scholarly journals Delineating the roles of males and females in sperm competition

2013 ◽  
Vol 280 (1772) ◽  
pp. 20132047 ◽  
Author(s):  
Jonathan P. Evans ◽  
Patrice Rosengrave ◽  
Clelia Gasparini ◽  
Neil J. Gemmell
Keyword(s):  
Sperm Competition ◽  
Chinook Salmon ◽  
Competitive Ability ◽  
Oncorhynchus Tshawytscha ◽  
Fertilization Success ◽  
Interactive Effects ◽  
Swimming Velocity ◽  
Ovarian Fluid ◽  
Males And Females ◽  
Paternity Success

Disentangling the relative roles of males, females and their interactive effects on competitive fertilization success remains a challenge in sperm competition. In this study, we apply a novel experimental framework to an ideally suited externally fertilizing model system in order to delineate these roles. We focus on the chinook salmon, Oncorhynchus tshawytscha , a species in which ovarian fluid (OF) has been implicated as a potential arbiter of cryptic female choice for genetically compatible mates. We evaluated this predicted sexually selected function of OF using a series of factorial competitive fertilization trials. Our design involved a series of 10 factorial crosses, each involving two ‘focal’ rival males whose sperm competed against those from a single ‘standardized’ (non-focal) rival for a genetically uniform set of eggs in the presence of OF from two focal females. This design enabled us to attribute variation in competitive fertilization success among focal males, females (OF) and their interacting effects, while controlling for variation attributable to differences in the sperm competitive ability of rival males, and male-by-female genotypic interactions. Using this experimental framework, we found that variation in sperm competitiveness could be attributed exclusively to differences in the sperm competitive ability of focal males, a conclusion supported by subsequent analyses revealing that variation in sperm swimming velocity predicts paternity success. Together, these findings provide evidence that variation in paternity success can be attributed to intrinsic differences in the sperm competitive ability of rival males, and reveal that sperm swimming velocity is a key target of sexual selection.

scholarly journals Male–female relatedness at specific SNP-linkage groups influences cryptic female choice in Chinook salmon ( Oncorhynchus tshawytscha )

2017 ◽  
Vol 284 (1859) ◽  
pp. 20170853 ◽  
Author(s):  
Cornelia Geßner ◽  
Sheri L. Johnson ◽  
Paul Fisher ◽  
Shannon Clarke ◽  
Kim Rutherford ◽  
...  
Keyword(s):  
Female Choice ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Fertilization Success ◽  
Cryptic Female Choice ◽  
Linkage Groups ◽  
Sperm Velocity ◽  
Ovarian Fluid ◽  
The Impact

In a range of taxa, the relatedness between mates influences both pre- and post-mating processes of sexual selection. However, relatively little is known about the genetic loci facilitating such a bias, with the exception of the major histocompatibility complex. Here, we performed tightly controlled replicated in vitro fertilization trials to explore the impact of relatedness on two possible mechanisms of cryptic female choice (CFC) in Chinook salmon ( Oncorhynchus tshawytscha ). We tested (i) whether relatedness of mates, assessed using 682 single nucleotide polymorphisms (SNPs) on 29 SNP-linkage groups (LGs), biases a male's sperm velocity in ovarian fluid (a parameter previously shown to predict male fertilization success), and (ii) whether relatedness of mates governs fertilization success via other mechanisms, probably via sperm–egg interactions. We found that relatedness on three LGs explained the variation in sperm velocity, and relatedness on two LGs explained fertilization success, which might indicate the presence of genes important in sperm–ovarian fluid and sperm–egg interactions in these genomic regions. Mapping of the SNPs on these LGs to the rainbow trout genome revealed two genes that affect fertility in humans and represent candidate genes for further studies. Our results thereby provide a novel contribution to the understanding of the mechanism of CFC.

Sperm traits in Chinook salmon depend upon activation medium: implications for studies of sperm competition in fishes

2009 ◽  
Vol 87 (10) ◽  
pp. 920-927 ◽  
Author(s):  
P. Rosengrave ◽  
R. Montgomerie ◽  
V. J. Metcalf ◽  
K. McBride ◽  
N. J. Gemmell
Keyword(s):  
Sperm Competition ◽  
Fresh Water ◽  
Swimming Speed ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Salt Water ◽  
Computer Assisted ◽  
Ovarian Fluid ◽  
Sperm Swimming Speed ◽  
Sperm Traits

Sperm traits of externally fertilizing fish species are typically measured in fresh (or salt) water, even though the spawning environment of their ova contains ovarian fluid. In this study, we measured sperm traits of Chinook salmon ( Oncorhynchus tshawytscha (Walbaum in Artedi, 1792)) in both fresh water and dilute ovarian fluid at 10 and 20 s postactivation, using a computer-assisted sperm analysis system. Spermatozoa swam faster, and had both higher percent motility and a straighter path trajectory for a longer period of forward motility when activated in ovarian fluid compared with activation in fresh water. Comparing sperm activity of 10 males in water versus ovarian fluid, we found a weak but significant correlation for sperm swimming speed at 10 s postactivation (r = 0.34, p = 0.01), but not for any other sperm traits measured. Most important, across males, mean sperm swimming speed in water accounted for <10% of the observed variation in mean sperm swimming speed in ovarian fluid. Thus, we argue that sperm traits measured in fresh water are not particularly relevant to those same traits during normal spawning in this species. We suggest that sperm performance measured in fresh water should be used with caution when comparing the potential for individual males to fertilize ova, especially in studies of sperm competition in externally fertilizing species.

Oxygen and carbon dioxide transport during sustained exercise in diploid and triploid chinook salmon (Oncorhynchus tshawytscha)

2004 ◽  
Vol 61 (9) ◽  
pp. 1797-1805 ◽  
Author(s):  
Nicholas J Bernier ◽  
Colin J Brauner ◽  
John W Heath ◽  
David J Randall
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Respiratory Physiology ◽  
Swimming Velocity ◽  
Acid Base Balance ◽  
Carbon Dioxide Transport ◽  
Partial Pressures ◽  
Consumption Rates ◽  
Base Balance ◽  
Triploid Fish

To better understand the respiratory physiology of triploid fish, we conducted an analysis of O2 and CO2 transport in diploid and triploid chinook salmon (Oncorhynchus tshawytscha) swimming at 0.4 body lengths (BL)·s–1, at 2.0 BL·s–1, and at the critical swimming velocity (Ucrit). While O2 consumption rates (MO2), MO2 max, and Ucrit did not differ between ploidies, triploids had a smaller increase in MO2 over the course of the swimming trial and lower arterial O2 content (CaO2) values than diploids. Relative to diploids, triploids swimming at Ucrit had a reduced Hb–O2 saturation, lower red blood cell (RBC) pH, but similar O2 partial pressures (PaO2) and methemoglobin values. Overall, triploids and diploids did not differ in CaCO2, PaCO2, arterial pH, or lactate at any of the swimming speeds. Taken together, triploidy does not appear to impair CO2 transport or acid–base balance during sustained exercise in chinook salmon. In contrast, our results show that triploids have a smaller O2 carrying capacity than diploids. While triploids may be able to compensate for their reduced aerobic capacity under the current exercise regime, we suggest that the effects of triploidy on O2 transport may contribute to the inferior performance of triploid salmon when reared under suboptimal conditions.

scholarly journals Turbidity of Landlocked Fall Chinook Salmon Ovarian Fluid in Relation to Egg Survival

2013 ◽  
Vol 6 (1) ◽  
pp. 75-77 ◽  
Author(s):  
Patrick A. Nero ◽  
Michael E. Barnes ◽  
Matthew M. Wipf
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Poor Survival ◽  
Ovarian Fluid ◽  
Egg Survival ◽  
Egg Development ◽  
Stage Of Development ◽  
Potential Indicator

This study evaluated the use of ovarian fluid turbidity as a potential indicator of landlocked fall Chinook Salmon Oncorhynchus tshawytscha egg survival. A total of 21 females were spawned, with nine of the spawns containing between one and ten broken eggs per spawn. Ovarian fluid turbidity ranged from 55.1 to 159 nephelometric turbidity units (NTU), and egg survival to the eyed-stage of egg development ranged from 0 to 68%. There was no significant correlation between ovarian fluid turbidity and egg survival. Mean survival of eggs from the spawns containing broken eggs was 12.3%, which was significantly lower than the 32.9% mean survival from spawns without broken eggs. These results indicate ovarian fluid turbidity cannot be used to predict egg survival in spawns of landlocked fall Chinook Salmon, but the presence of even a small number of broken eggs may be indicative of poor survival to the eyed-egg stage of development.

scholarly journals Long sperm fertilize more eggs in a bird

2015 ◽  
Vol 282 (1799) ◽  
pp. 20141897 ◽  
Author(s):  
Clair Bennison ◽  
Nicola Hemmings ◽  
Jon Slate ◽  
Tim Birkhead
Keyword(s):  
Sperm Competition ◽  
Reproductive Traits ◽  
Fertilization Success ◽  
Swimming Velocity ◽  
Sperm Length ◽  
Complex Interactions ◽  
Female Reproductive Traits ◽  
Sperm Size ◽  
The Relationship ◽  
Main Factor

Sperm competition, in which the ejaculates of multiple males compete to fertilize a female's ova, results in strong selection on sperm traits. Although sperm size and swimming velocity are known to independently affect fertilization success in certain species, exploring the relationship between sperm length, swimming velocity and fertilization success still remains a challenge. Here, we use the zebra finch ( Taeniopygia guttata ), where sperm size influences sperm swimming velocity, to determine the effect of sperm total length on fertilization success. Sperm competition experiments, in which pairs of males whose sperm differed only in length and swimming speed, revealed that males producing long sperm were more successful in terms of (i) the number of sperm reaching the ova and (ii) fertilizing those ova. Our results reveal that although sperm length is the main factor determining the outcome of sperm competition, complex interactions between male and female reproductive traits may also be important. The mechanisms underlying these interactions are poorly understood, but we suggest that differences in sperm storage and utilization by females may contribute to the outcome of sperm competition.

scholarly journals THE EFFECT OF GRADED METHAEMOGLOBIN LEVELS ON THE SWIMMING PERFORMANCE OF CHINOOK SALMON (ONCORHYNCHUS TSHAWYTSCHA)

1993 ◽  
Vol 185 (1) ◽  
pp. 121-135 ◽  
Author(s):  
C. J. Brauner ◽  
A. L. Val ◽  
D. J. Randall
Keyword(s):  
Sodium Nitrite ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Swimming Performance ◽  
Intraperitoneal Administration ◽  
Haemoglobin Concentration ◽  
Hydrodynamic Drag ◽  
Swimming Velocity ◽  
Oxygen Carrying Capacity ◽  
Mass Dependent

Nitrite oxidizes haemoglobin (Hb) to methaemoglobin (MetHb), which is unable to bind oxygen. Nitrite exposure can therefore be used as a tool to manipulate the oxygen-carrying capacity of the blood without changing haematocrit. The objective of this study is to examine the relationship between the critical swimming velocity (Ucrit) and the functional haemoglobin concentration ([Hb]) of the blood in adult chinook salmon. Functional [Hb] was reduced by increasing MetHb levels through intraperitoneal administration of a mass-dependent volume of sodium nitrite. In resting fish, MetHb levels were found to stabilize at 25 % of total [Hb] 3 h after the injection of 30 mg kg-1 sodium nitrite. Methaemoglobin levels increased in proportion to the amount of sodium nitrite injected and reached a maximum (following the injection of 90 mg kg-1 sodium nitrite) of 51.8 % in resting fish and 72 % in fish forced to swim to Ucrit. At 60 and 90 mg kg-1 sodium nitrite, MetHb formation was greater in exercised than in resting fish. A second-order regression revealed that Ucrit was virtually independent of functional [Hb] between 51 and 100 % of control functional [Hb], but was positively correlated with functional [Hb] below 51 % of total [Hb] (4.5 g dl-1). The insensitivity of Ucrit to a functional [Hb] greater than 51 % may be partly due to the exponential increase in aerobic metabolism required to provide the power to overcome hydrodynamic drag at higher water velocities. There were no significant changes in intraerythrocytic organic phosphate (adenylates and guanylates) concentrations standardized to [Hb] in swimming or resting fish over the range of MetHb levels induced in this study. Fish may encounter nitrite naturally; if MetHb levels become severely elevated as a result, swimming ability will be significantly impaired.

scholarly journals Sperm Numbers as a Paternity Guard in a Wild Bird

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 231
Author(s):  
Melissah Rowe ◽  
Annabel van Oort ◽  
Lyanne Brouwer ◽  
Jan T. Lifjeld ◽  
Michael S. Webster ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Sperm Competition ◽  
Ecological Factors ◽  
Fertilization Success ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Sexually Selected Traits ◽  
Paternity Success ◽  
Mating Conditions ◽  
Sperm Traits

Sperm competition is thought to impose strong selection on males to produce competitive ejaculates to outcompete rival males under competitive mating conditions. Our understanding of how different sperm traits influence fertilization success, however, remains limited, especially in wild populations. Recent literature highlights the importance of incorporating multiple ejaculate traits and pre-copulatory sexually selected traits in analyses aimed at understanding how selection acts on sperm traits. However, variation in a male’s ability to gain fertilization success may also depend upon a range of social and ecological factors that determine the opportunity for mating events both within and outside of the social pair-bond. Here, we test for an effect of sperm quantity and sperm size on male reproductive success in the red-back fairy-wren (Malurus melanocephalus) while simultaneously accounting for pre-copulatory sexual selection and potential socio-ecological correlates of male mating success. We found that sperm number (i.e., cloacal protuberance volume), but not sperm morphology, was associated with reproductive success in male red-backed fairy-wrens. Most notably, males with large numbers of sperm available for copulation achieved greater within-pair paternity success. Our results suggest that males use large sperm numbers as a defensive strategy to guard within-pair paternity success in a system where there is a high risk of sperm competition and female control of copulation. Finally, our work highlights the importance of accounting for socio-ecological factors that may influence male mating opportunities when examining the role of sperm traits in determining male reproductive success.

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