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Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum

The baculum is an enigmatic bone within the mammalian glans penis, and the driving forces behind its often bizarre shape have captivated evolutionary biologists for over a century. Hypotheses for the function of the baculum include aiding in intromission, stimulating females and assisting with prolo...

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Autores principales: Brassey, Charlotte A., Behnsen, Julia, Gardiner, James D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7657853/
https://www.ncbi.nlm.nih.gov/pubmed/33049172
http://dx.doi.org/10.1098/rspb.2020.1883
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author Brassey, Charlotte A.
Behnsen, Julia
Gardiner, James D.
author_facet Brassey, Charlotte A.
Behnsen, Julia
Gardiner, James D.
author_sort Brassey, Charlotte A.
collection PubMed
description The baculum is an enigmatic bone within the mammalian glans penis, and the driving forces behind its often bizarre shape have captivated evolutionary biologists for over a century. Hypotheses for the function of the baculum include aiding in intromission, stimulating females and assisting with prolonged mating. Previous attempts to test these hypotheses have focused on the gross size of the baculum and have failed to reach a consensus. We conducted three-dimensional imaging and apply a new method to quantify three-dimensional shape complexity in the carnivoran baculum. We show that socially monogamous species are evolving towards complex-shaped bacula, whereas group-living species are evolving towards simple bacula. Overall three-dimensional baculum shape complexity is not related to relative testes mass, but tip complexity is higher in induced ovulators and species engaging in prolonged copulation. Our study provides evidence of postcopulatory sexual selection pressures driving three-dimensional shape complexity in the carnivore baculum.
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spelling pubmed-76578532020-11-12 Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum Brassey, Charlotte A. Behnsen, Julia Gardiner, James D. Proc Biol Sci Morphology and Biomechanics The baculum is an enigmatic bone within the mammalian glans penis, and the driving forces behind its often bizarre shape have captivated evolutionary biologists for over a century. Hypotheses for the function of the baculum include aiding in intromission, stimulating females and assisting with prolonged mating. Previous attempts to test these hypotheses have focused on the gross size of the baculum and have failed to reach a consensus. We conducted three-dimensional imaging and apply a new method to quantify three-dimensional shape complexity in the carnivoran baculum. We show that socially monogamous species are evolving towards complex-shaped bacula, whereas group-living species are evolving towards simple bacula. Overall three-dimensional baculum shape complexity is not related to relative testes mass, but tip complexity is higher in induced ovulators and species engaging in prolonged copulation. Our study provides evidence of postcopulatory sexual selection pressures driving three-dimensional shape complexity in the carnivore baculum. The Royal Society 2020-10-14 2020-10-14 /pmc/articles/PMC7657853/ /pubmed/33049172 http://dx.doi.org/10.1098/rspb.2020.1883 Text en © 2020 The Authors. http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/http://creativecommons.org/licenses/by/4.0/Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
spellingShingle Morphology and Biomechanics
Brassey, Charlotte A.
Behnsen, Julia
Gardiner, James D.
Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum
title Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum
title_full Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum
title_fullStr Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum
title_full_unstemmed Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum
title_short Postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum
title_sort postcopulatory sexual selection and the evolution of shape complexity in the carnivoran baculum
topic Morphology and Biomechanics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7657853/
https://www.ncbi.nlm.nih.gov/pubmed/33049172
http://dx.doi.org/10.1098/rspb.2020.1883
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