Not a silly question at all.
My beardie is 13" and the moths, well, how do I put this? Um, the males are about 1/2" long and 1/4" wide and the females are about 5/8" long and 3/8" wide.
It is important to point out what insect you are feeding your beardie makes a big difference in the size that is recommended. For example, a cricked that is bigger than the space between the beardies eyes is not recommended because the cricket has a hard exoskeleton that is undigestible. You do not need to go by the same rule for silkworms because they have no exeskeleton that would cause impaction. The moths they produce do not have a hard exoskeleton either so, in my opinion, the crix size rule of thumb does not apply with them either.
However, to be on the safe side I don't feed the female moths to my beardie until I am sure she has layed her eggs and even then I only feed it to my big beardie who is at 18". On top of that I only feed a couple of moths at a time whether female, male or going to the bigger or smaller dragon. I just don't think there's enough info on the moths yet to fill my dragons up with them.
I haven't had moths for awhile now but when I had a bunch the majority of them died before they got fed out.
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Rob Talkington