There are plenty of well established breeders that feed just mealworms. Crickets are not a required food item it is all personal preferance. As long as you are making sure the worms - crickets - roachs ... whatever are gutloaded and the gecko is getting the best nutrution you can give them then do it. I mix it up from time to time with crickets but mealworms are the staple diet. I also feel like the geckos chasing the crickets give them alittle needed activity that they dont get from bobbing for worms in a dish. This is just how I prefer to feed mine you can do what you feel is right for your animals.