Dubia cockroaches are some of the best feeders you can provide for scorpions, tarantulas, reptiles and even big fish. They are far superior to crickets in my opinion. This species cannot climb glass or smooth plastic. As you can see below, I keep mine in a Steralite box which fits in a metal file cabinet drawer. I don't even keep a lid on it. I have a candle warmer with a vase of water in the back of the drawer right behind the colony which provides heat and humidity. My invert room is around 75 to 80 degrees.
Size: Adults can reach 2 inches and the nymphs are 1/4 inch and up. Multiple sizes come in handy to feed various sized animals.
Temps and Humidity: 85 to 95 degrees are best for proper breeding. Humidity in the drawer is 50% to 70%. These conditions allow for proper growth rate and molting. This species of roach is very hardy. They tolerate lower temps and short dry spells well.
Substrate: None! After a short time you will have a thin layer of frass (feces) that baby nymphs feed on initially. I don't use any substrate as the roaches will burrow into it and any substrate can lead to mold issues. You do need to provide tight vertical hides for roaches to feel safe and to ensure they breed properly. Most keepers use egg crates stacked vertically. I prefer the roach motel method you can see in the photo below. I made it out of cork sheets from the craft store. Drill holes in the corners then thread them on wooden skewers with some type of spacer. This creates about a 3/4 inch space between the sheets. Just make sure the top of the hide is 3 to 4 inches below the top of the bin. Some people put tape or Vasoline around the upper edge. No need with dubias in my experience.
Life Cycle: Dubia females can live 2 years. Males live 1 to 1.5 years. They are a live bearing species. Females will extend a white egg sac that the males fertilize. Several months later they give birth to the nymphs. Males do have wings, but can't fly. Females are shiny and bulky, with nice black, tan and orange patterns. Nymphs are more dull and have a brown pattern.
Gut Loading: I feed my colony a varied diet. What you feed your roaches ultimately get passed on to your pets. Dry dog food, fish flakes, leafy greens, carrots, halved potatoes, squash, apples, pear, banana, oranges, etc. Some people say dry cat food can cause females to abort their broods so I just use dog food which is not a problem. Citrus fruit is said to be roach Viagra and can promote breeding. Some keepers will grind up their own mixtures of dry food to a powder. This step isn't necessary. Just throw in the dry dog food nuggets and they will eat it. Roaches will hold their stomach contents for 48 hours. Gut load the night before feeding them to your inverts. I do use a shallow dish with a little ramp full of water crystals for hydration. Roaches will drown, so at a minimum put pebbles in a very shallow water dish.
Advantages: These are excellent feeders as they are fairly soft bodied, and have a better meat to shell ratio. They are about 35% protein vs. crickets which are 18% protein and mostly exoskeleton. Best of all they don't stink or make noise like crickets. Roaches do not bite so they pose no risk to you or molting pets. Crickets will kill a molting scorpion or eat part of it. Roaches are much easier to catch than crickets. These are a tropical roach as opposed to the type that have such a nasty reputation for infesting houses. If a dubia escapes, it usually can't survive, let alone breed at room temperatures. I've lost a couple over the years. I just put a wet paper towel on the ground and turn off the light...come back in an hour and it's on the paper towel. They often head to the bathroom for humidity. Flush escapees so as not to risk harming your colony...they could come in contact with cleaning chemicals or something you don't want in the colony. I have found that I enjoy keeping dubias and watching them swarm their food dish and demolish fruits and veggies offered... it's pretty entertaining.
Disadvantages: Cockroaches have an undeserved bad reputation as dirty mutant bugs that will invade your home. Simply not true. Tropical species can't do this. The single disadvantage I can think of is that they can hide in the first layer of substrate in your inverts' enclosure. Again, not a big deal as most of my inverts attack them as soon as they are introduced. Just drop the roach close to the scorpion or coax it toward the burrow entrance or hide. They will find it eventually.
Hope this helps any of you who are tired of keeping stinky, noisy, mostly dead crickets. Good luck!