So i read that hornworms woll have a hard time pupating if they didnt have a diet of tomato etc.? I have fed mine carrots and its trying to burrow my dragon wont eat them and im just letting them grow, anyway i can get him to pupate correctly?
When they are ready to pupate they do start to change color, getting muddier/paler colored if I remember right. They will stop eating and start to wander about to look for a place to safely pupate so if they are turning down food this is a good sign they are on the way to pupation. They will even start to sort of shrink up and change texture if they can't find a place to burrow into soon enough. This shows the body changes pretty well.
They eat nectar. I think you might have luck setting them up with a hummingbird feeder? I've not kept them, pepper likes to eat them so I've never had to feed them anything.