DUBIA AGE

[rachela616]

I have a great colony that has been up and going for about a year and a half now, I was wondering if there is a way to tell my adult females apart, the younger reproducing ones from the older ones. I have noticed some of my females have started to die randomly (I assume from old age) because I haven't had a drastic die off, it's really just one here and there that I find dead. But I have noticed that the females that have died have been super dark brown or almost black, is this an indication of old age when comparing them to my lighter colored females? Any feedback would be great, as I am having difficulties finding the answer to this question online.

Thanks!