I just received a large order (1300) 7/8" Dubia from a well known breeder...
The overwhelming majority of the nymphs came in alive and healthy. I noticed, mixed with the frass, lots of molted shells and some type of "worm" The worms are tiny and can only be seen when viewed up close.... What can they be? Are they harmful?
Without seeing a pic, I would say its most likely a "cleaner bug". I have no idea what kind of bug it is exactly, but some roach breeders use them to help keep the mold to a minimum in the roach enclosure - the cleaner bugs eat it. They are harmless to you, the dragons and the roaches if that IS in fact what you are seeing.
Not a worm, larvae. Almost certainly without a doubt a species of dermestid beetle. You should see beetles at some point as well. They're a decomposer and will clean your colony by eating freshly dead roach carcasses. It reduces need for cleaning and restricts die off in the colony, because deaths in a colony almost invariably cause more deaths. Keep them in! They're good for you. The beetles are good feeders for small animals as well. I have a fat tail gecko that only likes to eat beetles.
technically they are larvae but don't forget this is the feeder section. Any "larvae" is considered a worm in the reptile hobby ex. waxWORMS,hornWORMS,silkWORMS,PheonixWORMS
I specified larvae because as cleaners they're called dermestids, which identifies the beetle family. We call those feeders in the hobby as worms because we feed them in the larval state. Those are the common names for them because of the practice of using their larval, not mature state. But I also identified it as larvae for them to know that what I am identifying will become a beetle, and that the poster will be seeing beetles as well with their dubia, so as not to surprise them again in a few weeks. I've never heard them called dermestid worms