bag moth carrying its silken case through the canopy

Size
Length: 1–2 cm
Lifespan
1–2 years
Diet
Larvae feed on lichen, algae and dead plant material from inside their portable bag. Adults do not feed (males lack mouthparts; females remain in their bag).
Habitat
Gardens, parks, walls, fences, tree trunks and building eaves. The architects of disguise, building portable homes from silk, lichen and debris wherever there is food or shelter.
Range
Throughout North and South Islands in gardens, parks and urban areas. Most common in warmer, coastal regions of North Island where lichen and algae are abundant.
Endemism
Introduced
Main Threats
None. This introduced species is well-established. Considered a minor pest in gardens and nurseries, but controlled naturally by birds and parasitic wasps which prey on the larvae.
Population
Originally from Australia but now ubiquitous in New Zealand. Considered a minor pest in gardens and nurseries, where large numbers can strip foliage from shrubs.
Conservation Status
Introduced
The ultimate homebody of the insect world. The female bag moth never leaves her house. From the moment she hatches, she constructs a protective case, a bag, made of silk and decorated with fragments of lichen, bark or sand grains that perfectly match her surroundings. A mobile fortress that looks like part of the tree. She drags this fortress wherever she goes, retracting into it at the slightest sign of danger. Inside this mobile bunker, she lives, feeds and eventually lays her eggs, never seeing the sky or spreading wings. The female is wingless and legless, essentially a larva that never grows up. A moth that never flies. The males are different. They emerge as small, grey, furry moths with delicate wings, living only long enough to find a female's bag, mate and die. They have no mouthparts and do not eat. Their entire existence is a frantic, few-hour search for love. A life that is almost too short to measure. Once the deed is done, the cycle continues as the tiny larvae hatch inside the bag, spin their own silk, and begin collecting debris to build their own miniature castles. To the gardener, they are often invisible until the damage is done. A shrub might look healthy from a distance, but up close, dozens of lichen-covered bags are clinging to the stems, the inhabitants munching away at the leaves. They are masters of camouflage, turning the very environment against the observer. They are a testament to the strategy of defence over offence, proving that sometimes the best way to survive is to never leave home. The branch looks clean. The bags are hidden, lichen-covered, invisible. Inside, the female waits, wingless and legless, surrounded by her eggs. She has never seen the sky. She never will. She does not mind.