Phosphorus questions

[Pia]

I have never quite understood the phosphorus or no phosphorus debate. I use a phosphorus free calcium supplement for my lizards (a bearded dragon and a helmeted iquana) because I was under the impression that phosphorus wasn't good, but I never knew why. Can someone explain it to me. Also, in a recent post, eyespy said that mealworms are high in phosphorus and would't be good for a sick dragon. My beardie loves giant mealworms and for awhile would only eat those and veggies but has now started accepting crickets again. Is it possible to feed too many mealworms? I see some calcium supplements contain phosphorus. Do some reptiles need it and others don't? Any info is appreciated.