Amy Mannering, of View Hill School, asks :-

How does a case moth make its cocoon? I thought it was made out of skin on the inside.

Simon Pollard, an entomologist at the Canterbury Museum, responded.

The common case moth is a native species and is found throughout the country. It spends the caterpillar part of its life cycle inside the insect equivalent of a cigar-shaped, silken sleeping bag. The bag or cocoon is made from silk, which the caterpillar makes inside glands next to its mouth. When it pulls the liquid silk out of its mouth, the silk forms threads that can be woven into a case. The moth also adds bits of eaves and bark into the case to make it stronger and more camouflaged. Case moths eat plants and stick their heads out of one end of the bag so they can feed, while all the caterpillar droppings fall out the other.

When the caterpillar is fat enough it seals its self inside its bag and pupates into an adult moth. The male has wings and flies around looking for female case moths. The female cannot fly and spends her adult life inside the bag where she lays her eggs The young larvae leave the mother and the bag and feed on vegetation before building their own cocoons. Imagine spending your whole life inside a sleeping bag!

The Maori called case moths pu a Rakataura which means the flute belonging to Rakataura, the goddess of music. Apparently, Rakataura made her first flute from the cocoons of the case moth, but when she lost the flute, she started to live inside the cocoons. Once inside, she stopped making good music and now, funny noises inside the forest are the only music that Rakataura can make.