Monday, February 1, 2016

Day 2 (Dec 21) - Waitomo

Our second day took us on country roads into the rolling hills south of Auckland as we headed towards the village of Waitomo, a major tourist attraction famous for its glowworm caves.
Short hike in the hills surrounding the Waitomo caves

The Waitomo limestones caves are the result of geological and volcanic activity over the last 30 million years. The limestone comprises fossilized corals, seashells, fish skeletons, and other marine organisms, which have been layered over each other and compressed.

The limestone caves are similar to those in other parts of the world.  The real attraction are the glowworms.

Once the limestone was pushed out of the seabed and exposed to air it began to crack and allowed water to flow through, which dissolved the limestone and created the caves.
One of the larger stalactites inside the cave that we visited 

Glowworms (aranchnocampa luminosa) are tiny insects (gnats) – about the size of a mosquito – which can glow in the dark.  The life cycle starts with an egg, which hatches into a larva, pupates, and finally turns into an adult.

This is what happens when you turn off the light and look at the ceiling.  The glow of the larvae makes it remarkable similar to the night sky.

The larval stage is the longest of its life and lasts about 3-6 months.  At its end, the insect becomes a pupa, hanging down from the roof of the cave on a short, silken thread.

These are some of the silken threads hanging from the ceiling.  Its main purpose is to catch prey.  During the pupal stage, pupae hang at the bottom of these threads.

These threads are spun by larvae, reach a length of about 3-5 cm, and hold droplet of mucus.  The glow of the larvae attracts prey into these threads. Prey includes midges, mayflies, mosquitos, moths, or even small snails or millipedes.  When prey is entangled in the snare, the larva pulls it up by ingesting the snare and starts feeding. 

Another attempt at capturing the glow at the ceiling. The light in the foreground was emitted from the autofocus of a camera used by a fellow visitor.

The pupa stage lasts about 1-2 weeks during which the insect glows intermittently.  The increasing glow from the female is believed to attract a mate who will wait for the insect to emerge from the pupa.  The adult glowworm is a poor flyer, does not feed, and lives only for a few days, mainly to reproduce and lay about 100 eggs.  The eggs hatch after about 20 days and the cycle repeats.

It is impossible to see the glowworms when the light is switched on.

Several of the caves at Waitomo have been developed for tourism.  We picked one of smallest tour operators, which allowed us to have a more intimate experience absent the masses. We spent about half a day visiting two caves, one on foot and the other by boat along an underground creek/lake.
The streaks capture the glow emitted from the insects during a 6 second exposure while I sat in a turning raft on an underground lake, holding the cameras as steady as possible towards the ceiling.

After our visit to Waitomo we drove to Mourea on the northeast shore of Lake Rotorua where we checked into a small two-bedroom townhouse for the next two nights.

Julian at an overlook on top of one of the hills surrounding Waitomo.

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