:2 reasons: :1. If you keep their diet varied (e.g. crickets and mealworms) they will be used to eating both. Getting a leo to switch from one to another can be HARD. They are stubborn lizards. So keep both in - for your sake and for any you give/sell to their future owners. :2. Mealworms, properly fed and dusted, have proved again and again to be just fine as the staple of a leo diet. They are cheaper and easier to breed yourself.
:OK - Just one more - it may have just been their eyes were too big for their bellies. When stool is runny I worry, but that looks like regurgitation - happens when some of mine either eat too fast one night or eat too much in an over zealous frenzy :) Good luck! -Shannon