some xanths will eat as aggressively as any cham out there, but occasionally they can be shy or picky eaters. if they are used to free ranged feeders, then they may be less receptive to cup feeding as as long as there are other alternatives available. no healthy xanth with a normal appetite is going to starve themselves because they would rather have free range feeders. things you can do; dont use clear cups. use a cup that holds feeders well, i prefer the yoplait yogurt cups that are skinnier at the top than the bottom, they hold feeders better than straight walled cups. its important there is something in there when they do check it out, otherwise, he will just learn to ignore it. to start, use smaller feeders than normal, a small cup can make feeders look bigger than they are used to. use feeders that move, if you put dubia in a small cup they only move for a couple of minutes, after that, they may sit motionless for hrs, so even if dubia are his favorite feeder they may not be the best for initiating cup feeding, so at least have a crick or something that moves in with it. make sure the cup is in a well lit area that he can look down into from his basking spot. in the begining it might be good to show him there is something in the cup before you hang it. drastically reduce or even eliminate the free range feeders available to him, he may be reluctant at first but he will eventually come around.