Dusting will likely always be necessary. I have read much that says you cannot gutload a fruitfly. However, I cannot seem to find any tests of the insects (gut-load vs non gut-load). Repashy is doing the same as I am, I have read the reviews, but never find documented tests.
Is it insect type that meets the frogs needs in the wild? Or the natural gutloading of insects consuming natural, varied foods moments before becoming prey? Again, no documented testing. And from previous work I have done with insects, you can never forget the content of the flora inside the insect.
It is said a fruitfly evacuates its contents in 6 hours. Yet, my frogs eat LOTS of flies as soon as I put them in. I have read about various reasons why the media itself would lose nutrients before the flies even ingest it. Yet again, no one seems to have actually measured. Other than just basic fruitfly nutritional content (the bugs themselves), no one can seem to point me to an actual measurement, even the ones making the claims that it won't work.
It may need to be actually measured unless you know of such a study already done? I have come up blank so far.