its mainly the extremely high moisture that they require, I'd say like 80-99%, if you keep the nest hydrated well enough you could have a dry outworld to avoid mites and all the annoying stuff, without the moisture they will die, I had a colony die within a day due to dehydration. I know there are some subspecies of diversa from South East Asia that can do well In dry conditions, but they're not as common. you can use plaster nests, they often provide nice moisture, and you could tell if the nest is drying up from the color of the plaster. soil is also a good option, if you're thinking of using soil as/for their nest, you should boil the dirt/soil before using if they're collected from your yard, since they could contain mites and mold. (they both kill diversa extremely fast)