only one organism benefits from this association without causing any harm to the second organism e.g. fish which live within the tentacles of sea anemone (fish obtains a degree of protection)

organisms of different species both benefit from the interaction e.g., honey-bee and flowering plant

only one organism benefits from the interaction but this to the detriment of the other

At some or all stages of life cycle cannot survive in the absence of the host

Lives in/on the outer body surfaces of the host e.g., fleas, lice, ticks, mites

Not usually used by parasite but still favours life cycle completion e.g., liver fluke (Fasciola hepatica) infection in humans

Host in which the parasite cannot complete the life cycle. e.g., Toxocara infection in humans

Temporary host used in the absence of natural host e.g., human trypanosomes reservoir in cattle and antelope

Host the parasite without any further development e.g., rodent in cat or dog lungworms

A vector which mechanically spreads parasite and is not utilised in the parasite life cycle e.g., Tabanid flies (horse fly, deer fly)

A vector needed by the parasite to complete part of its life cycle e.g., Glossina pallipides transmits T. brucei brucei causing trypanosomiasis (nagana disease) in cattle