English: The five processes of host-parasite associations in which speciation occurs or does not occur.

From top to bottom:

• Cospeciation occurs when both the host and parasite speciate concurrently
• Speciation occurs by the parasite switching hosts and evolves in reproductive isolation
• The parasite speciates on the same host due to another factor unrelated to the host
• The parasite goes extinct on a host
• The host speciates but the parasite does not end up reproductively isolated (in this case, the parasite may end up on both species, not shown in picture)