Hi, As no-one else chimed in I'm not sure anyone is interested but as an update I investigated further the reasons why the F1 etc produce silk when the adults don't: Aparently the commercial producers of wax worms freeze the worms for a short time and this destroys the spinneretts! I'm not sure anymore how long or at what stage they do this as once I had discovered the reason I promptly forgot and was only reminded when I spotted the message I had previously left. If anyone is interested I am sure I could find the site again which details how to replicate this effect at home. At the moment as I am producing them for moths I find the silk production more interesting than a nusence. If I were to feed my wax worm to my geko's then I might prefer the silk production to be reduced.