Death's Heads?

[Gail]

OK, last year I ordered from a place called CVS Exotics (can't find them on the web anymore, I think they were in CA) a starter coloney of Death's Head roaches - about 50 nymphs from small to almost full grown. Kinda hard to tell what they are when they are nymphs sometimes. Well, they started molting into adults in January - and there were some that looked 100% like Death's Heads, and there were some that looked like miniature Cave Roaches or, possibly a cross between a Death's Head and a Discoid Roach as the coloring falls pretty much between the two. They have been merrily breeding up a storm and I have hundreds of little nymphs running around.
My question is this - is it possible that some of these ARE hybrids? Or maybe some other kind of roach entirely? Or are the female Deaths Heads not as black as the males or vise versa? I've never had Deaths Heads before so I just am not sure what is going on here. The company I got them from also sold Discoids so I guess there is the possibility of mix ups on their end?

Gail

 

[Wade]

I think if these roaches routinely hybridized, then most of us would probably have crosses (and this may be the case). It's so easy for roaches to end up in the wrong bin accidently, not to mention the hobbyists who do it on purpose. Usually what happens is one species eventually overwelms the other, see this thread for a discussion on two other Blabs:

http://www.arachnoboards.com/ab/showthread.php?t=23714

I think it's more likley you recieved a mix of two different species. If they were a large dealer, who didn't specialize in invertebrates, they may have had different species mixed without realizing it. Or, they may not have had enough death's heads to fill your order and tossed in a few discoids to round it out. I'd suggest splitting them up if you think this is possible. If it's possible to post pictures of each, someone might be able to give you an ID. Not me though, I'm no expert.

Wade

 

[FryLock]

It happens a lot with the Blabs i got some Blaberus craniifer nymphs this year from a show dealer and they look like Blaberus giganteus tho iv seen pic's of a dwarf cave roach Blaberus fusca which is like a B.giganteus but smaller (but no marks on the black thoax patch i believe)

 

[Gail]

Yup, some of the ones I've got look like the ones in your photo - some look like the photo of the deaths head on the allpet roaches site and some seem to be a mix of the two colors (not quite as black as a deaths head but not as light as the others...). I think they got mixed up at the dealer like you suggest Wade. I could seperate out the adults, but the nymphs look so much alike (plus they stay under the substrate most of the time) that I don't think I could figure out which was which until they mature. And if they've been interbreeding, I guess it's a mute point anyway.

Gail

 

[Wade]

To split out the Giant cave roaches from the discoids, I had to wait until they were obviously too big to be discoids! In your case, you'd have to wait until they're adult.

Wade

 

[Michael Jacobi]

Hopefully Richie will chime in here with a more expert reply, but as someone who raises three Blaberus species: craniifer, discoidalis and giganteus I can add that Death's Head nymphs (craniifer) are rounder (i.e., broader) than Discoid (discoidalis) nymphs of the same size. This is particularly noticeable in large nymphs.

The problem is that there are many sources for roaches who believe their discoids to be B. craniifer. If you have a B. craniifer colony and suspect any to be another species feed them off and only buy Death's Head roaches from people like Richie with pure colonies.

 

[ROACHMAN]

blaberus fuscus

THANKS FOR THE KIND WORDS MICHAEL !!!the roaches in that picture are blaberus fuscus which are sometimes sold as death heads good feeder roach and a good breeder not not a death head keep them the same as for all blaberus in set up and food

 

[Gail]

So, it would seem that the peeps I got my colony from mixed their deaths heads and their fuscus - but it still begs the answer as to are they inter-breeding or not? I'll have to try to get some pics of the three colors that are in there...
And Richie - thanks a bunch, again, for the colony of giganticus I got from you - they took a while to get going but I've got about 100 nymphs, maybe more, right now. I probably should have contacted you before because I was having a tough time making them "happy" which, I think, is part of the reason I only recently started getting the nymphs. I actually had several die on me before I finally, in exasperation, decided to try keeping them on a thick layer of vermiculite with large upright half rounds of cork bark and a heating pad under them. They love it - but they HATED being kept in a "hive" on a bare floor with a red heat lamp (the way I keep my hissers and lobsters).

Gail

 

[FryLock]

Thanks from me too Richie id looked online but could not be sure if they were B.fuscus or undersized B.giganteus

 

[Gail]

OK, I finally got around to getting some photos, so, hopefully someone can help me decide if I've actually got hybrids or not. I have tried to make sure that the photos show the true color as much as possible, but several of the photos which I used the flash on came out looking a bit more "orange" than they actually are - I didn't want to do any retouching though, so just imagine the orangish parts being more yellowish
First two up are what I believe are pure B. craniifer...
Next is one that shows several variations and the rest are more variations.

 

[Gail]

And one more odd ball, a new mommy too

 

[Elytra and Antenna]

Blaberus fusca and Blaberus craniifer are closely related species and some taxonomists consider them different subspeices, forms or races of the same species due to similarity of the male genitalia. They are different and have very different color patterns and each nymph grows up to look exactly like its parents and never like the other type.
I wasn't sure they would hybridize (whether you consider them species, race or subspecies it's still hybrid) but from your pictures I'm sure you have a hybrid of the two. I'd feed them to something, but at least let anyone who gets them from you know that they are a cross.

 

[Gail]

Just thought I'd give an update on this. It seems that I am starting to have the F2 generation of hybrids mature (the offspring of the first hybrids) and I am having a very large percentage of them get stuck in their molts. I am not doing any feeding or misting differently, temps are the same. The only thing different was that I had a lot of scavanger mites in the substrate. I changed them out into a clean bin and fresh substrate but the problem continues. It seems to be only when they are having their maturing molt - they nymphs are molting fine. I wonder if this is a problem that is occuring from the hybridization?

Gail