Differentiation between hisser species:

[Matt K]

Orins quote- "Wow Matt, you've got a lot of handsome cockroaches. I've seen pictures of hisser colonies with white 'shoulders' in the past though I thought it included adult females but I'm guessing those photos were these. Have you noticed any anatomical details that could be used to easily separate them from the other hissers if they got mixed in?"

My reply:

Being that Gromphadorhina sp. can be slightly variable per specie, this is an excellent question. If you have more than one specie or even more than one morph of the same specie is is very helpful to become very familiar with the general morphology of each one. If any should escape or become mixed with another, you can then tell them apart and/or if you have hybrids. While some distinctions are inevident in any culture (i.e. 'giant morph'), there are still helpful signs. Please note that in nymphs, the smaller the nymph the increasingly similar they become to one another! The "white shoulders" Orin mentioned is a common shared feature in nymphs, and is retained for various lengths of growth in any hisser specie. Some, like Orin's magnificent G.grandidieri, eventually turn red. In G.oblongata they may become ivory. In G. portentosa they turn black. Each species carries it differently.

In this photo, we see a comparison of two females of approximate same size, age, and weight. One is Gromphadorhina oblongata and the other is Gromphadorhina portentosa. (Each is labeled). In this example, one can view obvious differences in the pronotum and thorax in general. Look at the size and width of each segment. The primary difference (aside from the individual color of mine in particular) would be the dimples. Each photo was taken under a bright sunlight condition in order to emphasize the topography of each exoskeleton. Note how the G.oblongata has only contortionin the pronotum, and the G.portentosa has "dimples" on the front two or three segments. This dimpling is a consistant feature regardless of individual color variation, and exoskeletal irregulatities. I have no hybrid to compare them to as I try to keep all my cultures 'pure strains'.

Basically: (including another feature evident) in my colonies is that G.portentosa tend to be more smooth, with dimples, and the G.oblongata tend to be more textured without the dimples. This roughness or smoothness can be a variable condition, though, and its the dimples that are the give away.

...And yes, in the center of the 'forehead' of the G. oblongata there is a commensural mite. Some of my hisser groups have them and others do not have so many, of which I don't know why other than maybe some produce more or less of that paraffin-like substance that may or may not be distasteful to mites. Or maybe the level of Hypoaspis miles in the tub varies....

Seems like Ihave left something out of this answer to Orin's trick question, but I am sure I will post it when I think of it.

[Chris Driggers]

That was a very interesting read. I never paid that much attention to my hissers when I still had them, but after reading this, I think I had both species in the same colony.

[Gsc]

Nice Matt- Great discussion and photos... I'm learing all sorts of new stuff. Thank you for sharing....

[Matt K]

Nice Matt- Great discussion and photos... I'm learing all sorts of new stuff. Thank you for sharing....

Thanks Graham!

I took these photos today for comaprisons' sake. I thought it was interesting:

[crittergu]

Just thought I'd throw this out but in the case of possible contamination what could be done would be to carefully inspect all adults and maybe the large nymphs but to discard the rest.

[Matt K]

Just thought I'd throw this out but in the case of possible contamination what could be done would be to carefully inspect all adults and maybe the large nymphs but to discard the rest.

True!! With some species if they get into each others colonies you are up a creek with no paddle! Inspect/keep the oldest ones and doom to the rest.....