Fungus Gnat

• GeneralIts larvae light the Waitomo caves blue and hunt with sticky threads of silk.
• The larva regulates its glow according to how hungry it is: the longer it goes unfed, the brighter its light.
• The adult has no functional mouthparts: it lives barely a few days, solely to breed, and dies without eating.
• It is not a firefly but the larva of a fungus gnat, and it is endemic to New Zealand; its genus exists only there and in Australia.
• It fishes with lines. It weaves a silk nest on the cave ceiling and hangs up to thirty threads from it, dotted with droplets of sticky mucus. The blue-green light attracts flying insects, which get caught in the threads, and the larva hauls them up by swallowing the thread itself.
• The hungrier it is, the brighter it glows: well-fed larvae dim their light and hungry ones intensify it to attract more prey. The most impressive displays in the caves are, in reality, larvae going hungry.
• It is territorial and cannibalistic: if two nests end up too close together there are fights, and mature larvae keep about 10 or 15 cm apart.
• The adult lives a very short time: about 76 hours for the female and about 96 for the male. It does not eat, has no functional mouthparts, and its only task is to reproduce.
• The Waitomo caves have drawn as many as half a million visitors a year, and their climate is actively managed: in the 1970s an open entrance turned the cave into a wind tunnel and damaged the colony.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Limestone caves and damp ravines

Sources consulted: Meyer-Rochow (2007), Luminescence; Broadley y Stringer; Merritt (2024), Austral Entomology; Pugsley (1984)

The pins mark the parks where its presence is documented.