I have my Dubia colony in my garage during the hot So Cal summer. Yesterday it finally reached 100 degrees in their tub, which I've heard can be deadly if you keep it at that temp for an extended amount of time. But it got me thinking, at what temperature will they perish, in terms of short term exposure goes?
100 is a little high but I don't think it would hurt them in short bursts. They are tropical bugs so they're used to pretty warm temps in the 80s and 90s. 100+ for a sustained period won't likely do them much good but I'm not sure exactly what their temperature tolerance is.
Do you happen to know if they would breed at 77 degrees and 40-45% humidity? That's the highest I can get it inside my closet. Garage during the summer has been great at 85-100 degrees and 50-60% humidity.
77 isn't bad. Yes they will breed at that but slowly. I keep mine in my basement which is 60s most of the year. I have an under tank heater which puts about half of the tank into the 80s/90s and does the job. They're pretty tough so I think it really comes down to provide them with what you have and just wait.
To achieve those parameters in the closet, I need to run two reptile heating pads in the tub. Plastic seems to absorb the heat, so it won't get higher.
I use one pad and pile a bunch of cardboard tubes (toilet paper, paper towels) on top and they seem to figure it out. I wouldn't go too crazy modifying their environment. Give them a gradient and they should be fine.