeared in Issue 13 of our free digital magazine CURIOUS.

Did you know that one of the best places on Earth to enjoy opera is inside a cave? It sounds weird, but it’s true: the acoustics of New Zealand’s Waitomo Caves are off the charts. That’s why, back in 2021, an intimate performance by celebrated Kiwi tenor Geoff Sewell was held inside the tallest chamber of the cave system, which is known as “the Cathedral” for its famous resonation.


Waitomo is also known as the glowworm caves, and the light show is arguably just as arresting. Its ceilings glitter like a biological galaxy made up of thousands of the glowworm Arachnocampa luminosa, which is unique to New Zealand.

As the larvae of fungus gnats, these insects undergo a considerable glow-down when they develop into adults, but glow throughout their glory years. During this time, they enjoy damp areas of forests, streams, and a good ol’ wet cave. This is why their Māori name is “titiwai”, meaning “projected over water”.

Like other glowworms and fireflies, A. luminosa is capable of creating bioluminescent displays of green and blue, but it wasn’t until 2018 that scientists actually pinned down the chemistry behind the phenomenon.

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Researchers isolated and characterized the molecular components of the glowworm’s luciferase-luciferin system.  This revealed the purified luciferase enzyme is in the same protein family as firefly luciferase, but its substrate is entirely different. The discovery demonstrated how this glowing gold dust has evolved independently from the same family of enzymes to produce light, even if it involves using structurally different luciferins.


But enough chemistry, what about those sexy caves? 

Waitomo is divided into two levels, with the upper half being dry and full of delicate cave formations formed over 30 million years. Meanwhile, the lower half is a complex system of water-filled stream passages filled with glittering glow worms that eventually lead to the tallest chamber in the cave: the Cathedral.

While the glowworms work hard, complex cave systems work harder, and navigating Waitomo can be difficult and slippery. It’s therefore not recommended you venture into Waitomo alone, but there are plenty of tours that will guide you through this other-worldly experience.

CURIOUS magazine is a digital magazine from IFLScience featuring interviews, experts, deep dives, fun facts, news, book excerpts, and much more. Issue 16 is out now.


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  • bioluminescence,

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  • glow worms,

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