Glowworms (Arachnocampa luminosa)

One of my adventures while in Auckland was visiting the glowworms in the Waitomo Caves. Many of New Zealand's caves are known for having these magnificent creatures on their ceilings, lighting up the dark like stars.

Magnificent views of the glowworms

These glowworms are actually the larvae of the Arachnocampa luminosa fly- an insect found nowhere else. Adult flies lay eggs on the ceiling of the cave or undercut bank. Hatched larvae cast out fine dangling threads of silk, each with a chain of mucous droplets.

You can clearly see the droplets of mucous along the threads of silk in this picture

As insects fly towards the light of the glowworms, they get caught in the sticky threads and become their dinner. The hungrier the worm, the brighter the glow, so the more likely it is to attract a victim. The glow is the result of a chemical reaction that involves luciferin, the substrate; luciferase, the enzyme that acts upon luciferin; adenosine triphosphate, the energy molecule; and oxygen. It occurs in modified excretory organs known as Malpighian tubules in the abdomen. The larvae are sensitive to light and disturbance and will retreat into their nests and stop glowing if they or their snares are touched. Generally they have few predators. A species of harvestmen is known to prey on the glowworms in some caves. A fungus also affects the species; it gradually kills the larva. Fungus spores are spread by air movement, but since the larvae live out of the wind the spread of spores is limited. The greatest danger to glowworms is from human interference through habitat destruction.

Glowworms are found in both the North and the South Island and are generally widespread, although populations are isolated due to the lack of suitable habitat in areas where farming is intense and forests were cut down. The Waitomo Caves in the North Island and the Te Ana-au Caves in the South Island are the best known habitats, both caves having become popular tourist attractions.

Adult New Zealand glowworms do not feed and live only a few days! Both male and females grow but not nearly as bright as the larvae. Adult insects are poor fliers and so will often remain in the same area, building a colony of glowworms.

I explored the Waitomo Caves by black water rafting through them. I don't have any pictures but it is basically sitting on a round tube like the ones you go down a hill in during the winter, but through the water and rapids in the underground caves! It was so cool and fun to do, especially with the beautiful view the glowworms gave us. We even jumped backwards off some waterfalls- so cool! We were in wet suits and boots and everything but I was still FREEZING as my hands were not covered. It took me awhile to warm up! Here are some pictures of it from google (not me but similar ideas). Keep in mind it was no where near that bright in the caves, it was pitch black other than our tiny head lights!