Found this on a Dubia breeding site:
Keep your feeder roaches at a minimum temperature of 68 degrees. Dubia Roaches are Tropical Roaches and need to be kept warm. If you want them to breed, keep them warm. Day temperatures between 85 to 95 degrees are preferable. Humidity levels should be mid range. Unless you live in a very dry area of the country, there will be enough humidity at 90 degrees.
-Jay