Feedback effects between the food chain and induced defense strategies

Donald L. Deangelis, Matthijs Vos, Wolf M. Mooij, Peter A. Abrams

Research output: Chapter in Book/Report/Conference proceedingChapter

17 Scopus citations


Recently it has been shown that inducible defenses in species at the bottom and middle of three-species food chains promote stability and typically allow all trophic levels to increase in response to fertilization. However, that past work did not allow prey individuals to optimize their responses to the levels of resources and predator density, and hence ignored the effects of optimal defense induction on trophic structure. In the present work, we studied such feedback effects in a food chain containing a predator, a prey with an inducible defense, and a resource. Both ordinary differential equations and their individual-based analogs were used to investigate food chain behavior under enrichment. The individual-based implementation simulated many competing prey strains, each with a different parameter value for responsiveness to predator density in its function for inducible defense. Eventually, a single prey strain remained. Simulations suggested that the prey evolved toward an evolutionarily stable strategy (ESS) for this defense parameter, which simultaneously produced an ideal free distribution (IFD) of individuals between the defended and undefended states. This was confirmed by further analysis. In our model system with prey defenses at ESS and IFD, only the abundance of the prey responded to enrichment. In contrast, when prey did not use the ESS and a source-sink relation existed between defended and undefended prey types, all trophic levels increased in response to enrichment. This response pattern is frequently observed in the field and laboratory.

Original languageEnglish (US)
Title of host publicationFrom Energetics to Ecosystems
Subtitle of host publicationThe Dynamics and Structure of Ecological Systems
PublisherSpringer Netherlands
Number of pages23
ISBN (Print)1402053363, 9781402053368
StatePublished - Dec 1 2007

ASJC Scopus subject areas

  • Environmental Science(all)


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