I picked up a pear to eat last month and found someone was already busy chewing through the skin, making map like patterns.
A closer inspection showed this chappy.
so, i left the pear in a spare vivarium as you do and he kept eating and eating and eventually changed colour and size, like below.
He then disappeared deep into the Pear, that by now had seen better days.
He emerged, splitting his old skin (seen here top, in the picture below) and created a whole new structure for his metamorphosis, a wonderful pupa, with a spikey tail, that he could wiggle about in defence, or more likely defiance, as really, who would that put off?
I left Hong Kong for a while, so placed the pupa outside, and never saw the moth; but later on return i was near the pond in SaiKung, and next to some frog spawn, I found two of his relatives, happily munching on a completely different food.