<P> Like all ecological interactions, commensalisms vary in strength and duration from intimate, long - lived symbioses to brief, weak interactions through intermediaries . </P> <P> Phoresy is one animal attached to another exclusively for transport, mainly arthropods, examples of which are mites on insects (such as beetles, flies or bees), pseudoscorpions on mammals or beetles, and millipedes on birds . Phoresy can be either obligate or facultative (induced by environmental conditions). </P> <P> Inquilinism is the use of a second organism for permanent housing . Examples are epiphytic plants (such as many orchids) that grow on trees, or birds that live in holes in trees . </P> <P> Metabiosis is a more indirect dependency, in which one organism creates or prepares a suitable environment for a second . Examples include maggots, which feast and develop on corpses, and hermit crabs, which use gastropod shells to protect their bodies . </P>

Why is the interdependence of the worms and plants an example of commensalism