scholarly journals Intramale variation in sperm size: functional significance in a polygynous mammal

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1478 ◽  
Author(s):  
José Luis Ros-Santaella ◽  
Eliana Pintus ◽  
José Julián Garde
Keyword(s):  
Sexual Selection ◽  
Red Deer ◽  
Sperm Morphology ◽  
Size Variation ◽  
Sperm Velocity ◽  
Selective Force ◽  
Animal Kingdom ◽  
Normal Sperm ◽  
Selection Mechanisms ◽  
Sperm Size

Studies concerning the relationships between sperm size and velocity at the intraspecific level are quite limited and often yielded contradictory results across the animal kingdom. Intramale variation in sperm size may represent a meaningful factor to predict sperm velocity, due to its relationship with the level of sperm competition among related taxa. Because sperm phenotype is under post-copulatory sexual selection, we hypothesized that a reduced intramale variation in sperm size is associated with sperm competitiveness in red deer. Our results show that low variation in sperm size is strongly related to high sperm velocity and normal sperm morphology, which in turn are good predictors of male fertility in this species. Furthermore, it is well known that the red deer show high variability in testicular mass but there is limited knowledge concerning the significance of this phenomenon at intraspecific level, even though it may reveal interesting processes of sexual selection. Thereby, as a preliminary result, we found that absolute testes mass is negatively associated with intramale variation in sperm size. Our findings suggest that sperm size variation in red deer is under a strong selective force leading to increase sperm function efficiency, and reveal new insights into sexual selection mechanisms.

Sperm morphology of the Rattini – are the interspecific differences due to variation in intensity of intermale sperm competition?

2018 ◽  
Vol 30 (11) ◽  
pp. 1434 ◽  
Author(s):  
Tessa Pahl ◽  
Hanna J. McLennan ◽  
Yun Wang ◽  
Anang S. Achmadi ◽  
Kevin C. Rowe ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Sperm Morphology ◽  
Tail Length ◽  
Sperm Head ◽  
Apical Hook ◽  
Interspecific Differences ◽  
Murine Rodent ◽  
Murine Rodents ◽  
Sperm Size

It is widely accepted that in mammals a causal relationship exists between postcopulatory sexual selection and relative testes mass of the species concerned, but how much it determines sperm size and shape is debatable. Here we detailed for the largest murine rodent tribe, the Rattini, the interspecific differences in relative testes mass and sperm form. We found that residual testes mass correlates with sperm head apical hook length as well as its angle, together with tail length, and that within several lineages a few species have evolved highly divergent sperm morphology with a reduced or absent apical hook and shorter tail. Although most species have a relative testes mass of 1–4%, these derived sperm traits invariably co-occur in species with much smaller relative testes mass. We therefore suggest that high levels of intermale sperm competition maintain a sperm head with a long apical hook and long tail, whereas low levels of intermale sperm competition generally result in divergent sperm heads with a short or non-existent apical hook and shorter tail. We thus conclude that sexual selection is a major selective force in driving sperm head form and tail length in this large tribe of murine rodents.

scholarly journals Sperm midpiece length predicts sperm swimming velocity in house mice

2010 ◽  
Vol 6 (4) ◽  
pp. 513-516 ◽  
Author(s):  
Renée C. Firman ◽  
Leigh W. Simmons
Keyword(s):  
Sperm Competition ◽  
Sperm Morphology ◽  
House Mice ◽  
Swimming Velocity ◽  
Sperm Velocity ◽  
Sperm Midpiece ◽  
Sperm Competition Risk ◽  
Sperm Size ◽  
The Relationship

Evolutionary biologists have argued that there should be a positive relationship between sperm size and sperm velocity, and that these traits influence a male's sperm competitiveness. However, comparative analyses investigating the evolutionary associations between sperm competition risk and sperm morphology have reported inconsistent patterns of association, and in vitro sperm competition experiments have further confused the issue; in some species, males with longer sperm achieve more competitive fertilization, while in other species males with shorter sperm have greater sperm competitiveness. Few investigations have attempted to address this problem. Here, we investigated the relationship between sperm morphology and sperm velocity in house mice ( Mus domesticus ). We conducted in vitro sperm velocity assays on males from established selection lines, and found that sperm midpiece size was the only phenotypic predictor of sperm swimming velocity.

scholarly journals Selection on sperm morphology under relaxed sperm competition in a wild passerine bird

2008 ◽  
Vol 5 (1) ◽  
pp. 58-61 ◽  
Author(s):  
Sara Calhim ◽  
Helene M Lampe ◽  
Tore Slagsvold ◽  
Tim R Birkhead
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Sperm Morphology ◽  
Reproductive Traits ◽  
Female Preference ◽  
Passerine Bird ◽  
High Heritability ◽  
Individual Consistency ◽  
Sperm Size

Theories regarding the role of sexual selection on the evolution of sperm traits are based on an association between pre-copulatory (e.g. female preference) and post-copulatory (e.g. ejaculate quality) male reproductive traits. In tests of these hypotheses, sperm morphology has rarely been used, despite its high heritability and intra-individual consistency. We found evidence of selection for longer sperm through positive phenotypic associations between sperm size and the two major female preference traits in the pied flycatcher, Ficedula hypoleuca . Our results support the sexually selected sperm hypothesis in a species under low sperm competition and demonstrate that natural and pre-copulatory sexual selection forces should not be overlooked in studies of intraspecific sperm morphology evolution.

scholarly journals Assessment of Sperm Quality - A Light Microscope Study

2021 ◽  
Vol 10 (19) ◽  
pp. 1417-1421
Author(s):  
Jyothi A. Raj ◽  
Heera Sankar ◽  
Sagarika Mahapatra ◽  
Ashima Binny
Keyword(s):  
Light Microscope ◽  
Sperm Morphology ◽  
Clinical Laboratory ◽  
Sperm Quality ◽  
Semen Analysis ◽  
Complete Evaluation ◽  
Normal Sperm ◽  
Middle Piece ◽  
Sperm Counts ◽  
Work Up

BACKGROUND Semen analysis is an integral part of work up for infertility in men, with sperm morphology being an important qualitative parameter. Qualitative defects can affect any part of the sperm and are classified as defects in the head, middle piece, and tail, based on morphology. The focus of the study was to assess qualitative defects in sperms by light microscopy, in semen with normal sperm counts. METHODS This study is hospital based, descriptive, retrospective study. Of the semen samples received in the clinical laboratory, fifty with normal sperm counts were included in the study and processed according to standard protocol. For evaluation of qualitative defects by sperm morphology, smears were fixed in ethanol, stained with Papanicolaou stain [PAP], and assessed under light microscope. RESULTS The 50 semen samples included in the study had sperm counts ranging from 15 to 80 million / ml. Thirty samples had less than 10 % abnormal forms, fourteen samples had 11 - 20 % abnormal forms, five samples had 21 - 30 % abnormal forms and one sample had 40 % abnormal sperms. Qualitative defects were classified as morphological abnormalities in head, neck, and tail. Of the fifty cases, most defects were found in the head, followed by those in the neck and tail. Common defects noted were double head (44 %), abnormal sized heads, and bent neck (48 %). Coiling was a common defect noted in the tail (10 %). Most sperms showed a combination of defects. CONCLUSIONS Qualitative defects in sperm morphology are often seen in samples with normal sperm counts. Assessment of microscopic characteristics of human spermatozoa is as important as count and motility in the complete evaluation and work-up of semen samples in cases of infertility. KEY WORDS Semen, Sperm, Quality, Microscopy, Morphology

scholarly journals Male Fertility in Natural Populations of Red Deer Is Determined by Sperm Velocity and the Proportion of Normal Spermatozoa1

2005 ◽  
Vol 72 (4) ◽  
pp. 822-829 ◽  
Author(s):  
Aurelio F. Malo ◽  
J. Julián Garde ◽  
Ana J. Soler ◽  
Andrés J. García ◽  
Montserrat Gomendio ◽  
...  
Keyword(s):  
Male Fertility ◽  
Red Deer ◽  
Natural Populations ◽  
Sperm Velocity

scholarly journals Fertilization competence and sperm size variation in sperm-heteromorphic insects

2005 ◽  
Vol 19 (1) ◽  
pp. 45-54 ◽  
Author(s):  
G. Bernasconi ◽  
B. Hellriegel
Keyword(s):  
Size Variation ◽  
Sperm Size

scholarly journals Sexual selection after gamete release in broadcast spawning invertebrates

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200069 ◽  
Author(s):  
Jonathan P. Evans ◽  
Rowan A. Lymbery
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Sperm Competition ◽  
Sexual Conflict ◽  
Gamete Release ◽  
Theme Issue ◽  
Animal Kingdom ◽  
External Fertilization ◽  
Broadcast Spawning ◽  
Males And Females

Broadcast spawning invertebrates offer highly tractable models for evaluating sperm competition, gamete-level mate choice and sexual conflict. By displaying the ancestral mating strategy of external fertilization, where sexual selection is constrained to act after gamete release, broadcast spawners also offer potential evolutionary insights into the cascade of events that led to sexual reproduction in more ‘derived’ groups (including humans). Moreover, the dynamic reproductive conditions faced by these animals mean that the strength and direction of sexual selection on both males and females can vary considerably. These attributes make broadcast spawning invertebrate systems uniquely suited to testing, extending, and sometimes challenging classic and contemporary ideas in sperm competition, many of which were first captured in Parker's seminal papers on the topic. Here, we provide a synthesis outlining progress in these fields, and highlight the burgeoning potential for broadcast spawners to provide both evolutionary and mechanistic understanding into gamete-level sexual selection more broadly across the animal kingdom. This article is part of the theme issue ‘Fifty years of sperm competition’.

Normal sperm morphology and chromatin packaging: comparison between aniline blue and chromomycin A3 staining

Andrologia ◽  
1999 ◽  
Vol 31 (6) ◽  
pp. 361-366 ◽  
Author(s):  
D. R. Franken ◽  
C. J. Franken ◽  
H. de la Guerre ◽  
A. de Villiers
Keyword(s):  
Sperm Morphology ◽  
Aniline Blue ◽  
Chromomycin A3 ◽  
Normal Sperm

scholarly journals R-027. Normal sperm morphology predicts the outcome of IUI

1997 ◽  
Vol 12 (Suppl_2) ◽  
pp. 248-249
Author(s):  
C. Keck ◽  
C. Gerber-Schafer ◽  
J. Neulen ◽  
N. Breckwoldt
Keyword(s):  
Sperm Morphology ◽  
Normal Sperm
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