Roaches getting smaller

[Jeff P]

My B. dubia colony is about 3 generations old and I am starting to notice that the males are starting to mature smaller. Should I be concerned? Is there something I can do?

[Huntsman]

I hate to state the obvious, Jeff, but it might be time to add new - unrelated - stock to the mix.

My own method would be to start a second colony if possible, using 50% new blood and 50% of the old. Keep feeding from the old colony and let things take their normal course.

[Allpet Roaches]

In such a short time it's pretty much impossible that you'd shrink the genetic size of the species. Most likely you're experiencing the results of overcrowding, not a genetic shift. However, over many, many, many generations if you let the smaller males breed (they should be removed and fed off) you could shrink the ultimate size of the male (which may or may not have any effect on the female since size is often sex-linked).

[Matt K]

In such a short time it's pretty much impossible that you'd shrink the genetic size of the species. Most likely you're experiencing the results of overcrowding, not a genetic shift. However, over many, many, many generations if you let the smaller males breed (they should be removed and fed off) you could shrink the ultimate size of the male (which may or may not have any effect on the female since size is often sex-linked).

I had a similar experience with Orangeheads, but it took 10 years and countless generations to make a very slight difference, and then I am not sure if it was that I added some fresh stock or if it was because I moved them to a larger container (probably) that resolved the issue. I think that sometimes when roaches are crowed they can result in a slight reduction in size...