||Free-living, individual organisms.
||Parasitism (parasite) - an organism that lives in or on another living organism (the host), from which it obtains food and other requirements. The host does not benefit from the association and is usually harmed by it. (cf. commensalism, mutualism, symbiosis) (McLeod, 1996)
||Parasitic on the outer surface of its host (adapted from Lincoln et al., 1998).
||Parasitic within the tissues or organs of its host.
||Symbiosis, the living together in a constant and definite relationship of two different organisms (cf. commensalism, mutualism, parasite) (Brusca, 1980).
||Mutualism (mutualist) - a symbiosis in which both organisms benefit, frequently a relationship of complete dependence. (Lincoln et al., 1998) (cf. symbiosis, commensalism, parasite).
||Inquilinism (inquilinist) - symbiotic association in which one symbiont lives in close association with another, generally in the tube or burrow or actually within a body chamber of the host (Brusca, 1980).
||Commensalism (commensal) - symbiosis (q.v.) in which one species derives benefit from a common food supply, whilst the other species is not adversely affected (Lincoln et al., 1998).