I haven't been bitten by any of them. Not sure if they do or not. I have hand fed dubias to sick chameleons before, and they don't even bite when they are being squished. I have a bunch of superworm beetles, but have never been bitten by one of them, either. I have been bitten by the worms before.. not painful, didn't bother me. You know what freaks me out? Hornworms. I am glad that no one here seems to like them, because I really don't like them.
Make sure you put a cap on one end of the paper towel tube. They run out the ends when you pick up the tube, and as you know, they have no problem leaping out into space when you are walking to a cage. Luckily, they aren't fast enough to avoid my foot. I squish em when one gets loose.
Heika