hhw is right. It's a highly contentious issue for monitor lizards, but for many others, there is PLENTY of proof. Take bearded dragons for example - one of the top causes of death for them is Metabolic Bone Disease, which is caused by a defficiency in vitamin D - something their bodies cannot absorb from their food without, yup, you guessed it - UV LIGHTING.
As for the plant bulbs, what is their UV output? Less than 5% UVB, scrap it.
- Ken LePage