They could possibly do alright, but alright is your best case. I can see red runners stressing dubia out a lot. On the other hand the dubia may eat the ooths red runners lay. Personally I keep them in different conditions, dubia on the dry side, red runners on the humid side. I haven't tried it so I can't say it won't work, but if you're looking for good numbers in your colonies, probably not the best 2 species to mix.