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Need help with Blaberus atropos identification


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Hello, this is Mark. I recently obtained some nymphs sold to me as Blaberus atropos that are now maturing. I have seen several photos of adult B. atropos that appear almost like an integrate between B. discoidalis and B. fusca with the brownish horizontal band across the tegmina. The adults I have ecdysed about a week ago and to my surprise appear virtually identical to B. discoidalis with one exception, the males have an orange figure 8 or hourglass-like pattern on their pronotums. The females lack any pronotal markings other than the typical black spot. Neither sex exhibits the brown tegmen band. Originally I thought that the orange markings on the male would fade to black once the exoskeleton dried, but it surprisingly was retained. The markings do not have any resemblance to that of B. craniifer or any other pronotal marking I have yet seen, leading me to believe these are not the product of hybridization. Does this sound like the classic description for B. atropos or could this be a different species? The seller mentioned that the original members of his colony came from a well known breeder in Germany and is certain that they are a pure strain of B. atropos. I wish I could provide photos but my camera is currently not functioning. Unfortunately, I can't find much information verifying the identification of B. atropos let alone most lesser known members of the Blaberus complex. I would appreciate any opinions and suggestions.

Thanks, Mark

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Hi Mark

All Blaberus sp. I ever saw had the same marking on males and females. Only B. craniifer exhibits some sexual dimorphism in the color depth (males are often lighter) but not in the pattern.

Do you know who exactly the seller in Germany is? One of the best known is Jörg from Schaben-Spinnen.de where you find many photos on the HP.

Did the nymphs look equal or did you have rough brown and shiny black ones accidentally?

If you happen to have a scanner: Get some colored pens and paper :D !

Grüessli

Andreas

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All of the nymphs have the "rough" brown appearance typical of most Blaberus. There are no obvious color variations or abnormalities in either nymphs or adults however one of the pronotal markings of one adult male is darker than the others which I know is not uncommon. The name of the breeder in Germany was not disclosed to me.

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Do I understand you right: It is just the shape/form of the 'death head' on the pronotum of the males which looks like an hourglass instead?

I have one single B. atropos/discoidalis with a nearly plain black pronotum: I guess it's just 'imperfect nature'; could be the same in your case ;) .

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The figure 8 marking bears no resemblance to the skull shape on B. craniifer. Also, the upper corners on both sides of the pronotal spot are pointed and stick out a little. I'm buying a new camera tonight. Hopefully I can get some pics to show.

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On a side note, if anybody in the US is fairly sure they have B. atropos, I know a scientist that would really like to confirm this. I don't want to get his hopes up with a "maybe" though. He is pretty sure they are no longer in culture in the US.

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Hi Mark

The thing with the "well known breeder from Germany" lets me assume that it is most likely Jörg (he keeps most species available in Europe and is the best known breeder) and then it could be Blaberus spec. 'Venezuela' (but that is a pretty rare one here around and it is only traded, not sold) where the males have a different marking than the females.... (HIS PICTURE)

It may/should be really helpful if you could figure out from whom the species is! There are only a few "well known breeders from Germany" (one is a cockroach scientist -> User Lucihormetica, but I didn't heard anything of him for months), they know each other and they are reliable (most of their species are validated by roach experts and/or the 'Blattodea Culture Group' otherwise they are sold as Genus spec. 'Origin'). Even if it isn't validated correctly it is often possible to track the roach back to its origin.

Oh, not to forget: As you are from the States and the seller is from Germany the roaches had to be imported (legally & officially) and should be trackable.

Otherwise: Dissect the male genitalia (well... a specialist should do that...) and you know it (maybe)!

Grüessli

Andreas

@Peter: And what species are they instead (if they aren't kept under the synonym for B. craniifer)?

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Thanks for all of your replies. The photo sent of the Blaberus spec (Venezuela) looks very similar if not identical. I know that Blaberus affinis is primarily found in that region. I will do some research on these guys.

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@Peter: And what species are they instead (if they aren't kept under the synonym for B. craniifer)?

A couple years ago the roaches being sold in the US by a particular vendor turned out to be B. fusca, rather than B. atropos. There is much confusion in the hobby amongst discoidalis, craniifer and fusca (and atropos).

A scientist contact tells me that the genitalia of B. atropos are unimistakable, and that they were documented in culture in the Natick lab in 1969 and studied by Roth. Interestingly, many of the species in the US hobby can be traced back to this lab.

If anybody in the US would like to have their B. atropos confirmed, I can arrange this, but I would need stock of them and especially a couple adult males.

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Thanks for all of your replies. The photo sent of the Blaberus spec (Venezuela) looks very similar if not identical. I know that Blaberus affinis is primarily found in that region. I will do some research on these guys.

Would be even MORE interesting if photos of the different genitalia per species could be posted on this forum for comparison, and the hobbiest could compare thier own personal Blaberus colony to the correct formation online....

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Would be even MORE interesting if photos of the different genitalia per species could be posted on this forum for comparison, and the hobbiest could compare thier own personal Blaberus colony to the correct formation online....[/quot

Sounds like a great idea.

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Well, without a sample of the stock, the improbable will certainly not happen. With some stock, it couuuuld...maybe.

Oh geez...how much is doubleds selling them for anyway? I tried to find them on their website, but the closest I could find was B. Atrapos. It looks like a Blaberus and the price looks good, but...

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