Relationship between parasites and their hosts is often compared to the relationship between predator and prey.
1. In both these relationships, only one partner is benefited whereas the other is harmed.
2. Predator hunts the prey and obtains its nutrition. Similarly, a parasite feeds on the resources of the host and weakens or kills it.
3. Parasites help to control the population size of host. Similarly, predator control the population size of prey.
4. Both these interactions are type of density-dependent limiting factors.