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Purebred vs hybrid: why it matters

Updated: Mar 8

Some have noted that I offer two different types or varieties of discoid roach; Banana Bay and Redlands. Before those two there was only one, and while not currently for sale I have dubbed it the "Richmond Hill" variety.

When I started selling discoid roaches a couple years ago I made sure I bought some from the first group to be brought in.

The insects Iinitially picked up were exclusively nymphs, fair given that was all that were sent. As time passed I was a bit disappointed with the glacial pace of their growth, and read conflicting information on how long the journey to adulthood was to take: 3 OR 4 months...? That's a pretty big gap. My surinams could take 6 or 7 weeks to mature, based on conditions, but a 7 day gap is a far cry from 30+ days. Nevertheless, I was patient and waited for their final molt with great anticipation.

Finally the day arrived, and I was looking at my newly molted adult. It seemed...smaller than I thought it might be. Not substantially, maybe only 6 or 7 mm, but not quite as big as some of the pictures and descriptions I have seen and read. Another molted shortly after and I saw another issue: the wings weren't closed tight along its back. Instead the underwings were sticking out to the sides, like it couldn't fit them under its outer elytra that covered them. Ultimately, in my mind, this was of no real consequence given that this species can't fly. However they do use them to communicate with each other, displaying to rival males and potential mates, intimidating others away from food, and to express excitement. I simply chalked it up to inadequate humidity and changed conditions in the tank I kept them in. With time I found more and more with similar wings, regardless of humidity levels.

Now with adults in sufficient numbers I looked forward to seeing my first group of baby nymphs appear! I had close to 10 adults, and they were well past their final molt by weeks. I looked through the cage substrate almost daily, at first with hope and excitement, and as time dragged on with frustration and annoyance. After a fairly lengthy amount of time I finally spotted it; a tiny little nymph!!! Giddy with excitement, I carefully moved the adults out into a seperate bin while I sifted through the bedding of their cage. First one...then three...another two....

In the end there was a total of....14. Fourteen? Less than expected...a LOT less.

I reasoned that perhaps their first litter is always on the smaller side, that maybe they'd increase as time went on, however I wanted to do some serious research into exactly what was going on.

Research I did, and boy, was that an eye opener.

The discoid roach has been used as a feeder pretty much since people in the US started keeping reptiles in captivity and were also the original "lab roach" used in experiments and behavioral studies by researchers. Favored for their large size, docile temperament, ease of care, other characteristics which lent themselves to being ideal captive specimens, these roaches became popular and widely kept. With time other species of roach would be imported into the US, largely as keeping invertebrates became popular in its own right. It turns out there are at least four other species which can cross with discoid roaches to create viable offspring, and whether intentionally or accidentally, they hybridized with discoids. At first, not a big deal, there were plenty of purebred discoids still around. As time went on however, these hybridized specimens were sold, traded, and spread through the hobby, bringing them into contact with pure populations. With enough time the number of purebred discoids dwindled and various hybrid lines took their place. Eventually, it was found that, to one degree or another, hybrid discoids represented almost all the specimens found in the hobby by the late 1900s.

The results from hybridizing between species is NOT the same as within a species. The notion of "hybrid vigor," when two individuals in a meta-population with differing genes mate conferring genetic diversity to their offspring it can avoid passing down genetic "mistakes" that can be observed in populations with heavy amounts of inbreeding or line-breeding. In contrast, with mating between species, you're playing a genetic lottery.

Sometimes, the hybrids are stronger than either parent, such as with the broad-leaved and narrow-leaved bulrush whose hybrid offspring outcompete both. In other cases the offspring is better than their parent in some aspects, ligers and mules being bigger or stronger, respectively, but both crosses are sterile and unable to breed. Finally, in a fair number of cases the hybrid offspring is such as genetic mess they are not only infertile, but much weaker than either parent (ie Camel×Llama, leopard×lion, and many others). The offspring of such crosses have their fertility greatly reduced, if they can have offspring at all, and come with a multitude of health problems.

In the case of discoids the hybrids which came to dominate the scene appear to have gotten the shorter end of the stick; they grow slower and smaller, are less fertile, and often have slightly deformed wings (that last aspect I have been told is a "sign they are hybrids"). While it wasn't the fault of the guy who initially imported then, given that is almost exclusively what is available in the US hobby these days, it was a poor introduction to many novice keepers and anticlimactic for who had high hopes and expectations resting on these new feeders.

Some time passed and an individual out on the west coast claimed he had purebred discoids. After chatting with him I found out that he had imported two purebred varieties from a roach enthusiast down in the US who runs the company Roach Crossing. These two varieties were established from feral populations established in southern most Florida in the early days before the flood of other species entered the states and the subsequent hybridization. The owner of the company is very passionate when it comes to his hobby and is proud to have kept these two varieties isolated from each other and more importantly from any outside hybrids. I wasted no time ordering a number of both varieties and eagerly awaited their arrival. The hundreds of nymphs which arrived were notably superior in quality, but it was with the purchase of a group of Redlands adults which really showed the contrast with my old stock.

They may have cost more but boy, the difference was obvious! The adults I received were stunning! Perfect wings and form, the maximum size for their species, and even the beautiful but subtle colouration not seen with the hybrids. I was smitten!

Upon releasing the males to join their virgin female counterparts in the new enclosure I observed the largest male immediately displaying with lifted wings to the nearest female. Over the following days I regularly came across one or two paired up and mating. There have now been a large number of babies born and they have easily outproduced the hybrids from before. The contrast between the pure and hybrids is not gigantic, the hybrids still pass for discoids, but the differences are enough for it to be notable and significant.

Speaking to my current situation: I now offer both the Redlands and Banana Bay varieties from my collection. I have paused the sale of the Richmond Hill variety for a few reasons. The first is I am hesitant to offer something which is lower quality when I have better quality specimens available. The second being that while I have babies from the RH hybrids, they are taking so long to mature they aren't yet ready for sale anyways.

I am still considering whether it is even a good idea to offer the old hybrid variety, which would be cheaper, alongside the more expensive new purebred varieties. There would be the temptation for some unethical individuals to potentially cross the old and new lines, and to then sell them as purebred. While I realize there is nothing to stop them from doing so at this time I am hesitant to provide anyone with an easier opportunity to do so by selling hybrids alongside purebred.

At the time of this writing I do still maintain the colony of hybrids, whose fate has yet to be determined. My immediate plan is to showcase the purebreds next to the hybrids to show people the differences between them. Beyond that they are simply being used as feeders while the other pure varieties are saved for sale.

For those who made it to the end of this blog I would love to hear your thoughts; what do you feel should be the fate of the hybrids? Do you feel they should be made available for sale eventually, if ever? Any members who provide a response on this subject will be given 15 points to redeem with the rewards program (limited to two times, response must be more than a couple words).

Thanks for reading!

update 03/09/24 - as of this update we are now selling a high-quality hybrid line, "York," alongside our purebred varieties. To purchase either purebred or hybrid discoids please check out their product page by clicking this link:

1 Kommentar

Noah Patterson
Noah Patterson
24. Sept. 2023

Hey Jordan. Very interesting read! I guess my perspective is that of pragmatism in regards to my feeders. Does hybridization affect nutritional qualities of the roach? Your observations seem to suggest that there are significant differences in behaviors between purebreds and hybrids, so perhaps there are physiological differences affecting physical heatlh? When buying my feeders I generally go with the cheapest option(s) for the basics (eg crickets, superworms, mealworms), and will occasionally splurge on pricier, more robustly nutritious insects (eg hornworms, silkworms). This is so I can provide more nutrients and cater to my more fussy eaters. This means I'd consider hybrids for basic feeders and purebreds for treats, if prices are noticeably different.

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