The role is realized in processes in which the host makes the relevant environmental resources available to its partner in symbiosis. A bearer of a symbiont host role is bearer also of a symbiont role.

The relevant environmental resources may include nutrient resources, warmth, or moisture.

A host role borne by an organism in virtue of the fact that its extended organism contains a second organism and provides an environment supportive for the survival, growth, maturation, or reproduction of that organism.

Albert Goldfain

Lindsay Cowell

Alexander Diehl