One last question for today! :P

I was wondering if anyone else has had a bad experience with rearing harlequin cockroaches? I have kept a steady, small number of them over the past 2 years or so, because as the new eggs hatch, the old roaches die. I'd consider this normal, however they not only lay few eggs, it seems that they only live for a couple of months, and they die in a strange way... the pretty, white parts of their patterning turn a darker color, then they begin eating off their own legs & antennae, and curl up on the bottom of their enclosure, their abdomens pulsating right before they die. I am worried this may be a parasite or some kind of disease exclusive to the Harlequin roaches? I hate to see them slowly suffering like this without having a clue what I could do to help them.

Thanks for any help. I know this is a somewhat common problem, as I do recall reading about this before getting these, but I can't seem to find the information anymore.