About 3 months ago I thinned out my dubia colonies because I had close to 600 adult females in each one. (I have 6 total) I sold close to 2000 adults and got 4 bins back down to 300 to 400 adult females each and separated all the nymphs into 2 other bins. I put an under tank heater on one bin and left the others at 85º room temps in my fairly warm dragon room.
Three months later, the bin with heat is full of nymphs from baby to 1/2" and I feed them 1/4 cup of food and water crystals twice a day. The other bins have lots of babies, but only about 30% of the heated bin, and none are over 1/4" long.
So basically, heat makes a huge difference in their metabolism!
I also did an experiment like this with a whole colony.
The temp stayed at a constant 72 degrees during the day, and at night would get into the 65's near the bottom of the bin (where the heat pad is).
These conditions were kept like this for ~3-4 months.
Results:
Very few births.
A very slightly higher number of dead (and I mean VERY slight)
Growth rates seemed to stay the same as with heat.
Hunger for food seemed to stay the same.
Basically what happened was my colony turned into only adults.