So I bought these a while back, I could definitely tell what I think were the giant females. They were noticeably larger. I'm not sure if the others are males, or regular banana roaches. Im also unsure if they can hybridize if they happen to be mixed together... I'd really like to get a steady colony of giants going, but I haven't seen any of the really large(relatively speaking) ones in a long time. Mainly just nymphs. I recently put them in a new bin without isopods stressing them out so hopefully that helps with the breeding.