As far as we all know, heliothermic reptiles -- people who frequently bask in sunlight -- desire
UVA UVB Mercury Vapor Reptile UVB Bulb so as to generate Vitamin D3 in the skin. A number of them also appear able to utilize vitamin Vitamin D3 to varying extents, but specifics are lacking and many do badly if denied UVB exposure. Captives generally do good without UVB light, given that adequate D3 is within the diet. Many if not all may even manufacture D3 in skin, therefore
reptile heat lamp might be helpful as "insurance".
Amphibians use dietary D3, and many appear to not demand UVB exposure. There's some evidence, but that low levels might be of use to Poison Frogs and other diurnal species. As field studies have revealed that plant cover doesn't block all UVB, it follows that diurnal amphibians will get some exposure. On the flip side, epidermis and eggs of several amphibians contain compounds that filter-out UVB. We have a wonderful deal to understand.
