I recently posed this question to Dr. Gary Rosenberg at the Academy of Natural
Sciences, but I would like to draw on the knowledge of this group...I will do
my best to give the "Cliff Notes" version of the delimma...
 
 I recently returned from studying at the Duke University Marine Lab in which
I began a bit of solo research on the relationship between the sea whip
(Leptogorina virgulata) and the commensal snail, Simnialena uniplicata
(Sowerby, 1848).  I have found very little written on either organism (I have
done abstract & journal searches, etc) and am in need of further information.
I performed a series of experiments in which I placed the snails from one
color sea whip onto another color.  I did this with 25 Simnialena from a whip
with orange color and 25 from a yellow variant.  I also had a control group of
25 which I removed from their original Leptogorina and replaced on the same
stalks.  Within 12 hours (actually less) the snails that had been placed on
the different colored Leptogorina had died while the control group were still
thriving.  Every effort was made to keep conditions exact.
If anyone has any knowledge or thoughts to share, please do...
 
Cheers,
Brian S. Rayburn