Sex-based differences in Adélie Penguin (Pygoscelis adeliae) chick growth rates and diet

 

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dc.contributor.author Jennings, Scott en_ZA
dc.contributor.author Varsani, Arvind en_ZA
dc.contributor.author Dugger, Katie M en_ZA
dc.contributor.author Ballard, Grant en_ZA
dc.contributor.author Ainley, David G en_ZA
dc.date.accessioned 2016-03-08T10:55:34Z
dc.date.available 2016-03-08T10:55:34Z
dc.date.issued 2016 en_ZA
dc.identifier.citation Jennings, S., Varsani, A., Dugger, K. M., Ballard, G., & Ainley, D. G. (2016). Sex-based differences in Adélie Penguin (Pygoscelis adeliae) chick growth rates and diet. PLOS ONE, 11(3), e0149090. doi:10.1371/journal.pone.0149090 en_ZA
dc.identifier.uri http://dx.doi.org/10.1371/journal.pone.0149090 en_ZA
dc.identifier.uri http://hdl.handle.net/11427/17575
dc.description.abstract Sexually size-dimorphic species must show some difference between the sexes in growth rate and/or length of growing period. Such differences in growth parameters can cause the sexes to be impacted by environmental variability in different ways, and understanding these differences allows a better understanding of patterns in productivity between individuals and populations. We investigated differences in growth rate and diet between male and female Adélie Penguin ( Pygoscelis adeliae ) chicks during two breeding seasons at Cape Crozier, Ross Island, Antarctica. Adélie Penguins are a slightly dimorphic species, with adult males averaging larger than adult females in mass (~11%) as well as bill (~8%) and flipper length (~3%). We measured mass and length of flipper, bill, tibiotarsus, and foot at 5-day intervals for 45 male and 40 female individually-marked chicks. Chick sex was molecularly determined from feathers. We used linear mixed effects models to estimate daily growth rate as a function of chick sex, while controlling for hatching order, brood size, year, and potential variation in breeding quality between pairs of parents. Accounting for season and hatching order, male chicks gained mass an average of 15.6 g d -1 faster than females. Similarly, growth in bill length was faster for males, and the calculated bill size difference at fledging was similar to that observed in adults. There was no evidence for sex-based differences in growth of other morphological features. Adélie diet at Ross Island is composed almost entirely of two species--one krill ( Euphausia crystallorophias ) and one fish ( Pleuragramma antarctica ), with fish having a higher caloric value. Using isotopic analyses of feather samples, we also determined that male chicks were fed a higher proportion of fish than female chicks. The related differences in provisioning and growth rates of male and female offspring provides a greater understanding of the ways in which ecological factors may impact the two sexes differently. en_ZA
dc.language.iso eng en_ZA
dc.publisher Public Library of Science en_ZA
dc.rights 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 credited. en_ZA
dc.rights.uri http://creativecommons.org/licenses/by/4.0 en_ZA
dc.source PLoS One en_ZA
dc.source.uri http://journals.plos.org/plosone en_ZA
dc.subject.other Penguins en_ZA
dc.subject.other Diet en_ZA
dc.subject.other Feathers en_ZA
dc.subject.other Marine fish en_ZA
dc.subject.other Antarctica en_ZA
dc.subject.other Foraging en_ZA
dc.subject.other Trophic interactions en_ZA
dc.subject.other Birds en_ZA
dc.title Sex-based differences in Adélie Penguin (Pygoscelis adeliae) chick growth rates and diet en_ZA
dc.type Journal Article en_ZA
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Health Sciences en_ZA
dc.publisher.department Division of Medical Biochemistry en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Jennings, S., Varsani, A., Dugger, K. M., Ballard, G., & Ainley, D. G. (2016). Sex-based differences in Adélie Penguin (Pygoscelis adeliae) chick growth rates and diet. <i>PLoS One</i>, http://hdl.handle.net/11427/17575 en_ZA
dc.identifier.chicagocitation Jennings, Scott, Arvind Varsani, Katie M Dugger, Grant Ballard, and David G Ainley "Sex-based differences in Adélie Penguin (Pygoscelis adeliae) chick growth rates and diet." <i>PLoS One</i> (2016) http://hdl.handle.net/11427/17575 en_ZA
dc.identifier.vancouvercitation Jennings S, Varsani A, Dugger KM, Ballard G, Ainley DG. Sex-based differences in Adélie Penguin (Pygoscelis adeliae) chick growth rates and diet. PLoS One. 2016; http://hdl.handle.net/11427/17575. en_ZA
dc.identifier.ris TY - Journal Article AU - Jennings, Scott AU - Varsani, Arvind AU - Dugger, Katie M AU - Ballard, Grant AU - Ainley, David G AB - Sexually size-dimorphic species must show some difference between the sexes in growth rate and/or length of growing period. Such differences in growth parameters can cause the sexes to be impacted by environmental variability in different ways, and understanding these differences allows a better understanding of patterns in productivity between individuals and populations. We investigated differences in growth rate and diet between male and female Adélie Penguin ( Pygoscelis adeliae ) chicks during two breeding seasons at Cape Crozier, Ross Island, Antarctica. Adélie Penguins are a slightly dimorphic species, with adult males averaging larger than adult females in mass (~11%) as well as bill (~8%) and flipper length (~3%). We measured mass and length of flipper, bill, tibiotarsus, and foot at 5-day intervals for 45 male and 40 female individually-marked chicks. Chick sex was molecularly determined from feathers. We used linear mixed effects models to estimate daily growth rate as a function of chick sex, while controlling for hatching order, brood size, year, and potential variation in breeding quality between pairs of parents. Accounting for season and hatching order, male chicks gained mass an average of 15.6 g d -1 faster than females. Similarly, growth in bill length was faster for males, and the calculated bill size difference at fledging was similar to that observed in adults. There was no evidence for sex-based differences in growth of other morphological features. Adélie diet at Ross Island is composed almost entirely of two species--one krill ( Euphausia crystallorophias ) and one fish ( Pleuragramma antarctica ), with fish having a higher caloric value. Using isotopic analyses of feather samples, we also determined that male chicks were fed a higher proportion of fish than female chicks. The related differences in provisioning and growth rates of male and female offspring provides a greater understanding of the ways in which ecological factors may impact the two sexes differently. DA - 2016 DB - OpenUCT DO - 10.1371/journal.pone.0149090 DP - University of Cape Town J1 - PLoS One LK - https://open.uct.ac.za PB - University of Cape Town PY - 2016 T1 - Sex-based differences in Adélie Penguin (Pygoscelis adeliae) chick growth rates and diet TI - Sex-based differences in Adélie Penguin (Pygoscelis adeliae) chick growth rates and diet UR - http://hdl.handle.net/11427/17575 ER - en_ZA


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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 credited. Except where otherwise noted, this item's license is described as 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 credited.