Just curious, but do you have to add new blood, or different blood to dubia colonies to keep them strong? I mean if I start with say 100 adults, eventually everythings going to be related? Does that negatively effect the dubias?
Chris, I have 4-5 sources of different blood lined roaches, so I don't need to worry about that. Smart thinking in my book... inbreeding hurts all other species to different extents, why not insects too ?
Janie.
Here's the deal on roaches. Roaches have so little genetic variation compared to humans that they do not suffer from inbreeding. Their DNA is much stronger than other animals in this respect and they do not suffer from inbreeding. In some roach colonies you may notice smaller adults and this is because the new adults who are smaller because they are younger and the bigger roaches can push them around, produce smaller offspring and so on and so forth. It is related to food competition, not inbreeding as some people think. I have not personally experienced this phenomenon.
I don't know how many generations it would take for inbreeding to occur. I know that with many Tarantulas a brother and sister could be bred together for 7 generations before there were ill effects. Nature has made this an impossibility in normal conditions because of the different maturity rates, but this can be manipulated in captivity. Why someone would go to the trouble I do not know.
You will be good to go with just one source. Most of the roaches in America are ultimately related to each other in some way however distantly anyhow.
I reads some where that it take up to 6 years for roaches to start showing signs of inbreeding but I don't really know if its true. I like to think that adding fresh blood every now and again is a good thing, every couple years I find someone to do a male trade with.