*UPDATE*
I'm on my 2nd generation of mealworms, that have been raised on mostly pure styrofoam, I say "mostly" because I would give small portions of other food every month or so, mainly for the meal beetles that started emerging. I did find that meal beetles will eat some styrofoam, but they don't survive well on it alone and I don't believe that they break it down or compost it, like the mealworms do.
This next time around, I will remove pupa and meal beetles into another container. I plan to feed the meal beetles normal fare (fish food, fruits, and I will attempt at seeing if they will compost leftovers from foods that I eat) while feeding the mealworms only on styrofoam.
I added about 100 more mealworms to the group (yesterday) to try and get 2 generations going at the same time.
Last of all, these links were sent to me, and I will now share them with you. They are about SuperWorms composting styrofoam! https://www.the-scientist.com/news-opinion/beetle-larvae-can-survive-on-polystyrene-alone-67251 https://www.sciencedirect.com/science/article/abs/pii/S0048969719352258
If you are using mealworms or superworms to compost styrofoam, post up your experience!