Some host species of hyperparasites do not necessarily have a fixed
ecological strategy but rather exist on an ecological continuum during
their life cycle, e.g., ranging from parasitism to saprotrophism. This
can be illustrated by Armillaria spp., which are necrotrophs on
various tree species. Once the host tree has died, Armillaria switches to a saprotrophic strategy, decaying the same tree substrate. Armillaria species themselves have been recorded as hosts for at
least two agaricioid mycoparasites, namely Collybia cookei and Entoloma abortivum (see below). Nomenclatural issues may also
arise when hyperparasites have multiple host species, some of which are
parasites themselves whereas others may be saprotrophs. A prime example
of this are species of Trichoderma , which infect both pathogenic
and saprotrophic hosts (Jeffries and Young, 1994). In such cases use of
the term “hyperparasite” maybe situational, depending on the
ecological context of the host. Therefore, a “one-definition-fits-all”
approach is unlikely to encapsulate the diversity of interactions
observed in nature.