10.1. Introduction

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.

Alexei Sharov 1/12/96