He looks like hes in great hands :D. Are you feeding him veggies as well? also heres a tip for ants I found a ease way to stop them that's completely safe for the bearded dragon! If you take scrapbooking double sided sticky tape and put it around his cage below any doors. One layer all the way...
I put double sided tape on the outside of my tank to keep ants out not sure why it works but it dose for me. I like it because its completely safe and is cheap the tapes on the outside so the dragon cant get to it!
I feed my dragon the pellets as a staple of his diet and hes doing wonderful hes growing like a weed :D but as for ideas maybe cut them up smaller or try a lazes pointer my dragon chases it like a bug so maybe pointing it at the food would help or if your really brave try blending some bugs...