I found this on a site:
http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2827/L-278web.pdf
Nothing about a symbiotic relationship, and actually suggests removing them.
Good thing I only have 8 adults to clean, should be easy enough to make sure the future generations remain mite free. I wonder if I will have to do them again if there are eggs left behind?
"After you have had your colony or individual
roaches for a while, you may begin to notice tiny
light-colored creatures crawling on the roaches.
Similar to dogs getting fleas, the MHC sometimes
carries mites. These mites only live on the roaches
and will not harm them or live on humans.
Often
their presence indicates a problem with sanitation
within the cage. (no surprise given the tank they came from)Leaving food or dead roaches
in the living environment can attract these mites
and provide a medium for their survival. Mites
can be removed by gently shaking the roach in a
plastic bag with a small amount of flour added.
The mites fall off the roach and into the flour.
Remove the roach, then tie up and discard the
bag. Gently spray the excess flour off the roach
with plain water from a plant mister or wash bottle.
Mites may also be removed by brushing the roach
with a small paintbrush. Repeat the treatment if
mites reappear. Do not attempt to use a miticide
to kill the mites, since this will also kill your pet."