It would be hard to culture enough springtails to feed larger frogs, even though leucs aren't as large as some others. I culture lots of springtails, I have about 20 76oz. colonies of various types, and it would probally take one colony to feed my 2.2 group of leucs per feeding, and that is without leaving enough to keep the culture going. You are also unable to supplement. IMO fruitflies are easy to culture, and if you only have a few leucs it will take only a few minutes a week to make cultures.