Julia's Birds, Bugs, Bikes and Boats Blog: A Tour by Night for Children

The lights of the titiwai, or glow worm

During the school holidays Zealandia runs night tours for children. They start out slightly earlier than the normal tour but finish an hour earlier and do not go so far up the valley.
I went out as Assistant Guide one night with a group of very excited children accompanied by just as excited adults. We saw patake, kaka, kawau and baby tuatara, then turned to seeking out kiwi. Though we heard rustles we did not get to see one. The group was a little noisy and spread out which may have been a factor.

We headed up to the gold -mine to see cave weta and have a chocolate drink. The weta have shifted out of the mine at present and are making their home in a lock-up box where the helmets are kept which makes them easy to find and be observed. Makes it tricky to get the helmets out though!

A volunteer in the mine.

While this was going on I had the job of taking small groups into the mine. Wellington had a small and unsuccessful gold rush in the 1860s. Several shafts were drilled about the place including a couple in Zealandia. The mine we were about to enter was the Morning Star Mine, a shallow tunnel of about fifteen metres or so in length. Rail tracks can still be seen curving out of the entrance. Trucks of quartz bearing rock was carted down to the river to be crushed, but nothing was ever found and the mine was quickly closed.

Kids in the mine - or in the middle of Middle Earth. Spot the cave wetas on the wall.

As our tour was tailored for children we did not go in too far, just enough to get an idea of being inside a tunnel. At this point I asked everyone to turn off their torches. There was a collective gasp as above us a myriad of tiny blue lights twinkled brightly. The children were entranced. After a moment I suggested they could turn their torches on again and look at the little creatures which were producing such a bright light.
The glow worms were putting on a brilliant display. During the dry summer there had always been glow worms throughout the valley but in limited numbers, even inside the mine. Now after rain they were returning to their best, putting down little fishing lines and glowing for all their worth.

Glow worms are not worms at all. They are the larvae of the fungus gnat. They set up home under damp banks and in caves. Glow worms are carnivores and put down silk fishing lines with sticky beads to catch their prey.Their glow is produced from a modified kidney at their rear. Many insects have this organ but glow worms are unique in their ability to produce a cold blue/green light from it. This lures small insects which then get caught in the sticky threads. The glow worm hauls up the thread and eats the victim.
The Maori called them titiwai, referring to the fact that glow worms congregate together making them look like a little fishing village with lights reflecting off the water.

Not all children ventured in but those that did saw a great display.