Moth
Usually reared from caterpillars rather than bought grown. The big silk moths never eat as adults at all: they emerge without working mouthparts and live about a week.
Overview
The big silk moths do not eat. A moon moth or a luna comes out of the cocoon with no working mouthparts, lives about seven to ten days on what it stored as a caterpillar, mates, lays, and that is the entire adult life. Everything the animal does at the end was paid for by leaves it ate months earlier.
So keeping moths is a rearing job rather than a pet keeping one. You buy eggs or cocoons, feed caterpillars on the right tree, and the adult is the last week of the story. A luna spans 80 to 115 millimetres across the wings when it gets there, and its caterpillars take hickory, walnut, sweetgum, persimmon and birch.
Temperament
Adults are nocturnal and mostly still. A silk moth spends the day hanging under a leaf or a branch with its wings closed over its back, and the flying happens after dark, which is when males go looking for females by scent alone.
There is nothing to interact with and no reason to try. The wings are covered in scales that come off on contact and do not grow back, so a moth that has been handled flies worse for the rest of a very short life.
Care and grooming
Cocoons want a cool shaded spot and time. Fresh ones are left alone for at least two weeks, and light spraying stops them drying so hard the adult cannot cut its way out. Species that overwinter need real cold, so an unheated shed rather than a warm room.
Caterpillars want the opposite. Moon moth larvae do best around 25 to 35 degrees C, with fresh foodplant every day or two and a light misting. Too much water and fungus takes the whole batch, which is the usual way a rearing goes wrong.
Living and exercise
Give it height to emerge into. A moth climbs after it breaks out and hangs while its wings fill, and a cage with no clear vertical run produces adults with wings set crooked that never open properly again.
Then leave it for a day. Wings and body harden over roughly 12 to 24 hours and that is the window where handling does permanent damage. A mesh cage beats glass for all of this, because the animal needs something it can grip.
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