Who said that stars glow only up in the skies?

Who said that light can't be found deep inside the darkness of the earth's guts?

On North Island (New Zealand) there are caves that ripped bits of the starry night sky and hid them underground, so that creatures which never see the light can get a... taste.

The Waitomo Glowworm Cave

Image through: commons.wikimedia.org - Courtesy of (assumingly): Markrosenrosen - License: CC BY-SA 3.0

The Waitomo Cave system consists of various formations, the main caves are: The Waitomo Glowworm Cave, the Ruakuri Cave, the Gardner's Gut and Aranui Cave. They are limestone caves that formed a long time ago (30 million years), when everything was covered by the ocean and their limestone merely consists of fossilized marine organisms (corals, small fish and seashells) that were deposited in layers one above the other. The final outcome? Limestone as thick as 200 m around the wider area of Waitomo. [3]

The caves were known to the local Māori people who named them after the words wai and tomo (water and hole/shaft). Exploration began in late 19th century (1887-1888) by Māori Tane Tinorau and the English Laurence Cussen and Fred Mace and one year later, Tinorau set up a "business" and charged visitors a small fee in order to guide them in the cave. Today guided tours for visitors are still available in the Cave System (for more information you can visit those links: waitomo.com & backpackerguide.nz). [2, 3]

Past geological activity caused the limestone to bend, rise above ocean level. Fissures and cracks were created by the contact with the air and as water started flowing in it "carved" those hollows and left behind a beautiful cave system with stalactites and stalagmites. [3]

Image through: commons.wikimedia.org - Courtesy of: Манько Марко - License: CC BY-SA 4.0

But the caves are not only known for their beautiful "interior design". It's also their inhabitants that make them famous! Arachnocampa luminosa is an endemic species of fungus gnats that lives only in New Zealand. [1, 2, 3]

Like the abysmal hunters, those glowworms (which are basically the larvae) use their eerie blue-green light as a lure for poor moths and other flying insects that try to find their way out of the caves. These insects use the moon and stars to navigate, the dazzling lights from the glowworms seem to confuse them though. They think they are flying closer to their destination. Closer. Closer. Oooo-ooh! Now they are all stuck in some weird sticky strings and they can't get out of. Fighting will only make matters worse, that gluey substance will cover their wings and keep them trapped. The strings are nothing more than silken threads the glowworms make in order to catch their prey. [1]

Once the prey has gotten tangled enough and is unable to move, the worm starts pulling the snare up and feasting time starts. The poor insect may still be alive when those sharp worm teeth pierce its body (Life is cruel, I know). The worms glow their brightest during their larvae stage (that lasts about 6-9 months), adult worms (that live for a few days) glow less and only for mating purposes. Their anatomy shows they don't even have mouths, which would explain their short life span. [1, 5]

Their light comes from... shit!

Yeap! The light they emit is an excretion byproduct. Near their anus there is an organ where the reaction of luciferase and other chemicals take place. The reaction needs a lot of oxygen, therefore an airbag surrounds the light organ to provide with the necessary oxygen (seems a lot more eco-friendly than using batteries). [5, 6]

And you wanna know something even cooler and bizarre? Those colonies even have their own circadian rhythm! This means they have a mechanism that works like a "clock" and they even follow a pattern as their light gets brighter or dimmer during the day. The hungrier the colony is, the brighter the light! [1, video]

There is more than worms inside

Besides those beautiful bioluminescent worms, you can find other creatures in those caves. Insects like crickets, and albino cave ants, along with New Zealand longfin eels also live in there. And since the caves are the perfect dark and humid place for fungi, you can come across several species of those too. [3]

Watch this awesome video to learn more about the cute shining hunters!

Don't tell me that after reading that you didn't put New Zealand on your list!!!

References

[1] kqed.org
[2] atlasobscura.com
[3] wikipedia.org
[4] unusualplaces.org
[5] waitomocaves.com
[6] nikaucave.co.nz

* If you want to learn more about bioluminescence in nature, you can check out a previous post of this series: Bizarre Natural Phenomena Vol.2 - Bioluminescence, The Art Of Creating Light

Thank you so much for your time!

Until my next post,
Steem on and keep smiling, people!