Pūriri moth

The pūriri moth is easily identifiable by its large size and vivid forewing colouration. Adults exhibit sexual dimorphism. With a wingspan that averages 100mm (for males) and 150mm (for females), it is New Zealand's largest native winged insect. The forewings generally exhibit a range of bright greens, with patterning of brownish black in females and a white pattern in males. The hind wings are a pinkish colour. There is colour variation within the species, with some individuals exhibiting blue-green, bright yellow, brick-red or even albino wing colouration. The moths are nocturnal forest-dwellers. In the past males frequently swarmed lights in areas inhabited by people - early settlers reported great swarms of the moths "invading rooms, sufficient in number to extinguish lighted lamps". However with forest clearing, this has become less common. Pūriri moths are predated upon by birds, including kākā and moreporks (who tend to feed on the adult moths when they congregate around lights), native bats, cats, and brushtail possums. The larva also are traditionally eaten by Māori, who flushed the caterpillars (known as ngutara) out of their tunnels with water.

The caterpillar stage may last up to six years. The adult moths emerge mostly from September through to November. Adults live only a few days at most, generally being most active at dusk and night time when they mate and lay eggs. The adults do not have any mouthparts and cannot feed, so are sustained only by larval food reserves.

The female moths oviposit around 2000 eggs during their adult lifetime. The eggs are randomly laid on the forest floor. The eggs are initially yellow-white, and darken to black, before hatching (normally after about 2 weeks). Initially the larva live under decaying wood close to the ground where they feed on bracket fungi. After about a year of living on the forest floor, the larva move into their host tree, and construct a burrow in the growing trunks and limbs of their host plants. This tunnel is often described as seven-shaped. Approximately 13mm in diameter it penetrates into the tree approximately 40-50mm and then runs perpendicularly down the tree for around 150mm at its largest. The tunnel is gradually expanded as the larva grows and moults. The tunnel is protected and camouflaged by a covering web constructed of silk and wood chips.

The larva emerges at night to feed on callus tissue around the entrance to the burrow, where it is hidden under a camouflaged web of silk (often matching the bark in colour and texture). …