Dietary divergence is associated with increased intra-specific competition in a marine predator

Abstract Optimal foraging theory predicts that when food is plentiful all individuals should take a small range of preferred prey types, but as competition increases less preferred prey will be included in the diet. This dietary switching may not be uniform among individuals, which produces discrete...

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Autores principales:	Norman Ratcliffe, Stacey Adlard, Gabrielle Stowasser, Rona McGill
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2018
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/722914f46454410c997b496c4c098df4
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spelling	oai:doaj.org-article:722914f46454410c997b496c4c098df42021-12-02T11:41:02ZDietary divergence is associated with increased intra-specific competition in a marine predator10.1038/s41598-018-25318-72045-2322https://doaj.org/article/722914f46454410c997b496c4c098df42018-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-25318-7https://doaj.org/toc/2045-2322Abstract Optimal foraging theory predicts that when food is plentiful all individuals should take a small range of preferred prey types, but as competition increases less preferred prey will be included in the diet. This dietary switching may not be uniform among individuals, which produces discrete dietary clusters. We tested this hypothesis for gentoo penguins at Bird Island, South Georgia, using stable isotope analysis and biologging. Competition, in the form of the density of foraging dives, increased markedly from incubation to chick-rearing owing to increased foraging effort. Birds responded behaviourally by exploiting a greater portion of the available foraging radius and increasing dive depths. Dietary niche width doubled and two discrete dietary clusters appeared; one comprising birds that consumed mostly krill and another that ate a greater proportion of demersal fish. There were no differences in morphology between the dietary classes, but birds in the fish class had a tendency to dive deeper, which suggests a behavioural basis for specialization. Our findings are consistent with the hypothesis that intra-specific competition expands the population’s dietary niche width and drives divergence in diets among individuals.Norman RatcliffeStacey AdlardGabrielle StowasserRona McGillNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-10 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Norman Ratcliffe Stacey Adlard Gabrielle Stowasser Rona McGill Dietary divergence is associated with increased intra-specific competition in a marine predator
description	Abstract Optimal foraging theory predicts that when food is plentiful all individuals should take a small range of preferred prey types, but as competition increases less preferred prey will be included in the diet. This dietary switching may not be uniform among individuals, which produces discrete dietary clusters. We tested this hypothesis for gentoo penguins at Bird Island, South Georgia, using stable isotope analysis and biologging. Competition, in the form of the density of foraging dives, increased markedly from incubation to chick-rearing owing to increased foraging effort. Birds responded behaviourally by exploiting a greater portion of the available foraging radius and increasing dive depths. Dietary niche width doubled and two discrete dietary clusters appeared; one comprising birds that consumed mostly krill and another that ate a greater proportion of demersal fish. There were no differences in morphology between the dietary classes, but birds in the fish class had a tendency to dive deeper, which suggests a behavioural basis for specialization. Our findings are consistent with the hypothesis that intra-specific competition expands the population’s dietary niche width and drives divergence in diets among individuals.
format	article
author	Norman Ratcliffe Stacey Adlard Gabrielle Stowasser Rona McGill
author_facet	Norman Ratcliffe Stacey Adlard Gabrielle Stowasser Rona McGill
author_sort	Norman Ratcliffe
title	Dietary divergence is associated with increased intra-specific competition in a marine predator
title_short	Dietary divergence is associated with increased intra-specific competition in a marine predator
title_full	Dietary divergence is associated with increased intra-specific competition in a marine predator
title_fullStr	Dietary divergence is associated with increased intra-specific competition in a marine predator
title_full_unstemmed	Dietary divergence is associated with increased intra-specific competition in a marine predator
title_sort	dietary divergence is associated with increased intra-specific competition in a marine predator
publisher	Nature Portfolio
publishDate	2018
url	https://doaj.org/article/722914f46454410c997b496c4c098df4
work_keys_str_mv	AT normanratcliffe dietarydivergenceisassociatedwithincreasedintraspecificcompetitioninamarinepredator AT staceyadlard dietarydivergenceisassociatedwithincreasedintraspecificcompetitioninamarinepredator AT gabriellestowasser dietarydivergenceisassociatedwithincreasedintraspecificcompetitioninamarinepredator AT ronamcgill dietarydivergenceisassociatedwithincreasedintraspecificcompetitioninamarinepredator
_version_	1718395466880647168

Dietary divergence is associated with increased intra-specific competition in a marine predator

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