Which glowworm species lights the Waitomo Glowworm Caves in New Zealand?

The glowworm species that lights the Waitomo Glowworm Caves in New Zealand is Arachnocampa luminosa.

Despite its common name, this animal is not a worm or a firefly. It is the larval stage of a fungus gnat in the fly order Diptera, endemic to New Zealand. The larvae produce a blue-green glow that attracts small insects toward sticky silk fishing lines hanging from cave ceilings.

The species was formally described in 1891, initially under the name Bolitophila luminosa, before being moved into the genus Arachnocampa in 1924. Its Māori names include pūrātoke and titiwai; the latter refers to lights reflected in water.

Waitomo is famous for its dark, humid cave chambers, conditions that help the larvae maintain their silk snares. A common mix-up is with Australian glowworms, which belong to related Arachnocampa species, including Arachnocampa richardsae and Arachnocampa flava.