I've found mealworms (Tenibrio molitor or Yellow Mealworm) can be raised in black plastic containers outdoors in a temperate climate provide the containers are in a sunny position causing them to heat up during the day. A simple, basically free, form of passive solar heating.
Mealworms of course require heat (and darkness) to survive and flourish but they are also surprisingly tolerant of temporary cold. They survived all winter outside in the containers here, where the night temperature typically drops to between 5 C and -3 C (zone 9, Wellington, New Zealand).
By contrast when I tried raising them inside the house, including above the water heater, this quickly failed, presumably because it was not nearly hot enough.
I had to secure the containers with wire mesh to stop them blowing away in the wind. I also taped screening around the lid to prevent the adult beetle from climbing out, I'm not sure this is necessary they don't seem to have thought of that so far.
Another problem was figuring out if the containers were safe for raising insects in, unsurprisingly there is not much info on plastics suitable for insects. Some manufacturers market containers as "food grade", suitable for keeping food in, which I took to be ok, but finding one that says that and is black may be difficult. I resorted to buying a blue "fish bin" (for keeping fish in, presumably safe) and painting it black. It might even be possible to make a container out of wood and paint it black if you don't like plastic.
I just feed them grass and weeds from the garden I know to be edible for humans, reportedly they will eat anything that is rotting.
I have never raised mealworms with the usual artificial heat so can't compare productivity of outdoor containers with this. So far, I've only had them a year, they appear to go through one life-cycle a year.
My interest in mealworms is as part of my own diet and part of an effort to produce most of my own food on a small section. Mealworms appear to contain all the essential nutrients fruit and vegetables lack, so could possibly be a wise addition to a small self-sufficient homestead that can't fit larger animals.
I tried eating a few the other day, after fasting them for 24 hours. I fried them in olive oil, they were crisp and melted in the mouth, not much to them. I suppose they were a little like the skin of Kentucky Fried Chicken, not bad, but bitter as well, something I fed them perhaps, or the oil? Will have to do more work in this area.