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Sperm competition: linking form to function

BACKGROUND: Using information from physics, biomechanics and evolutionary biology, we explore the implications of physical constraints on sperm performance, and review empirical evidence for links between sperm length and sperm competition (where two or more males compete to fertilise a female'...

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Detalles Bibliográficos
Autores principales: Humphries, Stuart, Evans, Jonathan P, Simmons, Leigh W
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2632676/
https://www.ncbi.nlm.nih.gov/pubmed/19032741
http://dx.doi.org/10.1186/1471-2148-8-319
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author Humphries, Stuart
Evans, Jonathan P
Simmons, Leigh W
author_facet Humphries, Stuart
Evans, Jonathan P
Simmons, Leigh W
author_sort Humphries, Stuart
collection PubMed
description BACKGROUND: Using information from physics, biomechanics and evolutionary biology, we explore the implications of physical constraints on sperm performance, and review empirical evidence for links between sperm length and sperm competition (where two or more males compete to fertilise a female's eggs). A common theme in the literature on sperm competition is that selection for increased sperm performance in polyandrous species will favour the evolution of longer, and therefore faster swimming, sperm. This argument is based on the common assumption that sperm swimming velocity is directly related to sperm length, due to the increased thrust produced by longer flagella. RESULTS: We critically evaluate the evidence for links between sperm morphology and swimming speed, and draw on cross-disciplinary studies to show that the assumption that velocity is directly related to sperm length will rarely be satisfied in the microscopic world in which sperm operate. CONCLUSION: We show that increased sperm length is unlikely to be driven by selection for increased swimming speed, and that the relative lengths of a sperm's constituent parts, rather than their absolute lengths, are likely to be the target of selection. All else being equal, we suggest that a simple measure of the ratio of head to tail length should be used to assess the possible link between morphology and speed. However, this is most likely to be the case for external fertilizers in which females have relatively limited opportunity to influence a sperm's motility.
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spelling pubmed-26326762009-01-30 Sperm competition: linking form to function Humphries, Stuart Evans, Jonathan P Simmons, Leigh W BMC Evol Biol Research Article BACKGROUND: Using information from physics, biomechanics and evolutionary biology, we explore the implications of physical constraints on sperm performance, and review empirical evidence for links between sperm length and sperm competition (where two or more males compete to fertilise a female's eggs). A common theme in the literature on sperm competition is that selection for increased sperm performance in polyandrous species will favour the evolution of longer, and therefore faster swimming, sperm. This argument is based on the common assumption that sperm swimming velocity is directly related to sperm length, due to the increased thrust produced by longer flagella. RESULTS: We critically evaluate the evidence for links between sperm morphology and swimming speed, and draw on cross-disciplinary studies to show that the assumption that velocity is directly related to sperm length will rarely be satisfied in the microscopic world in which sperm operate. CONCLUSION: We show that increased sperm length is unlikely to be driven by selection for increased swimming speed, and that the relative lengths of a sperm's constituent parts, rather than their absolute lengths, are likely to be the target of selection. All else being equal, we suggest that a simple measure of the ratio of head to tail length should be used to assess the possible link between morphology and speed. However, this is most likely to be the case for external fertilizers in which females have relatively limited opportunity to influence a sperm's motility. BioMed Central 2008-11-25 /pmc/articles/PMC2632676/ /pubmed/19032741 http://dx.doi.org/10.1186/1471-2148-8-319 Text en Copyright ©2008 Humphries et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Humphries, Stuart
Evans, Jonathan P
Simmons, Leigh W
Sperm competition: linking form to function
title Sperm competition: linking form to function
title_full Sperm competition: linking form to function
title_fullStr Sperm competition: linking form to function
title_full_unstemmed Sperm competition: linking form to function
title_short Sperm competition: linking form to function
title_sort sperm competition: linking form to function
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2632676/
https://www.ncbi.nlm.nih.gov/pubmed/19032741
http://dx.doi.org/10.1186/1471-2148-8-319
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