Nancy G. wrote:
In the wild they are often colonized by ants. Clearly this is not a
desirable condition in a greenhouse. The acidic fertilizer serves as a
substitute for the conditions the ant colony creates, or at least
that's my understanding of the situation.

J. Del Col

That's interesting. I had cymbidium that had its best blooms on it
while ants were living the pot. Afterwards I didn't know whether it
was the acid from the ants, aeration from their activity, or more
organic type fertilizer from their waste.

Probably all three. In addition, ants are fiercely territorial and
will drive off or kill any insect pests that threaten "their" plant,
unless, of course, the ants are honeydew feeders that "farm" aphids or
scale.

Some --Myrmecophilia-- (Schomburgkia) orchids have a beneficial
relationship with ants, too, as their latin generic name implies.

J. Del Col