Hornworms are supposed to be quite nutritious - low in fat, high in calcium, very digestible. Only captive-raised hornworms are appropriate as food for frogs, of course, since they normally consume poisonous plants like tomatoes. The artificial diet works well and results in hornworms that are perfectly safe. My woodhouse's toads and horned frogs generally love them. Hornworms do bite but this won't injure your frogs/toads - it just means that a few toads/frogs lose their enthusiasm for them. Both of my male Woodhouse's toads are lukewarm about hornworms but my females, who are more piggy, absolutely love them, and of course, the horned frogs don't care about the biting. Hornworms also seem to make looser stools than Dubia but I don't think this is a problem - it may actually be helpful for an occasionally backed-up horned frog... My large female Cranwell's eats half a dozen (or more) of the full grown larvae at a sitting, but it beats tong feeding her 18 nightcrawlers one-by-one...