I'm not really clear on what you mean by taming? Is the dragon unusually aggressive when you hold it or are you putting it down on the floor in an open room? Bearded dragons have naturally calm dispositions and unless are being abused (such as a rescue dragon), shouldn't need taming.

Throw a bag of cereal and a sliced orange in the dubia colony. This will provide a sugary boost to jump start them. Give them a more nutritious staple such as chick feed and carrots/ sweet potatoes and you'll be fine.