Matt K Posted August 16, 2007 Share Posted August 16, 2007 Quote Link to comment Share on other sites More sharing options...
Gsc Posted August 16, 2007 Share Posted August 16, 2007 Great pic man. I've had a few black ones pop up in past colonies but never kept an entire group. Do they breed true or do you have to cull the non-black offspring? Once I get some more bucket cages made up I may have to bug you for a few to start a colony with... Quote Link to comment Share on other sites More sharing options...
Matt K Posted April 28, 2008 Author Share Posted April 28, 2008 These breed true. Thus far I have had less than 2 percent variations, and less than 1 percent show any 'normal' colorations. I may have some available now. Quote Link to comment Share on other sites More sharing options...
Ralph Posted April 28, 2008 Share Posted April 28, 2008 Sweet picture. Are black G. portentosa "rare". I've been hearing about them and noticed that a lot of mine are black. Quote Link to comment Share on other sites More sharing options...
EffeCi Posted April 28, 2008 Share Posted April 28, 2008 I bought 30 of them from a german breeder just one year ago... now they're more than 240... Quote Link to comment Share on other sites More sharing options...
Matt K Posted April 28, 2008 Author Share Posted April 28, 2008 Black G.portentosa are common. Black G. grandidieri are rare. I have colonies of both. Of the G.portentosa 'black morph', a substantial but variable percentage of the offspring grow to normal coloration but carry a genetic perpendancy towards being black, so you have to "weed out" the normals frequently to keep the colony black. Of the G.grandidieri blacks, very few if any of my nymphs ever exhibit normal coloration. Out of several hundred I have only ever had to pull five out. I am sure that with some variables thrown in a few more could pop up normal color, but the percentage would still be extremely low compared to the G.portenosa, therefore I believe that the G.grandidieri would be more desireable as a black hisser. Quote Link to comment Share on other sites More sharing options...
crepsis Posted April 29, 2008 Share Posted April 29, 2008 I know part of this is a bit off-topic, but are there any studies that have been done on the genetics behind different roach morphs? Is it as simple as a dominant trait or a recessive trait, or is the black determined by something more complex? Quote Link to comment Share on other sites More sharing options...
Matt K Posted April 29, 2008 Author Share Posted April 29, 2008 I know part of this is a bit off-topic, but are there any studies that have been done on the genetics behind different roach morphs? Is it as simple as a dominant trait or a recessive trait, or is the black determined by something more complex? It appears that in G. portentosa the gene is a recessive one from what I can gather. If left to thier own devices the colony would return to a majority of normal colored roahces. With the G.grandidieri it may be a dominant gene, or true black. Again, this is just based on my own observations. Quote Link to comment Share on other sites More sharing options...
BugmanPrice Posted April 29, 2008 Share Posted April 29, 2008 Has anybody tryed to do some crosses to see what ratios they are getting? It appears that in G. portentosa the gene is a recessive one from what I can gather. If left to thier own devices the colony would return to a majority of normal colored roahces. With the G.grandidieri it may be a dominant gene, or true black. Again, this is just based on my own observations. Quote Link to comment Share on other sites More sharing options...
Matt K Posted April 29, 2008 Author Share Posted April 29, 2008 Has anybody tryed to do some crosses to see what ratios they are getting? Crossing what to what? You mean as in to cross or hybridize the black and white grandidieri with black grandidieri (almost no similitudes exist in the hobby of grandidieri to 'normal' portentosa) or do you mean to cross a grandidieri with a G.portentosa? Orin (unintentionally) made such a hybrid and they may have been destroyed. You would have to contact him and see if he kept them alive or not. Quote Link to comment Share on other sites More sharing options...
BugmanPrice Posted April 30, 2008 Share Posted April 30, 2008 I mean crossing a normal roach with one of the black phenotypes (of the same species) to see if you get a 1:2:1 ratio. Do you think it's just one gene? I didn't think that portentosa would hybridize with grandidieri; I assumed the male genitalia would be too different. Do you know if the offspring were viable? Just curious. Crossing what to what? You mean as in to cross or hybridize the black and white grandidieri with black grandidieri (almost no similitudes exist in the hobby of grandidieri to 'normal' portentosa) or do you mean to cross a grandidieri with a G.portentosa? Orin (unintentionally) made such a hybrid and they may have been destroyed. You would have to contact him and see if he kept them alive or not. Quote Link to comment Share on other sites More sharing options...
BugmanPrice Posted April 30, 2008 Share Posted April 30, 2008 and Matt... what's that on your personal picture? Pretty cool. Quote Link to comment Share on other sites More sharing options...
Severus Posted April 30, 2008 Share Posted April 30, 2008 Cool! Here is a younger one that came in my last group of grandidieri from David Grimm. I really didn't think much of it until I saw your pictures. http://i63.photobucket.com/albums/h146/Mok...imals/Black.jpg Quote Link to comment Share on other sites More sharing options...
Matt K Posted April 30, 2008 Author Share Posted April 30, 2008 Bugman- that roach used as my personal picture is a Gyna sp. that I saw in east Africa climbing tall grass. Saw alot of cool bugs that trip (west side of Tanzania). Severus- I would isolate that dark colored roach and grow it to maturity away from the others. This way you know it does not reproduce outside of controlled conditions. What you have there is a throwback or genetic irregularity that may be worth investigating. The blacks that I have are normally black, not recessive black. Black and white grandidieri are normally blacka and white by nature, not by selection, so any oddities that you get are curious- I may even want to buy/trade for it sometime. Quote Link to comment Share on other sites More sharing options...
Severus Posted May 1, 2008 Share Posted May 1, 2008 When the temps get a little more stable, we can work something out. Quote Link to comment Share on other sites More sharing options...
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