Anything from a gallon container to a five gallon tub works for a starter culture (and the latter should work nicely as a permanent colony setup). A few inches of substrate such as coconut fiber, potting soil, etc. should be provided, this serves as the main living area for the burrowing nymphs and adults. Above-ground hides will only consistently be utilized by adults, mostly males, and aren't really necessary, but they may appreciate some branches and vertically slanted bark hides to climb on. Substrate can also be topped with leaf litter, which the nymphs will nibble on.
Some people report a chunkier substrate is key for breeding the more finicky species, but I've not really found substrate particle size to be an important factor in breeding them personally.
Some of the common species will breed fine if the entire enclosure is kept humid, but most appreciate a humidity gradient, 50/50 seems to be the best bet, vertical or horizontal gradients both work fine. Moderate to high ventilation is recommended. Adults of all species can climb and fly well, so a tight fitting lid is a must.
Diet:
The staple roach diet of dog/cat/fish food, fruits and veggies works great, with adults especially loving fresh fruits like apples and bananas. Nymphs will also nibble on leaf litter if it's provided, but it's not a necessity. Some of the larger species are very quick to cannibalize if they run out of food, so keep this in mind.
Temperature:
Temps in the 80-90F° range work best for breeding, though some of the more common species will breed at slightly lower temps (75F°).
Breeding/Life Cycle:
Adults live 4-5 months on average, give or take a month or two depending on species and sex (females tend to live longer than the males). Female Gyna are live bearers, with internal oothecae potentially containing over 100 eggs depending on the individual and species. They don't usually give birth to all the nymphs at once, more typically having several smaller litters from the one ootheca over a few months. I don't think they produce more than one ooth in their lifetime, so making sure females are happy and don't ever abort their ooths is key.
All life stages are burrowers, nymphs especially, and the nymphs typically take 4-6 months to mature, depending on the species. Males usually mature before females do, which can be a bit annoying for breeding some species, when combined with the shorter lifespan of the males, but it's usually not too bad a disparity in growth.
This genus is usually pretty hardy, but excessive numbers of mites, large filth buildups, and lapses in feeding can potentially cause colonies to crash, so those are all things to watch out for.
Other than that, there's not much to this genus, they're pretty simple to set up.
Species notes:
Gyna bisannulata:
Known as the "Patchwork Cockroach", this is one of the species that can be a bit finicky for some keepers. Females don't love being bothered by nymphs or other adults when gestating their oothecae, and excessive stress in the form of crowding can lead to females aborting their oothecae. When kept perfectly though, they can be very prolific, just make sure they don't run out of food, as they will cannibalize in a flash if they run out of food. Prefers a 50/50 humidity gradient.
Gyna caffrorum:
Known as the "Chrome Porcelain Cockroach" or more simply "Chrome Cockroach", this is perhaps the easiest and most prolific species in the genus, not picky at all about humidity or crowding, and can be potentially be used as a feeder.
Gyna capucina:
AKA the "Pink Cockroach". This is another species that can be finicky, but more forgiving in my experience than bisannulata. Females don't love being bothered by nymphs or other adults for that matter when gestating their oothecae, and excessive stress in the form of crowding can lead to females aborting their oothecae. But when given space and lots of food (they eat a LOT for Gyna, and can be quick to cannibalize), they can be very prolific. Prefers a 50/50 humidity gradient.
Gyna centurio:
Known in the hobby as the "Centurio Cockroach", a very easy and forgiving species to breed, could be used as a feeder in some cases. Not picky about humidity or crowding, and adults sport sexually dimorphic coloration.
Gyna gloriosa:
This species entered culture briefly at least twice overseas, but has never been bred successfully. Their nymphs are only known from the refuse mounds of driver ant nests, and so perhaps the adults may require a similar setup to the inside of said mounds in order to induce breeding... Whether it's the very fine, duffy substrate mixed with loads of rejected bits and parts of dead invertebrates, or pheromones from the ants themselves that gets this species to breed, or whether the people who kept them just had bad luck (like how some people just can't breed G.bisannulata or G.capucina to save their lives), who knows? One thing is for sure though, these are some of the prettiest Gyna out there, period.
Gyna lurida:
The "Porcelain Cockroach". Of all the Gyna spp. in culture, this one has probably been cultured the longest, and is certainly the biggest hobby staple among them all. Not very picky about humidity or crowding whatsoever, one of the simplest pet roaches to keep IMO. There is a yellow morph of this species established in the hobby.
Gyna pomposa:
Another beautiful species that briefly entered culture overseas, but sadly never took off. Presumably also a myrmecophile, so the difficulties that may be present with G.gloriosa could also apply to these.
Gyna cf. sculpurata:
This species, known as the "Rosy Pink Cokroach", is the newest addition to culture out of this genus, and one of the largest as well. They seem to have similar issues to bisannulata and capucina, but are more forgiving than either and seemingly even more prolific. Not that picky about humidity, but a good old 50/50 humidity gradient is a safe bet.
