Relationships between sperm length and speed differ among three internally and three externally fertilizing species

Simpson, Julia L. and Humphries, Stuart and Evans, Jonathan P. and Simmons, Leigh W. and Fitzpatrick, John L. (2014) Relationships between sperm length and speed differ among three internally and three externally fertilizing species. Evolution, 68 (1). pp. 92-104. ISSN 0014-3820

Documents
Relationships between sperm length and speed differ among three internally and three externally fertilizing species

Request a copy
[img] PDF
__ddat02_staffhome_jpartridge_evo12199.pdf - Whole Document
Restricted to Repository staff only

744kB
Item Type:Article
Item Status:Live Archive

Abstract

It is often assumed that longer sperm, by virtue of their increased swimming speed, have a fertilization advantage over shorter sperm when in competition to fertilize eggs. However, there is surprisingly little evidence for a positive correlation between sperm length and speed. Here we use an approach that accounts for within-male variation in sperm traits to examine the relationships between sperm length and sperm speed across a broad range of species, including three internally fertilizing species and three externally fertilizing species. Our results reveal that correlations between sperm size and speed are indeed present and possibly more common than currently thought. However, the direction of the correlations between sperm length and speed, which are more prevalent within a male's ejaculate than among males, were influenced by fertilization mode in contrasting and unexpected ways. Broadly, the patterns revealed that in externally fertilizing species sperm with longer flagellum and shorter heads relative to their flagellum swam faster, whereas in internally fertilizing species sperm with shorter flagellum and longer heads relative to their flagellum swam faster. We discuss these results in light of sperm competition theory and contrast the intraspecific patterns observed in this study with macroevolutionary patterns of sperm evolution reported elsewhere. © 2013 The Society for the Study of Evolution.

Keywords:correlation, crypsis, egg, evolutionary biology, fertilization (reproduction), sperm competition, adaptation, animal, article, cryptic female choice, cytology, fertilization, genetics, human, male, molecular evolution, sperm competition, sperm length components, spermatozoon, spermatozoon motility, Cryptic female choice, sperm length components, Adaptation, Physiological, Animals, Evolution, Molecular, Humans, Sperm Motility, Spermatozoa, NotOAChecked
Subjects:C Biological Sciences > C182 Evolution
C Biological Sciences > C130 Cell Biology
Divisions:College of Science > School of Life Sciences
Related URLs:
ID Code:15247
Deposited On:03 Oct 2014 10:49

Repository Staff Only: item control page