I keep my bin as dry as possible, except some damped moss at one corner, and some water crystal at the opposite corner. I spray the moss to a point that they will dry out in about a day and respray everyday while I was catching a few for my geckos, I only give them a few water crystals every few days, they eat them like chocolate. The bin is very warm, not sure the temp, but i have my computer placed at the section below the bin, and it is hot. Just leave them alone, and you'll have more dubia than you know what to do in no time, well... not really no time, maybe a month or 2 if you have enough adults, say a few dozens?