Therea petiveriana, the Domino Roach
Welcome the New Year of the Dragon and a new blog post.
Blog posts which should be definitely more frequent than this. I apologize for my lack of availability to share my adventures with you more frequently.
If you are not in USA or Europe, roach keeping can sometimes feel like a lonely hobby. Are too few too scattered. Luckily nowadays, we can overcome the physical separation in the digital world. Better than nothing in my opinion, but just saying that as humans, we long more for physical and face to face exchanges more than digital.
So if you wanna join a discord server with other roach keeping enthusiasts, follow this link down below, and join the roach guild.
Recently, I had the opportunity to welcome in my house, the only other roach keeper in probably a 200 or 300km radius.
He came for a short trip and I invited him to my house to see my collection. He was kind enough to bring me some “presents” and we made some cool exchanges. It was a very well spent afternoon! In the end, I just wished these roach encounters would be more frequent. But lets move on to the most important part :D Roaches!
He brought me what he identified to be the real original domino roach. Therea petiveriana!!!
Therea petiveriana adult female
Colony of Therea petiveriana
“PFFFFFFFFFF BS”, you are thinking… “I already have petiveriana!”
Well think again :)
Therea petiveriana adult female
As reported in 2009 in Jorg Bernhardt website (www.schaben-spinnen.de), a well known German roach seller, there was a new species of Therea identified by Ingo Fritzsche which images I will place down below.
This species is identified as being Therea bernhardti, named after Jorg Bernhardt.
The paper starts off by saying that “Therea bernhardti n. sp. was wrongly determined and distributed by several breeders as Therea petiveriana.”
Looking at the description and the photos of Therea bernhardti, it becomes apparent that if not all of us, 99% of us would be keeping T.bernhardti instead of T.petiveriana. To many these aren’t new news. But I think they become more relevant now.
Therea bernhardti
Wikipedia also makes reference to this occurrence.
Therea petiveriana [As Pets] - “The conspicuously marked Therea cockroaches are popular as pets and easy to keep. The most commonly kept species has often been identified as T. petiveriana, but in 2009 it was instead suggested that the captive population actually belongs to a separate species, T. bernhardti, that differs primarily in the hindwings (which usually are hidden behind the tegmina), but also in small details of the tegmina pattern.[17]”
So, first let me show you, the revised description of Therea petiveriana, the specimens photos, then what I received, and finally I will show you the easiest way to differentiate and identify them each of the species.
From Cockroach Species File, under Therea petiveriana we can find the following older specimen photos:
Now lets move to the comparisons and how to distinguish both of them.
Therea bernhardti adult female (left); Therea petiveriana adult female (right)
As you can see, the elytra markings are very distinct. On bernhardti, the markings are less rounded but more elongated, while in petiveriana, the markings are rounder, just like a white version of Therea regularis.
On the hand, petiveriana also seems comparatively smaller, but my macro photos say otherwise.
Therea bernhardti adult female (bottom); Therea petiveriana adult female (top)
But markings aren’t their most reliable distinctive characteristic, as elytra markings have been observed to have a significant size and shape variance in this species.
Therea petiveriana differs primarily in the hindwings (which usually are hidden behind the tegmina). As you can see from the photos above, the hindwings in petiveriana are much bigger, wider, longer and have a yellowish/orange coloration, while bernhardti hindwings are short, stubby and generally black, with the exception of their root.
We can observe some differences on the markings of the tegmina as well, especially the part that slides under the top wing.
On petiveriana, you have a larger white marking as well as an strong orange marking. On bernhardti, such markings do not occur, only a replication of the top white marking, without size increase.
If you scroll up, and compare these photos to the specimens from Cockroach Species File, you will notice that they are exactly the same markings and patterns.
So I hope this is enough information and proof to make it clear to everyone on how to tell them apart.
My friend was kind enough to gift me several adult fermales, 20 odd something oothecas, and a starter colony of around 30+ baby nymphs.
Therea petiveriana oothecas
Therea petiveriana young nymphs
In the meantime, between getting them and writing this post, some females already lay more oothecas, and one ootheca hatched out! Aren’t they just precious as the tiniest younglings?!
Therea petiveriana younglings
Now the mission is to share them with others and the world, making sure that we keep a proper record and avoid mixing both species up in the future.
Oh forgot to mention, unfortunately, this stock does not have any locality information, which is a shame. But maybe in the future, a fresh stock with locality may show up.
Until then, let’s enjoy what we have!
Thank you for taking the time to read, hope you have enjoyed it.
Cheers!