Can foraging ecology drive the evolution of body size in a diving endotherm?

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dc.contributor.authorCook, Timothée Ren_ZA
dc.contributor.authorLescroël, Amélieen_ZA
dc.contributor.authorCherel, Yvesen_ZA
dc.contributor.authorKato, Akikoen_ZA
dc.contributor.authorBost, Charles-Andréen_ZA
dc.date.accessioned2015-12-20T16:05:59Z
dc.date.available2015-12-20T16:05:59Z
dc.date.issued2013en_ZA
dc.description.abstractWithin a single animal species, different morphs can allow for differential exploitation of foraging niches between populations, while sexual size dimorphism can provide each sex with access to different resources. Despite being potentially important agents of evolution, resource polymorphisms, and the way they operate in wild populations, remain poorly understood. In this study, we examine how trophic factors can select for different body sizes between populations and sexes in a diving endotherm. Dive depth and duration are positively related to body size in diving birds and mammals, a relationship explained by a lower mass-specific metabolic rate and greater oxygen stores in larger individuals. Based on this allometry, we predict that selection for exploiting resources situated at different depths can drive the evolution of body size in species of diving endotherms at the population and sexual level. To test this prediction, we studied the foraging ecology of Blue-eyed Shags, a group of cormorants with male-biased sexual size dimorphism from across the Southern Ocean. We found that mean body mass and relative difference in body mass between sexes varied by up to 77% and 107% between neighbouring colonies, respectively. Birds from colonies with larger individuals dived deeper than birds from colonies with smaller individuals, when accounting for sex. In parallel, males dived further offshore and deeper than females and the sexual difference in dive depth reflected the level of sexual size dimorphism at each colony. We argue that body size in this group of birds is under intense selection for diving to depths of profitable benthic prey patches and that, locally, sexual niche divergence selection can exaggerate the sexual size dimorphism of Blue-eyed Shags initially set up by sexual selection. Our findings suggest that trophic resources can select for important geographic micro-variability in body size between populations and sexes.en_ZA
dc.identifier.apacitationCook, T. R., Lescroël, A., Cherel, Y., Kato, A., & Bost, C. (2013). Can foraging ecology drive the evolution of body size in a diving endotherm?. <i>PLoS One</i>, http://hdl.handle.net/11427/15922en_ZA
dc.identifier.chicagocitationCook, Timothée R, Amélie Lescroël, Yves Cherel, Akiko Kato, and Charles-André Bost "Can foraging ecology drive the evolution of body size in a diving endotherm?." <i>PLoS One</i> (2013) http://hdl.handle.net/11427/15922en_ZA
dc.identifier.citationCook, T. R., Lescroël, A., Cherel, Y., Kato, A., & Bost, C. A. (2013). Can foraging ecology drive the evolution of body size in a diving endotherm. PloS one, 8(2), e56297. doi:10.1371/journal.pone.0056297en_ZA
dc.identifier.ris TY - Journal Article AU - Cook, Timothée R AU - Lescroël, Amélie AU - Cherel, Yves AU - Kato, Akiko AU - Bost, Charles-André AB - Within a single animal species, different morphs can allow for differential exploitation of foraging niches between populations, while sexual size dimorphism can provide each sex with access to different resources. Despite being potentially important agents of evolution, resource polymorphisms, and the way they operate in wild populations, remain poorly understood. In this study, we examine how trophic factors can select for different body sizes between populations and sexes in a diving endotherm. Dive depth and duration are positively related to body size in diving birds and mammals, a relationship explained by a lower mass-specific metabolic rate and greater oxygen stores in larger individuals. Based on this allometry, we predict that selection for exploiting resources situated at different depths can drive the evolution of body size in species of diving endotherms at the population and sexual level. To test this prediction, we studied the foraging ecology of Blue-eyed Shags, a group of cormorants with male-biased sexual size dimorphism from across the Southern Ocean. We found that mean body mass and relative difference in body mass between sexes varied by up to 77% and 107% between neighbouring colonies, respectively. Birds from colonies with larger individuals dived deeper than birds from colonies with smaller individuals, when accounting for sex. In parallel, males dived further offshore and deeper than females and the sexual difference in dive depth reflected the level of sexual size dimorphism at each colony. We argue that body size in this group of birds is under intense selection for diving to depths of profitable benthic prey patches and that, locally, sexual niche divergence selection can exaggerate the sexual size dimorphism of Blue-eyed Shags initially set up by sexual selection. Our findings suggest that trophic resources can select for important geographic micro-variability in body size between populations and sexes. DA - 2013 DB - OpenUCT DO - 10.1371/journal.pone.0056297 DP - University of Cape Town J1 - PLoS One LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - Can foraging ecology drive the evolution of body size in a diving endotherm? TI - Can foraging ecology drive the evolution of body size in a diving endotherm? UR - http://hdl.handle.net/11427/15922 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/15922
dc.identifier.urihttp://dx.doi.org/10.1371/journal.pone.0056297
dc.identifier.vancouvercitationCook TR, Lescroël A, Cherel Y, Kato A, Bost C. Can foraging ecology drive the evolution of body size in a diving endotherm?. PLoS One. 2013; http://hdl.handle.net/11427/15922.en_ZA
dc.language.isoengen_ZA
dc.publisherPublic Library of Scienceen_ZA
dc.publisher.departmentPercy FitzPatrick Institute of African Ornithologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.rightsThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en_ZA
dc.rights.holder© 2013 Cook et alen_ZA
dc.rights.urihttp://creativecommons.org/licenses/by/4.0en_ZA
dc.sourcePLoS Oneen_ZA
dc.source.urihttp://journals.plos.org/plosoneen_ZA
dc.subject.otherPhysiological parametersen_ZA
dc.subject.otherBirdsen_ZA
dc.subject.otherForagingen_ZA
dc.subject.otherSexual selectionen_ZA
dc.subject.otherEcological nichesen_ZA
dc.subject.otherMarine fishen_ZA
dc.subject.otherPenguinsen_ZA
dc.subject.otherPredationen_ZA
dc.titleCan foraging ecology drive the evolution of body size in a diving endotherm?en_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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