I only get concerned with the temp when it climbs much above 70f......beetles hatch at 80+ I think. My humi and coolers pretty much stay in the low 60f and even the mid 50's during the winter........during the summer it will raise to the mid 70's and it is time to move them to a cooler place.

I don't know for sure regarding the tube, but I would guess airflow around it would be important, but maybe less so in the smaller environment of the jar. I'm sure someone else will have more info on that.