Hybridization in Acropora

[Pedro Alcolado]

Dear listers,
I was fascinated reading Vollmer and Palumbi´s recent paper on hybridization
of Acropora palmata and cervicornis. It establishes clearly and convincingly
the facts of that issue. But reading this paper I remembered an anecdote of
mine. A few years ago I was visisting quite frequently (for different
reasons, once staying 10 days there working on sponges) the nice Aquarium of
Xcaret, Cancun. I was witness of something I think is amazing. In the big
bowl representing the reef crest, there was a trasplanted Acropora palmata
colony (the biggest one among others). There was full illumination and a
wave simulator, with good water circulation there. I was able to observe how
that colony was slowly being transformed in a prolifera bushy-palmate like
fenotype. The ends of the palmate branches began to show short arising (in
the same plane of the branch top) acute branches typical of prolifera, and
the skeleton remaining between them becoming quite traslucent (looking like
a duck foot illuminated at the opposite site). I wonder what was the final
outcome of this gradual transformation. I observed that about 4 years (maybe
less or more, I do not remember exactly) after I saw this colony for the
first time. I would suggest that appart from well proved genetically derived
prolifera like fenotypes, some kinds of changes in environmental variables
(at least in acquarium conditions) would be able to lead also to the same
bushy-palmate fenotype (maybe due to weaker hidrodynamic regime). Really
interesting, no?
Best wishes,
Pedro Alcolado