Forest ringlet butterflies are so stunning that in 1991, New Zealand put them on a postage stamp! Sadly, these endemic butterflies are currently classified as “at risk-relict,” which means today they occupy less than 10% of their original range. Since it is the ONLY butterfly in the genus Dodonidia, that means the entire genus is at risk of extinction. Although the cause of population declines is unknown, introduced predators and parasites likely play a role.
Forest ringlet butterflies lay their tiny eggs on the underside of host plant leaves (often sedges or tussock). Each time the caterpillar moults, it begins a new instar. Early instar larvae are small (~5mm) compared to late instar larvae (~35mm). As they moult into their second instar, they shed their black head to reveal a forked head and the whole body is disguised in the perfect shade of green to camouflage against the host plant leaves. If winter approaches before they have finished growing, the larvae will move to the base of the host plant (where it can buffer itself from the chill). When it is time to pupate, larvae will climb and attach to the underside of a host leaf to build the cocoon. About 20-30 days later, a vibrant adult butterfly will emerge.
Check these links for more info on the Forest Ringlet Butterfly in NZ
Wikipedia: Information on Forest Ringlet Butterfly
NZ Butterfly Info: Forest Ringlet
Moths & Butterflies of New Zealand Trust: Forest Ringlet
Click on the image to visit the official iNaturalist.nz observation.