Poly-symbiosis? What's the name for this?
A mutually beneficial relationship between two species is not called symbiosis, but is rather called &quot;mutualism.&quot; The benefit is measured in terms of fitness; a combination of survival and reproduction. Symbiosis is the degree to which species are &quot;together,&quot; which is used in terms of physical proximity or degree of dependency. Pathogens, for instance, have a symbiotic relationship with their hosts and physiologically depend on their hosts by feeding on them. Mutualism and symbiosis are often conflated, and should not be.
Let's dissect: &quot;If multiple symbiotic relationships exist with a single common (dominant) species, is this called 'farming'?&quot; It seems like you mean, if members of the same species increase each other's fitness. Reciprocal fitness benefits between species is called mutualism, and within species is cooperation. There are important differences between mutualism and cooperation from evolutionary points of view and they have vastly different intellectual histories. None of this is really called &quot;farming,&quot; except for some ant-insect mutualisms, where ants raise and protect aphids for a reward (honeydew; i.e., plant sugars secreted by some insects).