ECOLOGICAL IMMUNOLOGY - COSTLY PARASITE DEFENSES AND TRADE-OFFS IN EVOLUTIONARY ECOLOGY

In the face of continuous threats from parasites, hosts have evolved a n elaborate series of preventative and controlling measures - the immu ne system - in order to reduce the fitness costs of parasitism. Howeve r, these measures do have associated costs. Viewing an individual's im mune response to parasites as being subject to optimization in the fac e of other demands offers potential insights into mechanisms of life h istory trade-offs, sexual selection, parasite-mediated selection and p opulation dynamics. We discuss some recent results that have been obta ined by practitioners of this approach in natural and semi-natural pop ulations, and suggest some ways ire which this field may progress in t he near future.