Questions from Barry on longevity,survival in cold temperatures

Hi, Barry here.

I have a couple of questions about Mason Bees.  Any help would be great.

I have been raising Mason Bees for 3 years now in Minnesota.

I had purchased them on line.

I started with about 120 to 180 bees and have doubled or tripled my
count.  I have made multiple types of Houses and Traps.

If my Bees fill every hole, reed, tube and cavity I have put out for them
I figure I might have as many as 1000 Bees to store this Fall.

My first question is how long can Mason Bees be kept dormant?  It depends on the amount of fat reserves the bee has- ie the amount of food it was fed during development during the previous spring. 

I would like to start putting some out next year in April and continue
putting out more Bees for a couple of months.

Could dormant Bees be kept in a Small fridge for over 6 months?  Yes, but it would depend on their food reserves in the form of fat reserves.

I pull the Bees houses down in November and store them.
By April it has been 6 months that they have been in my fridge.

I have an old Dorm Fridge that works really well for keeping them at a nice 35 to 38 degrees.
This lets them have the “cold snap” they need without stressing them from the great outdoor temps.

Second, I would like to know what is the coldest temp that Mason Bees could survive?
I’ve seen Minus 26 degree temps just in my backyard here in Minnesota.
I have heard that 10 degrees and colder can do them harm, any thoughts on this?  I would generally agree with your statement.  My recommendation are to keep mason bees away from minus temperatures.  A good way of doing this is by keeping them in the fridge.

When I open my house to clean and collect my Bees, should I separate any different bees like Masons and Leafcutters?  I separate them out because mason bee cocoons can be cleaned and leafcutter bee cocoons cannot be cleaned.

Should I put them out at different times during the year?   Since setting cocoons out at the nest makes them vulnerable to predators, I would set them out close to their natural emergence time.

Bonus Question, how far will Mason Bees travel away from the bee house to find Pollen?  I have read they can fly about 300 meters to 1500 feet.  Is this about right?  It depends on the density of bloom and availability of food.  In a commercial blueberry field most mason bees travel within 500 feet.  In a suburban lot, bees were observed to fly a distance of 3 lots, which is no more than about 300-400 feet.  

Thanks for your time.