Table 1:

Definitions of terms used to describe the constraint-based null models.

Term	Definition
Labeled	Hosts or parasites are distinguishable
Unlabeled	Hosts or parasites are indistinguishable
Macrostate	Unordered vector of unlabeled parasite abundances. e.g. Given P = 3 and H = 2, the vector {3, 0} is a macrostate
Configuration	Ordered vector of unlabeled parasite abundances. e.g. Given P = 3 an H = 2, the macrostate {3, 0} has two configurations: (3, 0) and (0, 3)
Feasible set	All possible macrostates given P and H. e.g. The feasible set given P = 3 and H = 2 is {{3, 0}, {2, 1}}
Weighted feasible set	Feasible set in which macrostates have particular weights.
Partition model	Weights each macrostate in the feasible set by assuming unla-beled hosts and parasites. All macrostates have equal weights.
Composition model	Weights each macrostate in the feasible set by assuming labeled hosts and unlabeled parasites. Analogously, each macrostate can be realized by multiple configurations.