I've read tomato frogs are crepuscular, so would receive some exposure to UVB in the wild and probably have adapted to use it but in short periods of time. Relying on D3 from the diet is a hit or a miss depending on the species. When relying on D3 from supplements then there's a lot of guesswork in how much to actually provide and I see lots of variations on how often to supplement from care sheets on all animals. Supplements would still need to be used when using UVB lights but you could use a low level D3 one to be safe, like repashy's calcium plus LoD so to provide some D3. With the repashy calcium plus its designed to be used at every feed so you don't have to worry about under supplementing. I provide my american green tree frogs with UVB, my fire bellied toads had UVB, I'll be getting darts soon and they'll have UVB and in fact the only animal I don't give any to is the horned frog, as it would have such a varied diet in the wild it would probably get D3 from whole prey items such as fish, small mammals and other frogs. Most frogs and toads have been said to have no UVB requirement but now as more information and thought it put into it that's no longer the case.

http://www.amphibianark.org/pdf/Husb...tamin%20D3.pdf
http://www.arcadia-reptile.com/wp-co...omato-frog.jpg