Wild black soldier fly distribution and how to attract them

Hi all, I am interested in finding out the distribution of black soldier flies (Hermetia illucens). The mapping information online isn't very complete. For example, it shows BSFs are found in US and Canada in one source, in another one, based on reported sightings from individual states, there aren't sighting in some upper western states like MT, ND, UT, SD, WY etc. I guess it's only found in warmer part of Canada too. Could someone in these areas chime in with your observations?

There are online live bugs or eggs for sale.  Yet if anyone is interested in raising the BSF, it's easy to attract them naturally. If you don't mind fruit flies, house flies or other critters, just leave out some food scraps and they will come eventually. For a setup that is more BSF specific and racoon/ possum/ cat proof, I use the following:

Trash can with heaven weight inside so racoon can't tip it over
Some compost/ grass for moisture
Old bread soaked in oil/bacon grease in the middle
Some cardboards on top
Mesh/screen cover but allow fly access
Leave in the shade for a couple weeks

I usually get lots of  small bsfl quickly this way and transfer them to a shallow container for easier access.

I read about other people using fermented corn effectively too. Do you have tips for attracting BSF to share?

I don't think we have any naturally here in Maine. I have had many a trash can get out of hand for even a couple weeks (partly my fault, and partly poor trash pickup schedules). I never saw any Black Soldier Flies. Regular house flies by the hundreds. Maybe it is too cold? I'd love to get something setup for chicken feed, but I don't want to have to bring them inside in the winter.

Adult BSF are so inconspicuous I hardly see any. Before they came to lay eggs in my compost pile I had no idea they were around. They like to pupate in the ground so the soil temperature in winter time could be the limiting factor for their range. I usually pile mulches on top of the site to have more overwintering successfully. Last year I wanted some for waste processing in winter but the last generation of pupae wouldn't come out after I brought them indoor for months. As if the larvae could sense the dropping environmental temperature and set their internal clock.