Getting ready by stealth so the creepy hostel owner would not see us leave back fired, the guy is everywhere. Fortunately we got away without having to give him a step by step account of what we planned to do today and was on our way on what was going to be a very long day in the car with the magical Waitomo Glowworm Caves to break up the drive.

The cost of entry is £25 per person, which on a backpackers budget is quite steep but it’s well worth it and should not be skipped. The tour starts the same as any other cave starting tour, when it was formed, who discovered it, how they discovered it, what’s a staligmight, staligtich, how do they form etc. If you have been backpacking any length of time you are probably sick of caves, we have been on way too many cave tours and sounded like know it alls when he was asking all his question and we was answering in rapid fire succession.

Once you are passed, what i think is just “fluff’ to justify the price, the guide will finally start talking about the glowworms, which are not worms at all but the larvae / second stage in a four stage life cycle of a mosquito, but don’t worry, these mosquitoes are born without mouths so can’t bite you. The glowworms in the Waitomo caves are called arachnocampa luminosa, ‘Archno’ means spider-like and is to represent how they catch their prey by dangling sticky silks underneath them, “campa’ means larva and ‘luminosa’ because they glow.

The tour starts to get interesting as you are lead down on the a suspended platform and the lights are turned out. Apparently the platform was only built to hold 14 people, but today we had about 50 so it was a little cramped. The fact that the platform had no other exits and there was no glowworms in sight we wondered what we was doing. It all became clear when he told us to bend down and look under neath a shelf in the rock. There were hundreds of glowworms and you was able to get up quite close and see all the silk strings dangling down that they use to catch their prey. We even got to see this in action as a fly flew by and was instantly paralysed when it hit the strings.

It was then time to get on a boat and take a journey through the caves. You have to be very quiet as the glowworms can self terminate their light if the noise gets too much. We was even told that one guy took a photo with his flash on and wiped out thousands in an instant so it’s strictly no photography. The boat ride through the pitch black cave system is what you see on all the marketing but what you see on paper cannot compare to how it looks when you are actually their under a blanket of organic stars. It’s over almost to quickly and your eyes burn as you see the daylight up ahead but you have definitely made a memory of a life time and may not see anything like it again.

The four stage lifecycle

Eggs are the first stage of a glowworms life cycle, they take about 3 weeks to hatch leading to the second stage, larvae. Whats scary is that only a handful out of a 120 eggs ever get to the larvae stage because the first ones to hatch start eating the others, yuck. Once the newly hatched larvae have run out of brothers and sisters to eat they build a nest, lower silk like lines and start to feed on anything unfortunate enough to fly into the sticky lines. Once the larvae has caught something, it is drawn up and ingested. From as soon as the larvae hatch they emit a light and over 9 months slowly form from 3mm to roughly the size of a matchstick.

Once the larvae has enough resources it spins a pupa, similar to a cocoon, and suspends itself from the ceiling for 13 days whist it’s metamorphosis takes place and goes in to the final and shortest stage of its lifecycle, adult hood. As an adult their only function is to reproduce and continue the line of succession. The males are usually waiting outside the pupa of females so as soon as they hatch mating can commence and the cycle begins again. The adults are born without a mouth and die of starvation after only a few days.

glow worm life cycle

How and why do they glow

A glowworm glows thanks to bioluminescence. The larvae has a special organ that releases certain chemicals that react with the oxygen in the air and light is produced. The larvae can actually regulate how much light it’s giving off by reducing and increasing the flow of oxygen to the organ.

The glowworms glow for three reasons. The first is probably the most obvious, to attack prey in to their sticky snare enabling them to grow and move on to the next stage in the life cycle. The second is to ware off predators and the third, which I find the most interesting, is to burn off their waste. This is a good thing as you would not want glowworm poop falling on your heads when you are in the cave would you?

Other interesting facts about the cave system

As you are on the tour the guide does give you some interesting facts. The most memorable was that there was once only 24 glowworms in the cave due to excessive tourism, they had to close the cave down for a long time whilst the population regrew as a result. They even had to bring in glowworms from other caves to bolster the numbers. Another thing of note the guide mentioned was how the highest point in the cave (the cathedral) is a natural amphitheatre, many famous visitors have stopped to sing there and a handful of people have even used it as a wedding venue.

Hopefully you’re all glowworm experts now!