I did, and I definitely understand species of Phyllobates uptaking the alkaloids through different species of beetles. But for many of the other Dendrobatid species, most of their diets (based upon gut contents) consist of ants and oribatid mites. I don't have the references on hand, but the studies I'm referring to were with O. pumilio I believe.

And I hope it doesn't seem as though I'm arguing...I'm not at all. The possible ways and sources by which they can uptake and sequester alkaloids is pretty impressive.