Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/197934
Type: Artigo de periódico
Title: Network Analysis Reveals Contrasting Effects Of Intraspecific Competition On Individual Vs. Population Diets.
Author: Araújo, Márcio S
Guimarães, Paulo R
Svanbäck, Richard
Pinheiro, Aluisio
Guimarães, Paulo
Dos Reis, Sérgio F
Bolnick, Daniel I
Abstract: Optimal foraging theory predicts that individuals should become more opportunistic when intraspecific competition is high and preferred resources are scarce. This density-dependent diet shift should result in increased diet breadth for individuals as they add previously unused prey to their repertoire. As a result, the niche breadth of the population as a whole should increase. In a recent study, R. Svanbäck and D. I. Bolnick confirmed that intraspecific competition led to increased population diet breadth in threespine stickleback (Gasterosteus aculeatus). However, individual diet breadth did not expand as resource levels declined. Here, we present a new method based on complex network theory that moves beyond a simple measure of diet breadth, and we use the method to reexamine the stickleback experiment. This method reveals that the population as a whole added new types of prey as stickleback density was increased. However, whereas foraging theory predicts that niche expansion is achieved by individuals accepting new prey in addition to previously preferred prey, we found that a subset of individuals ceased to use their previously preferred prey, even though other members of their population continued to specialize on the original prey types. As a result, populations were subdivided into groups of ecologically similar individuals, with diet variation among groups reflecting phenotype-dependent changes in foraging behavior as prey density declined. These results are consistent with foraging theory if we assume that quantitative trait variation among consumers affects prey preferences, and if cognitive constraints prevent individuals from continuing to use their formerly preferred prey while adding new prey.
Subject: Animals
Body Size
Ecosystem
Feeding Behavior
Food Chain
Fresh Water
Invertebrates
Models, Biological
Smegmamorpha
Citation: Ecology. v. 89, n. 7, p. 1981-93, 2008-Jul.
Rights: aberto
Identifier DOI: 
Address: http://www.ncbi.nlm.nih.gov/pubmed/18705384
Date Issue: 2008
Appears in Collections:Unicamp - Artigos e Outros Documentos

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