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Postreproductive killer whale grandmothers improve the survival of their grandoffspring

Understanding why females of some mammalian species cease ovulation prior to the end of life is a long-standing interdisciplinary and evolutionary challenge. In humans and some species of toothed whales, females can live for decades after stopping reproduction. This unusual life history trait is tho...

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Autores principales: Nattrass, Stuart, Croft, Darren P., Ellis, Samuel, Cant, Michael A., Weiss, Michael N., Wright, Brianna M., Stredulinsky, Eva, Doniol-Valcroze, Thomas, Ford, John K. B., Balcomb, Kenneth C., Franks, Daniel W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936675/
https://www.ncbi.nlm.nih.gov/pubmed/31818941
http://dx.doi.org/10.1073/pnas.1903844116
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author Nattrass, Stuart
Croft, Darren P.
Ellis, Samuel
Cant, Michael A.
Weiss, Michael N.
Wright, Brianna M.
Stredulinsky, Eva
Doniol-Valcroze, Thomas
Ford, John K. B.
Balcomb, Kenneth C.
Franks, Daniel W.
author_facet Nattrass, Stuart
Croft, Darren P.
Ellis, Samuel
Cant, Michael A.
Weiss, Michael N.
Wright, Brianna M.
Stredulinsky, Eva
Doniol-Valcroze, Thomas
Ford, John K. B.
Balcomb, Kenneth C.
Franks, Daniel W.
author_sort Nattrass, Stuart
collection PubMed
description Understanding why females of some mammalian species cease ovulation prior to the end of life is a long-standing interdisciplinary and evolutionary challenge. In humans and some species of toothed whales, females can live for decades after stopping reproduction. This unusual life history trait is thought to have evolved, in part, due to the inclusive fitness benefits that postreproductive females gain by helping kin. In humans, grandmothers gain inclusive fitness benefits by increasing their number of surviving grandoffspring, referred to as the grandmother effect. Among toothed whales, the grandmother effect has not been rigorously tested. Here, we test for the grandmother effect in killer whales, by quantifying grandoffspring survival with living or recently deceased reproductive and postreproductive grandmothers, and show that postreproductive grandmothers provide significant survival benefits to their grandoffspring above that provided by reproductive grandmothers. This provides evidence of the grandmother effect in a nonhuman menopausal species. By stopping reproduction, grandmothers avoid reproductive conflict with their daughters, and offer increased benefits to their grandoffspring. The benefits postreproductive grandmothers provide to their grandoffspring are shown to be most important in difficult times where the salmon abundance is low to moderate. The postreproductive grandmother effect we report, together with the known costs of late-life reproduction in killer whales, can help explain the long postreproductive life spans of resident killer whales.
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spelling pubmed-69366752019-12-31 Postreproductive killer whale grandmothers improve the survival of their grandoffspring Nattrass, Stuart Croft, Darren P. Ellis, Samuel Cant, Michael A. Weiss, Michael N. Wright, Brianna M. Stredulinsky, Eva Doniol-Valcroze, Thomas Ford, John K. B. Balcomb, Kenneth C. Franks, Daniel W. Proc Natl Acad Sci U S A Biological Sciences Understanding why females of some mammalian species cease ovulation prior to the end of life is a long-standing interdisciplinary and evolutionary challenge. In humans and some species of toothed whales, females can live for decades after stopping reproduction. This unusual life history trait is thought to have evolved, in part, due to the inclusive fitness benefits that postreproductive females gain by helping kin. In humans, grandmothers gain inclusive fitness benefits by increasing their number of surviving grandoffspring, referred to as the grandmother effect. Among toothed whales, the grandmother effect has not been rigorously tested. Here, we test for the grandmother effect in killer whales, by quantifying grandoffspring survival with living or recently deceased reproductive and postreproductive grandmothers, and show that postreproductive grandmothers provide significant survival benefits to their grandoffspring above that provided by reproductive grandmothers. This provides evidence of the grandmother effect in a nonhuman menopausal species. By stopping reproduction, grandmothers avoid reproductive conflict with their daughters, and offer increased benefits to their grandoffspring. The benefits postreproductive grandmothers provide to their grandoffspring are shown to be most important in difficult times where the salmon abundance is low to moderate. The postreproductive grandmother effect we report, together with the known costs of late-life reproduction in killer whales, can help explain the long postreproductive life spans of resident killer whales. National Academy of Sciences 2019-12-26 2019-12-09 /pmc/articles/PMC6936675/ /pubmed/31818941 http://dx.doi.org/10.1073/pnas.1903844116 Text en Copyright © 2019 the Author(s). Published by PNAS. http://creativecommons.org/licenses/by/4.0/ https://creativecommons.org/licenses/by/4.0/This open access article is distributed under Creative Commons Attribution License 4.0 (CC BY) (http://creativecommons.org/licenses/by/4.0/) .
spellingShingle Biological Sciences
Nattrass, Stuart
Croft, Darren P.
Ellis, Samuel
Cant, Michael A.
Weiss, Michael N.
Wright, Brianna M.
Stredulinsky, Eva
Doniol-Valcroze, Thomas
Ford, John K. B.
Balcomb, Kenneth C.
Franks, Daniel W.
Postreproductive killer whale grandmothers improve the survival of their grandoffspring
title Postreproductive killer whale grandmothers improve the survival of their grandoffspring
title_full Postreproductive killer whale grandmothers improve the survival of their grandoffspring
title_fullStr Postreproductive killer whale grandmothers improve the survival of their grandoffspring
title_full_unstemmed Postreproductive killer whale grandmothers improve the survival of their grandoffspring
title_short Postreproductive killer whale grandmothers improve the survival of their grandoffspring
title_sort postreproductive killer whale grandmothers improve the survival of their grandoffspring
topic Biological Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936675/
https://www.ncbi.nlm.nih.gov/pubmed/31818941
http://dx.doi.org/10.1073/pnas.1903844116
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