Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals
Evolved patterns of resource expenditure for reproduction have resulted in a life history continuum across species. A strictly capital-breeding strategy relies extensively on stored energy for reproduction, whereas income breeding uses energy acquired throughout the reproductive period. However, fac...
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Online Access: | https://eprints.utas.edu.au/3143/ https://eprints.utas.edu.au/3143/1/Oecologia.pdf https://doi.org/10.1007/s00442-007-0888-7 |
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ftunivtasmania:oai:eprints.utas.edu.au:3143 2023-05-15T18:43:22+02:00 Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals Wheatley, KE Bradshaw, CJA Harcourt, RG Hindell, MA 2008 application/pdf https://eprints.utas.edu.au/3143/ https://eprints.utas.edu.au/3143/1/Oecologia.pdf https://doi.org/10.1007/s00442-007-0888-7 en eng https://eprints.utas.edu.au/3143/1/Oecologia.pdf Wheatley, KE, Bradshaw, CJA, Harcourt, RG and Hindell, MA 2008 , 'Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals' , Oecologia, vol. 155, no. 1 , pp. 11-20 , doi:10.1007/s00442-007-0888-7 <http://dx.doi.org/10.1007/s00442-007-0888-7>. cc_utas 270500 Zoology 270600 Physiology Capital breeding - Energy expenditure - Income breeding - Leptonychotes weddellii - Milk energy Article PeerReviewed 2008 ftunivtasmania https://doi.org/10.1007/s00442-007-0888-7 2020-05-30T07:16:52Z Evolved patterns of resource expenditure for reproduction have resulted in a life history continuum across species. A strictly capital-breeding strategy relies extensively on stored energy for reproduction, whereas income breeding uses energy acquired throughout the reproductive period. However, facultative income breeding has been shown in some classically capital-breeding animals, and was originally thought to provide a nutritional refuge for smaller females incapable of securing sufficient reserves during pre-partum foraging. We examined milk composition and milk output for the Weddell seal to determine to what degree lactation was aided by food intake, and what factors contributed to its manifestation. Milk composition was independent of maternal post-partum mass and condition, but did change over lactation. Changes were most likely in response to energetic and nutritional demands of the pup at different stages of development. During early lactation, females fasted and devoted 54.9% of total energy loss to milk production. Later in lactation 30.5% more energy was devoted to milk production and evidence suggested that larger females fed more during lactation than smaller females. It appears that Weddell seals may exhibit a flexible strategy to adjust reproductive investment to local resource levels by taking advantage of periods when prey are occasionally abundant, although it is restricted to larger females possessing the physiological capacity to dive for longer and exploit different resources during lactation. This supports the assumption that although body mass and phylogenetic history explain most of the variation in lactation patterns (20–69%), the remaining variation has likely resulted from physiological adaptations to local environmental conditions. Our study confirms that Weddell seals use a mixed capital–income breeding strategy, and that considerable intraspecific variation exists. Questions remain as to the amount of energy gain derived from the income strategy, and the consequences for pup condition and survival. Article in Journal/Newspaper Weddell Seal Weddell Seals University of Tasmania: UTas ePrints Weddell Oecologia 155 1 11 20 |
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Open Polar |
collection |
University of Tasmania: UTas ePrints |
op_collection_id |
ftunivtasmania |
language |
English |
topic |
270500 Zoology 270600 Physiology Capital breeding - Energy expenditure - Income breeding - Leptonychotes weddellii - Milk energy |
spellingShingle |
270500 Zoology 270600 Physiology Capital breeding - Energy expenditure - Income breeding - Leptonychotes weddellii - Milk energy Wheatley, KE Bradshaw, CJA Harcourt, RG Hindell, MA Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals |
topic_facet |
270500 Zoology 270600 Physiology Capital breeding - Energy expenditure - Income breeding - Leptonychotes weddellii - Milk energy |
description |
Evolved patterns of resource expenditure for reproduction have resulted in a life history continuum across species. A strictly capital-breeding strategy relies extensively on stored energy for reproduction, whereas income breeding uses energy acquired throughout the reproductive period. However, facultative income breeding has been shown in some classically capital-breeding animals, and was originally thought to provide a nutritional refuge for smaller females incapable of securing sufficient reserves during pre-partum foraging. We examined milk composition and milk output for the Weddell seal to determine to what degree lactation was aided by food intake, and what factors contributed to its manifestation. Milk composition was independent of maternal post-partum mass and condition, but did change over lactation. Changes were most likely in response to energetic and nutritional demands of the pup at different stages of development. During early lactation, females fasted and devoted 54.9% of total energy loss to milk production. Later in lactation 30.5% more energy was devoted to milk production and evidence suggested that larger females fed more during lactation than smaller females. It appears that Weddell seals may exhibit a flexible strategy to adjust reproductive investment to local resource levels by taking advantage of periods when prey are occasionally abundant, although it is restricted to larger females possessing the physiological capacity to dive for longer and exploit different resources during lactation. This supports the assumption that although body mass and phylogenetic history explain most of the variation in lactation patterns (20–69%), the remaining variation has likely resulted from physiological adaptations to local environmental conditions. Our study confirms that Weddell seals use a mixed capital–income breeding strategy, and that considerable intraspecific variation exists. Questions remain as to the amount of energy gain derived from the income strategy, and the consequences for pup condition and survival. |
format |
Article in Journal/Newspaper |
author |
Wheatley, KE Bradshaw, CJA Harcourt, RG Hindell, MA |
author_facet |
Wheatley, KE Bradshaw, CJA Harcourt, RG Hindell, MA |
author_sort |
Wheatley, KE |
title |
Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals |
title_short |
Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals |
title_full |
Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals |
title_fullStr |
Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals |
title_full_unstemmed |
Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals |
title_sort |
feast or famine: evidence for mixed capital-income breeding strategies in weddell seals |
publishDate |
2008 |
url |
https://eprints.utas.edu.au/3143/ https://eprints.utas.edu.au/3143/1/Oecologia.pdf https://doi.org/10.1007/s00442-007-0888-7 |
geographic |
Weddell |
geographic_facet |
Weddell |
genre |
Weddell Seal Weddell Seals |
genre_facet |
Weddell Seal Weddell Seals |
op_relation |
https://eprints.utas.edu.au/3143/1/Oecologia.pdf Wheatley, KE, Bradshaw, CJA, Harcourt, RG and Hindell, MA 2008 , 'Feast or Famine: evidence for mixed capital-income breeding strategies in Weddell seals' , Oecologia, vol. 155, no. 1 , pp. 11-20 , doi:10.1007/s00442-007-0888-7 <http://dx.doi.org/10.1007/s00442-007-0888-7>. |
op_rights |
cc_utas |
op_doi |
https://doi.org/10.1007/s00442-007-0888-7 |
container_title |
Oecologia |
container_volume |
155 |
container_issue |
1 |
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11 |
op_container_end_page |
20 |
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1766233753758203904 |