Ectoparasites differ from endoparasites in that they:

Feed on the external surface of the host organism.

Ectoparasites are parasites that feed on the external surface of the host organism. They establish themselves on the outer body of the host and obtain their nutrition from the host's external resources. Examples of ectoparasites include lice on humans, ticks on dogs, and copepods infesting marine fish. These parasites rely on the host's body for their survival and reproduction.

On the other hand, endoparasites are parasites that live inside the host's body at different sites. They inhabit organs or tissues such as the liver, kidney, lungs, red blood cells, and other internal locations. Endoparasites have a more intimate relationship with the host, and their life cycles are often more complex and specialized. They have adapted to survive and reproduce within the host's internal environment.

In summary, ectoparasites feed on the external surface of the host and include examples like lice, ticks, and copepods. They establish a close association with the host's outer body. Endoparasites, on the other hand, live inside the host's body and occupy specific sites or organs. Their life cycles are typically more complex, and they exhibit specialized adaptations for survival and reproduction within the host.