I have had many species of treefrogs, eat silkworms! My whites seem to love them, along with a couple other treefrog species I have, and my bumble bee toads etc. I don't think you would have a problem getting the majority of frog species to eat silkworms. I think it depends completely on the frog itself. As far as beginner frogs go, I would say whites treefrogs, because they are very tolerant of different conditions, eat well, and are very nice to look at, mine are also fairly active which is fun to watch. The require a temp of about 80-85, and like to be humid at around 60-70% but can also do well at a lower humidity, I however keep mine fairly humid and have had no problems. What I wouldn't recommend for beginners are frogs like pacman, pixies, or other species of bullfrogs, only because these frogs have a serious appatite and have been know to bite. They will eat anything they can get in their mouths, and are not the most active frogs to watch. I do however keep pixies and pacmans and they make very cool pets! It all depends on what you are looking for in a frog species. Also bullfrogs from north america are super active and to be fair to the animal require a lot of space!!! And in my experience the most "aggressive" frog I have seen is a bullfrog, but I love em anyway! Just my opinion!
Kristen 