See a Night Sky Underground at New Zealand's Glowworm Caves

Intricate sign at the caves
Photo by A.Aruninta

The Glowworm Caves, or the Waitomo Caves, are amazing natural wonders located in Waitomo on North Island in New Zealand. There is a series of them with millions of glowing larvae, pupae and bugs populating their ceilings. Visitors liken the effect of these glowing creatures to that of a particularly starry night sky. In some spots, you can see glowing dots on strands that hang from above, almost like icicle Christmas lights.

The little bugs, larvae and pupae that are responsible for the decor of the Glowworm Caves are known Arachnocampa luminosa, New Zealand fungus gnats or, less commonly, glowing spider bugs. These bugs go through four basic life stages. They begin as eggs, which hatch to become larvae (during which time they molt four times), which in turn pupate. Then comes the adult. New Zealand fungus gnats begin glowing when they reach the larval stage of their development.

Arachnocampa luminosa larvae spend their days hiding in cracks and crevices in the Glowworm Caves. At night, they come out and hide in little silk tunnels they have constructed. These silk tunnels are for catching prey. They are also used as a dwelling of sorts during the pupal stage of their development. New Zealand fungus gnats spend about three weeks as eggs, six to twelve months as larvae and about twelve days as pupae. Adults come out of the pupal stage unable to eat. They have no mouths. They will only survive long enough to procreate. For the male Arachnocampa luminosa, this will be between three and five days. The female will only survive one or two days. After laying her eggs, she will sometimes stop glowing, always dying shortly thereafter.

There is no shortage of New Zealand fungus gnats in New Zealand. However, the Glowworm Caves are the most popular places to view these bioluminescent bugs. The darkness of the caves makes them a perfect place to witness the glow of the Arachnocampa luminosa.

There are literally hundreds of guided tours available for visitors to the Glowworm Caves. The caves may be entered on foot or via the Waitomo River in a raft or canoe.

Sources

New Zealand Fungus Gnat (NZ Glowworm), retrieved 9/12/16

New Zealand Travel Guide/WaitomoGlowworm Caves, retrieved 9/12/16