Ruakuri Cave

Today we toured there Ruakuri Cave. The name Te Ruakuri, or "The Den of Dogs" was given to the surrounding area when wild dogs were discovered living in the entrance of the cave about 400-500 years ago. A river flows through the cave, but we entered in through a man made spiral entrance. The natural land entrances was used by Māori as an urupā or burial site. As a sacred area it is no longer used for tourism. This spiral and the boardwalks inside the cave make it wheelchair accessible, the only one in the southern hemisphere! This cave had the usual limestone cave formations — stalagtites, stalagmites, columns, popcorn, scallops, curtains, etc — all very beautiful. But the highlight was the glow worms. Although the glow worms weren’t as abundant as they were 3 years ago (pre flood) it was a very cool sight!! Arachnocampa luminosa, or the New Zealand glowworm, is the larval stage of a fungus gnat. It produces a captivating blue-green bioluminescent light, where in large numbers, look like starry night sky and attracts prey into its sticky silk traps. The life cycle of the glow worm, like most insects, has four stages: Eggs: A female fly lays around 130 small eggs. After around 20 days, the young larvae hatch from the eggs. Larva: Having hatched, the larvae build a nest, put lines down and feed. The lines are coated with sticky substances. It is this sticky coating which traps insects. The lines are then drawn up and the insects eaten. It is the larva that emit the light in order to attract the insects to the lines. They live as larva (with 5 instar stages) for about 9 months. Pupae: In the pupae stage, a cocoon like structure is formed and the larva transitions to its adult form over 12-13 days. Adult: They then emerge as adult fungus gnats. The females are much larger and emit a special “mating” bioluminescence. The males can fly weakly and will mate with as many females as possible in its short 6 day life span. Females generally mate immediately after emergence and fly very weakly. Females live 2-3 days and die after egg laying. Neither sex adult forms have functional mouth parts and do not feed as adults.