Seal mothers expend more on offspring under favourable conditions and less when resources are limited
In mammals, maternal expenditure on offspring is a complex mix of several factors including the species’ mating system, offspring sex and the condition and age of the mother. While theory suggests that in polygynous species mothers should wean larger male offspring than females when resources and ma...
Published in: | Journal of Animal Ecology |
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Online Access: | https://researchers.mq.edu.au/en/publications/38ac670c-0ea1-4fc2-af79-34c7b336489a https://doi.org/10.1111/1365-2656.12611 http://www.scopus.com/inward/record.url?scp=85010748536&partnerID=8YFLogxK |
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ftmacquarieunicr:oai:https://researchers.mq.edu.au:publications/38ac670c-0ea1-4fc2-af79-34c7b336489a 2024-10-13T14:02:49+00:00 Seal mothers expend more on offspring under favourable conditions and less when resources are limited McMahon, Clive R. Harcourt, Robert G. Burton, Harry R. Daniel, Owen Hindell, Mark A. 2017-03-01 https://researchers.mq.edu.au/en/publications/38ac670c-0ea1-4fc2-af79-34c7b336489a https://doi.org/10.1111/1365-2656.12611 http://www.scopus.com/inward/record.url?scp=85010748536&partnerID=8YFLogxK eng eng info:eu-repo/semantics/closedAccess McMahon , C R , Harcourt , R G , Burton , H R , Daniel , O & Hindell , M A 2017 , ' Seal mothers expend more on offspring under favourable conditions and less when resources are limited ' , Journal of Animal Ecology , vol. 86 , no. 2 , pp. 359-370 . https://doi.org/10.1111/1365-2656.12611 Antarctica Integrated Marine Observing System life history Mirounga leonina survival article 2017 ftmacquarieunicr https://doi.org/10.1111/1365-2656.12611 2024-10-03T00:23:11Z In mammals, maternal expenditure on offspring is a complex mix of several factors including the species’ mating system, offspring sex and the condition and age of the mother. While theory suggests that in polygynous species mothers should wean larger male offspring than females when resources and maternal conditions allow, the evidence for this remains equivocal. Southern elephant seals are highly dimorphic, polygynous capital breeders existing in an environment with highly variable resources and should therefore provide clear evidence to support the theoretical expectations of differential maternal expenditure in male and female pups. We quantified maternal size (mass and length) and pup size at birth and weaning for 342 elephant seal mothers at Macquarie Island. The study was conducted over 11 years of contrasting sea-ice and Southern Annular Mode values, both indices of maternal prey resources. Overall, large females weaned male pups that weighed 17 kg (15·5%) more than female pups. Maternal condition varied by as much as 59 kg among years, and was positively related to Southern Annular Mode, and negatively to maximum sea-ice extent. Smaller mothers weaned relatively larger male pups under favourable conditions, this effect was less apparent for larger mothers. We developed a simple model linking environmental variation to maternal masses post-partum, followed by maternal masses post-partum to weaning masses and then weaning masses to pup survival and demonstrated that environmental conditions affected predicted survival so that the pups of small mothers had an estimated 7% increase in first year survival in ‘good’ vs. ‘bad’ years compared to 1% for female pups of large mothers. Co-occurrence of environmental quality and conservative reproductive tactics suggests that mothers retain substantial plasticity in maternal care, enhancing their lifetime reproductive success by adjusting reproductive expenditure relative to both prevailing environmental conditions and their own capabilities. Article in Journal/Newspaper Antarc* Antarctica Elephant Seal Elephant Seals Macquarie Island Mirounga leonina Sea ice Southern Elephant Seals Macquarie University Research Portal Journal of Animal Ecology 86 2 359 370 |
institution |
Open Polar |
collection |
Macquarie University Research Portal |
op_collection_id |
ftmacquarieunicr |
language |
English |
topic |
Antarctica Integrated Marine Observing System life history Mirounga leonina survival |
spellingShingle |
Antarctica Integrated Marine Observing System life history Mirounga leonina survival McMahon, Clive R. Harcourt, Robert G. Burton, Harry R. Daniel, Owen Hindell, Mark A. Seal mothers expend more on offspring under favourable conditions and less when resources are limited |
topic_facet |
Antarctica Integrated Marine Observing System life history Mirounga leonina survival |
description |
In mammals, maternal expenditure on offspring is a complex mix of several factors including the species’ mating system, offspring sex and the condition and age of the mother. While theory suggests that in polygynous species mothers should wean larger male offspring than females when resources and maternal conditions allow, the evidence for this remains equivocal. Southern elephant seals are highly dimorphic, polygynous capital breeders existing in an environment with highly variable resources and should therefore provide clear evidence to support the theoretical expectations of differential maternal expenditure in male and female pups. We quantified maternal size (mass and length) and pup size at birth and weaning for 342 elephant seal mothers at Macquarie Island. The study was conducted over 11 years of contrasting sea-ice and Southern Annular Mode values, both indices of maternal prey resources. Overall, large females weaned male pups that weighed 17 kg (15·5%) more than female pups. Maternal condition varied by as much as 59 kg among years, and was positively related to Southern Annular Mode, and negatively to maximum sea-ice extent. Smaller mothers weaned relatively larger male pups under favourable conditions, this effect was less apparent for larger mothers. We developed a simple model linking environmental variation to maternal masses post-partum, followed by maternal masses post-partum to weaning masses and then weaning masses to pup survival and demonstrated that environmental conditions affected predicted survival so that the pups of small mothers had an estimated 7% increase in first year survival in ‘good’ vs. ‘bad’ years compared to 1% for female pups of large mothers. Co-occurrence of environmental quality and conservative reproductive tactics suggests that mothers retain substantial plasticity in maternal care, enhancing their lifetime reproductive success by adjusting reproductive expenditure relative to both prevailing environmental conditions and their own capabilities. |
format |
Article in Journal/Newspaper |
author |
McMahon, Clive R. Harcourt, Robert G. Burton, Harry R. Daniel, Owen Hindell, Mark A. |
author_facet |
McMahon, Clive R. Harcourt, Robert G. Burton, Harry R. Daniel, Owen Hindell, Mark A. |
author_sort |
McMahon, Clive R. |
title |
Seal mothers expend more on offspring under favourable conditions and less when resources are limited |
title_short |
Seal mothers expend more on offspring under favourable conditions and less when resources are limited |
title_full |
Seal mothers expend more on offspring under favourable conditions and less when resources are limited |
title_fullStr |
Seal mothers expend more on offspring under favourable conditions and less when resources are limited |
title_full_unstemmed |
Seal mothers expend more on offspring under favourable conditions and less when resources are limited |
title_sort |
seal mothers expend more on offspring under favourable conditions and less when resources are limited |
publishDate |
2017 |
url |
https://researchers.mq.edu.au/en/publications/38ac670c-0ea1-4fc2-af79-34c7b336489a https://doi.org/10.1111/1365-2656.12611 http://www.scopus.com/inward/record.url?scp=85010748536&partnerID=8YFLogxK |
genre |
Antarc* Antarctica Elephant Seal Elephant Seals Macquarie Island Mirounga leonina Sea ice Southern Elephant Seals |
genre_facet |
Antarc* Antarctica Elephant Seal Elephant Seals Macquarie Island Mirounga leonina Sea ice Southern Elephant Seals |
op_source |
McMahon , C R , Harcourt , R G , Burton , H R , Daniel , O & Hindell , M A 2017 , ' Seal mothers expend more on offspring under favourable conditions and less when resources are limited ' , Journal of Animal Ecology , vol. 86 , no. 2 , pp. 359-370 . https://doi.org/10.1111/1365-2656.12611 |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1111/1365-2656.12611 |
container_title |
Journal of Animal Ecology |
container_volume |
86 |
container_issue |
2 |
container_start_page |
359 |
op_container_end_page |
370 |
_version_ |
1812819274030383104 |