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Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal

While sexual segregation is expected in highly dimorphic species, the local environment is a major factor driving the degree of resource partitioning within a population. Sexual and individual niche segregation was investigated in the Australian fur seal (Arctocephalus pusillus doriferus), which is...

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Autores principales: Kernaléguen, Laëtitia, Cherel, Yves, Knox, Travis C., Baylis, Alastair M. M., Arnould, John P. Y.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4526469/
https://www.ncbi.nlm.nih.gov/pubmed/26244371
http://dx.doi.org/10.1371/journal.pone.0133018
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author Kernaléguen, Laëtitia
Cherel, Yves
Knox, Travis C.
Baylis, Alastair M. M.
Arnould, John P. Y.
author_facet Kernaléguen, Laëtitia
Cherel, Yves
Knox, Travis C.
Baylis, Alastair M. M.
Arnould, John P. Y.
author_sort Kernaléguen, Laëtitia
collection PubMed
description While sexual segregation is expected in highly dimorphic species, the local environment is a major factor driving the degree of resource partitioning within a population. Sexual and individual niche segregation was investigated in the Australian fur seal (Arctocephalus pusillus doriferus), which is a benthic foraging species restricted to the shallow continental shelf region of south-eastern Australia. Tracking data and the isotopic values of plasma, red blood cells and whiskers were combined to document spatial and dietary niche segregation throughout the year. Tracking data indicated that, in winter, males and females overlapped in their foraging habitat. All individuals stayed within central Bass Strait, relatively close (< 220 km) to the breeding colony. Accordingly, both genders exhibited similar plasma and red cell δ(13)C values. However, males exhibited greater δ(13)C intra-individual variation along the length of their whisker than females. This suggests that males exploited a greater diversity of foraging habitats throughout the year than their female counterparts, which are restricted in their foraging grounds by the need to regularly return to the breeding colony to suckle their pup. The degree of dietary sexual segregation was also surprisingly low, both sexes exhibiting a great overlap in their δ(15)N values. Yet, males displayed higher δ(15)N values than females, suggesting they fed upon a higher proportion of higher trophic level prey. Given that males and females exploit different resources (mainly foraging habitats), the degree of individual specialisation might differ between the sexes. Higher degrees of individual specialisation would be expected in males which exploit a greater range of resources. However, comparable levels of inter-individual variation in δ(15)N whisker values were found in the sampled males and females, and, surprisingly, all males exhibited similar seasonal and inter-annual variation in their δ(13)C whisker values, suggesting they all followed the same general dispersion pattern throughout the year.
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spelling pubmed-45264692015-08-12 Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal Kernaléguen, Laëtitia Cherel, Yves Knox, Travis C. Baylis, Alastair M. M. Arnould, John P. Y. PLoS One Research Article While sexual segregation is expected in highly dimorphic species, the local environment is a major factor driving the degree of resource partitioning within a population. Sexual and individual niche segregation was investigated in the Australian fur seal (Arctocephalus pusillus doriferus), which is a benthic foraging species restricted to the shallow continental shelf region of south-eastern Australia. Tracking data and the isotopic values of plasma, red blood cells and whiskers were combined to document spatial and dietary niche segregation throughout the year. Tracking data indicated that, in winter, males and females overlapped in their foraging habitat. All individuals stayed within central Bass Strait, relatively close (< 220 km) to the breeding colony. Accordingly, both genders exhibited similar plasma and red cell δ(13)C values. However, males exhibited greater δ(13)C intra-individual variation along the length of their whisker than females. This suggests that males exploited a greater diversity of foraging habitats throughout the year than their female counterparts, which are restricted in their foraging grounds by the need to regularly return to the breeding colony to suckle their pup. The degree of dietary sexual segregation was also surprisingly low, both sexes exhibiting a great overlap in their δ(15)N values. Yet, males displayed higher δ(15)N values than females, suggesting they fed upon a higher proportion of higher trophic level prey. Given that males and females exploit different resources (mainly foraging habitats), the degree of individual specialisation might differ between the sexes. Higher degrees of individual specialisation would be expected in males which exploit a greater range of resources. However, comparable levels of inter-individual variation in δ(15)N whisker values were found in the sampled males and females, and, surprisingly, all males exhibited similar seasonal and inter-annual variation in their δ(13)C whisker values, suggesting they all followed the same general dispersion pattern throughout the year. Public Library of Science 2015-08-05 /pmc/articles/PMC4526469/ /pubmed/26244371 http://dx.doi.org/10.1371/journal.pone.0133018 Text en © 2015 Kernaléguen et al http://creativecommons.org/licenses/by/4.0/ This 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 properly credited.
spellingShingle Research Article
Kernaléguen, Laëtitia
Cherel, Yves
Knox, Travis C.
Baylis, Alastair M. M.
Arnould, John P. Y.
Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal
title Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal
title_full Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal
title_fullStr Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal
title_full_unstemmed Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal
title_short Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal
title_sort sexual niche segregation and gender-specific individual specialisation in a highly dimorphic marine mammal
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4526469/
https://www.ncbi.nlm.nih.gov/pubmed/26244371
http://dx.doi.org/10.1371/journal.pone.0133018
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