Flies, ants, moths,bugs,grasshoppers, mealworm larvae etc anything alive and small enough to fit in their mouths easilly. You'd save yourself a lot of insect catching if you start a roach colony, the baby roaches are perfect for juvie dragons. Also buy yourself a calcium supplement, the one with vitamin d3 added and dust every 2nd meal. I was slow to start a roach colony and my spinipes grew slowly at first because some days it was just impossible to find insects. Once i got organised with a roach colony they started growing rapidly.