Neither are all that nutritious; are you wondering if they can be fed at all or are you looking for a staple feeder insect?

Stick with crickets, soldier grubs (phoenix worms/calci-worms), roaches, locusts, and silkworms as your staple feeder insects. Waxworms are very fatty and should only be fed on occasion as treats. Mealworms have a very hard, chitanous shell that can be problematic to some species as the previous poster mentioned, and they are also quite fatty and high in phosphorus. I'm not sure how well RELF's handle them, but I wouldn't feed them too regularly regardless = )