Phoresy: A relationship between host and commensal involving only passive attachment of the commensal to the surface of the host (e.g., barnacle on whale). The supporting partner must be continuously moving.
Parasitoid: An organism that is parasitic only during its larval stage.
An animal that lives in or on another animal (the host), which it consumes and eventually kills. Hence, parasitoid may be regarded as intermediate between a true parasite and a predator.
Many wasps and other hymenopterans and also some flies, are parasitoids for part of their life cycle, laying their eggs commonly in or on the larvae of other insects. The hatched parasitoids then use the tissue of their host for food during development into free-living adults. At maturation they emerge and usually do cause death of their host (unlike most of the parasites).