Predation and parasitism are examples of antagonistic ecological interactions in which one species takes advantage of another species. Predators (see a picture) use their prey as a source of food only, whereas parasites (see a picture) use their hosts both as a food and as a habitat. Predation and parasitism are stage-specific interactions rather than species-specific. Many species are predators or parasites only on specific stages in their life cycle.
Importance of the study of predation and parasitism:
- In many species predation and parasitism are dominating among ecological processes. Dynamics of these populations cannot be predicted and understood without considering natural enemies.
- Pest species of insects and weeds can be suppressed by introduction of natural enemies or by inundative release of natural enemies (biological control).
- Natural enemies may cause side effects in pesticide applications. The numbers of arthropod natural enemies may be reduced due to pesticide treatment which may result in increasing of pest populations.