I collected more acorn caps this weekend and still need to sterilize them. Photography is not my strong suit, so I took some additional photos below to further illustrate their use:
The photo of the bag containing a portion that I attached above is, well, let's just say inadequate. Here is an approximate portion of what you will receive with a Sharpie pen for scale.
Portion of Acorn Caps.jpg
I don't just pluck off individual acorn caps. I try to get them in clusters so that they are more 3-D and won't just lie flat within the substrate. Here are typical examples.
Close-up of Acorn Caps.jpg
You can fill the caps with a variety of microfauna food. Just to illustrate, here is one filled with banana (it was the closest thing available). For springs, you could fill them with pieces of mushroom and for isos, pieces of squash or other vegetable fragments. These will attract the microfauna, creating miniature feeding stations for froglets.
Acorn Cap Filled.JPG
Finally, this 1-week old variabilis froglet patiently sat in the cap while I photographed him, showing that there is ample room for froglets of obligates and thumbs to use them as hide spots. In addition to placing them in my viv leaf litter, I put them in my grow-out containers among the leaf litter.
Variabilis Froglet In Acorn Cap 2.jpg
I'm offering them for sale, not so much to make money, as to bring this idea to the attention of folks breeding species with small froglets. I realize that just about anyone in the U.S. has access to oak trees and can collect these. But, for those who don't have the time to collect, boil and bake them, I figure it's worth $5. If you do have oak trees in your area, give it a try. Just be sure to sterilize them like you would collected leaf litter.