Waitomo is world famous for the Waitomo Glowworm Caves and more importantly the New Zealand glowworm.
What is a glowworm? A glowworm is the larvae stage in the lifecycle of a two-winged insect. It grows as long as a matchstick and looks a bit like a maggot. The one unique to New Zealand is arachnocampa luminosa. ‘Arachno’ means spider-like, which refers to the way glowworms catch flying insects like spiders do. ‘Campa’ means larva and ‘luminosa’ means light-producing.
Why & how they glow: A glowworm uses its glow to attract food and to burn off its waste. It’s tail glows because of bioluminescence, which is a reaction between the chemicals given off by the glowworm and the oxygen in the air. This chemical reaction produces light, which the glowworm can control by reducing the oxygen to the light organ. Insects fly towards the light and get stuck in the sticky lines that the glowworm hangs down to catch food. Glowworms also use their glow to put other creatures off eating them.
Why they are found in caves: Glowworms can survive only in very damp, dark places where their light can be seen. They need a ceiling that is fairly much horizontal from which they can hang their sticky feeding lines, and a sheltered place where wind does not dry them out or tangle their lines. The Waitomo Glowworm Caves provide a perfect environment with an abundance of insects brought into the cave via the river.