scholarly journals Exposure to sperm competition risk improves survival of virgin males

2013 ◽  
Vol 9 (2) ◽  
pp. 20121188 ◽  
Author(s):  
Joshua P. Moatt ◽  
Calvin Dytham ◽  
Michael D. F. Thom
Keyword(s):  
Sperm Competition ◽  
Life History Traits ◽  
Seminal Fluid ◽  
Fluid Composition ◽  
Short Term ◽  
Investment In Reproduction ◽  
Sperm Competition Risk ◽  
Total Investment ◽  
Improvement In Survival ◽  
Striking Effect

Sperm competition between the ejaculates of multiple males for the fertilization of a given set of ova is taxonomically widespread. Males have evolved remarkable adaptations to increase their reproductive success under postcopulatory sexual selection, which in many species includes the ability to modify behaviour and ejaculate characteristics plastically to match the perceived level of sperm competition. Males of the model species Drosophila melanogaster increase mating duration and modify seminal fluid composition in response to short-term changes in sperm competition risk. If these responses increase a male's total investment in reproduction, he must either trade-off this cost against other life-history traits or suffer reduced survival. We tested whether mounting a plastic sperm competition response bears an instantaneous survival cost, and instead found that male D. melanogaster exposed to a high risk of sperm competition survive 12 per cent longer than those at low risk, equating to a 49 per cent reduction in the hourly hazard of death. This striking effect was found only among virgins: the high cost of mating in this species eliminates any such benefit among non-virgin males. Our results suggest that the improvement in survival found among virgins may be a product of males’ tactical responses to sperm competition.

scholarly journals Social manipulation of sperm competition intensity reduces seminal fluid gene expression

2018 ◽  
Vol 14 (1) ◽  
pp. 20170659 ◽  
Author(s):  
Nadia S. Sloan ◽  
Maxine Lovegrove ◽  
Leigh W. Simmons
Keyword(s):  
Gene Expression ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Fertilization Success ◽  
Accessory Gland ◽  
Fluid Composition ◽  
Competition Intensity ◽  
Teleogryllus Oceanicus ◽  
Sperm Competition Risk ◽  
Considerable Body

A considerable body of evidence supports the prediction that males should increase their expenditure on the ejaculate in response to sperm competition risk. The prediction that they should reduce their expenditure with increasing sperm competition intensity is less well supported. Moreover, most studies have documented plasticity in sperm numbers. Here we show that male crickets Teleogryllus oceanicus exhibit reduced seminal fluid gene expression and accessory gland mass in response to elevated sperm competition intensity. Together with previous research, our findings suggest that strategic adjustments in seminal fluid composition contribute to competitive fertilization success in this species.

scholarly journals Sperm competition risk drives plasticity in seminal fluid composition

BMC Biology ◽  
2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Steven A. Ramm ◽  
Dominic A. Edward ◽  
Amy J. Claydon ◽  
Dean E. Hammond ◽  
Philip Brownridge ◽  
...  
Keyword(s):  
Sperm Competition ◽  
Seminal Fluid ◽  
Fluid Composition ◽  
Sperm Competition Risk

scholarly journals Socially cued seminal fluid gene expression mediates responses in ejaculate quality to sperm competition risk

2017 ◽  
Vol 284 (1861) ◽  
pp. 20171486 ◽  
Author(s):  
Leigh W. Simmons ◽  
Maxine Lovegrove
Keyword(s):  
Gene Expression ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Protein Composition ◽  
Theoretical Models ◽  
Fluid Composition ◽  
Sperm Viability ◽  
Considerable Evidence ◽  
Sperm Competition Risk ◽  
Seminal Fluid Protein

There is considerable evidence that males will increase the number of sperm ejaculated in response to sperm competition risk. However, whether they have the capacity to adjust seminal fluid components of the ejaculate has received less attention. Male crickets ( Teleogryllus oceanicus ) have been shown to adjust the viability of sperm in their ejaculate in response to sperm competition risk. Here we show that socially mediated plasticity in sperm viability is probably due, at least in part, to male adjustments in the protein composition of the seminal fluid. Seven seminal fluid protein genes were found to have an increased expression in males exposed to rival calls. Increased expression of these genes was correlated with increased sperm viability in whole ejaculates, and gene knockdown confirmed that at least one of these proteins promotes sperm viability. Our results lend support for recent theoretical models that predict complex responses in male allocation to seminal fluid composition in response to sperm competition risk.

scholarly journals Social status and ejaculate composition in the house mouse

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200083 ◽  
Author(s):  
Helen L. Bayram ◽  
Catarina Franco ◽  
Philip Brownridge ◽  
Amy J. Claydon ◽  
Natalie Koch ◽  
...  
Keyword(s):  
Social Status ◽  
Sperm Competition ◽  
Seminal Vesicle ◽  
House Mouse ◽  
Seminal Fluid ◽  
Fluid Composition ◽  
Investment Strategies ◽  
Mus Musculus Domesticus ◽  
Competition Theory ◽  
Similar Body

Sperm competition theory predicts that males should tailor ejaculates according to their social status. Here, we test this in a model vertebrate, the house mouse ( Mus musculus domesticus ), combining experimental data with a quantitative proteomics analysis of seminal fluid composition. Our analyses reveal that both sperm production and the composition of proteins found in seminal vesicle secretions differ according to social status. Dominant males invested more in ejaculate production overall. Their epididymides contained more sperm than those of subordinate or control males, despite similar testes size between the groups. Dominant males also had larger seminal vesicle glands than subordinate or control males, despite similar body size. However, the seminal vesicle secretions of subordinate males had a significantly higher protein concentration than those of dominant males. Moreover, detailed proteomic analysis revealed subtle but consistent differences in the composition of secreted seminal vesicle proteins according to social status, involving multiple proteins of potential functional significance in sperm competition. These findings have significant implications for understanding the dynamics and outcome of sperm competition, and highlight the importance of social status as a factor influencing both sperm and seminal fluid investment strategies. This article is part of the theme issue ‘Fifty years of sperm competition’.

scholarly journals SPERM COMPETITION AND THE EVOLUTION OF SEMINAL FLUID COMPOSITION

Evolution ◽  
2014 ◽  
Vol 68 (10) ◽  
pp. 3008-3019 ◽  
Author(s):  
Sumit Dhole ◽  
Maria R. Servedio
Keyword(s):  
Sperm Competition ◽  
Seminal Fluid ◽  
Fluid Composition

scholarly journals Sperm competition risk drives rapid ejaculate adjustments mediated by seminal fluid

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Michael J Bartlett ◽  
Tammy E Steeves ◽  
Neil J Gemmell ◽  
Patrice C Rosengrave
Keyword(s):  
Sperm Competition ◽  
Oncorhynchus Tshawytscha ◽  
Seminal Fluid ◽  
Sperm Velocity ◽  
Competition Theory ◽  
Increased Risk ◽  
Rapid Changes ◽  
Sperm Competition Risk ◽  
Rapid Adjustment

In many species, males can make rapid adjustments to ejaculate performance in response to sperm competition risk; however, the mechanisms behind these changes are not understood. Here, we manipulate male social status in an externally fertilising fish, chinook salmon (Oncorhynchus tshawytscha), and find that in less than 48 hr, males can upregulate sperm velocity when faced with an increased risk of sperm competition. Using a series of in vitro sperm manipulation and competition experiments, we show that rapid changes in sperm velocity are mediated by seminal fluid and the effect of seminal fluid on sperm velocity directly impacts paternity share and therefore reproductive success. These combined findings, completely consistent with sperm competition theory, provide unequivocal evidence that sperm competition risk drives plastic adjustment of ejaculate quality, that seminal fluid harbours the mechanism for the rapid adjustment of sperm velocity and that fitness benefits accrue to males from such adjustment.

scholarly journals Sperm competition in tropical versus temperate zone birds

2013 ◽  
Vol 280 (1752) ◽  
pp. 20122434 ◽  
Author(s):  
Tomáš Albrecht ◽  
Oddmund Kleven ◽  
Jakub Kreisinger ◽  
Terje Laskemoen ◽  
Taiwo C. Omotoriogun ◽  
...  
Keyword(s):  
Sperm Competition ◽  
Life History Traits ◽  
Multivariate Model ◽  
Temperate Zone ◽  
Tropical Species ◽  
Migration Distance ◽  
Novel Approach ◽  
Sperm Competition Risk ◽  
Sperm Size ◽  
Reduced Risk

Sperm competition represents an important component of post-copulatory sexual selection. It has been argued that the level of sperm competition declines in birds towards the equator. However, to date, sperm competition estimates have been available mainly for avian species inhabiting the northern temperate zone. Here we apply a novel approach, using the coefficient of between-male variation (CV bm ) in sperm size as an index for sperm competition risk, in a comparative analysis of 31 Afrotropical and 99 northern temperate zone passerine species. We found no difference in sperm competition risk between the two groups, nor any relationship with migration distance. However, a multivariate model indicated that sperm competition risk was highest in species with a combination of low body mass and few eggs per clutch. The effect of clutch size was most pronounced in tropical species, which indicates that sperm competition risk in tropical and temperate species is differently associated with particular life-history traits. Although tropical species had lower sperm competition risk than temperate zone species for overlapping clutch sizes, the idea of a generally reduced risk of sperm competition in tropical birds was not supported by our analysis.

scholarly journals Tactic-specific differences in seminal fluid influence sperm performance

2013 ◽  
Vol 280 (1755) ◽  
pp. 20122891 ◽  
Author(s):  
Lisa Locatello ◽  
Federica Poli ◽  
Maria B. Rasotto
Keyword(s):  
Sperm Competition ◽  
Seminal Fluid ◽  
Fertilization Rate ◽  
Fertilization Success ◽  
Mating Tactics ◽  
Recognition Mechanism ◽  
Self Recognition ◽  
Sperm Competition Risk ◽  
Grass Goby ◽  
Zosterisessor Ophiocephalus

Seminal fluid often makes up a large part of an ejaculate, yet most empirical and theoretical studies on sperm competition have focused on how sperm characteristics (number and quality) affect fertilization success. However, seminal fluid influences own sperm performance and may potentially influence the outcome of sperm competition, by also affecting that of rivals. As a consequence males may be expected to allocate their investment in both sperm and seminal fluid in relation to the potential level of competition. Grass goby ( Zosterisessor ophiocephalus ) is an external fertilizer with guard-sneaker mating tactics, where sperm competition risk varies according to the tactic adopted. Here, we experimentally manipulated grass goby ejaculates by separately combining sperm and seminal fluid from territorial and sneaker males. While sperm of sneaker and territorial males did not differ in their performance when they interacted with their own seminal fluid only, sperm of sneakers increased their velocity and fertilization rate in the presence of territorial males' seminal fluid. By contrast, sneaker males' seminal fluid had a detrimental effect on the performance of territorial males' sperm. Sperm velocity was unaffected by the seminal fluid of males employing the same tactic, suggesting that seminal fluid's effect on rival-tactic sperm is not based on a self/non-self recognition mechanism. Our findings show that cross interactions of sperm and seminal fluid may influence the fertilization success of competing ejaculates with males investing in both sperm and seminal fluid in response to sperm competition risk.

scholarly journals Black goby territorial males adjust their ejaculate's characteristics in response to the presence of sneakers

2021 ◽  
Vol 17 (8) ◽  
pp. 20210201
Author(s):  
Lisa Locatello ◽  
Oliviero Borgheresi ◽  
Federica Poli ◽  
Andrea Pilastro ◽  
Maria B. Rasotto
Keyword(s):  
Sperm Competition ◽  
Seminal Fluid ◽  
Adaptive Plasticity ◽  
Fluid Composition ◽  
Field Observations ◽  
Sperm Release ◽  
Territory Defence

In many species, males can rapidly adjust their ejaculate performance in response to changing levels of sperm competition, an ability that is probably mediated by seminal fluid adaptive plasticity. In the black goby, Gobius niger , territorial males attach viscous ejaculate trails to the nest roof, from which sperm are slowly released into the water during the long-lasting spawning events. Sneaker males release their sperm in the vicinity of the nest, and territorial males try to keep them at a distance by patrolling their territory. We show here that territorial males' ejaculate trails released a higher proportion of their sperm in the presence of a single sneaker, but this proportion decreased when there were three sneakers, an effect that is most likely mediated by a change in the seminal fluid composition. Field observations showed that when multiple sneaking attempts occurred, territorial males spent more time outside the nest, suggesting that ejaculation rate and territory defence are traded-off. Altogether, these results suggest that the adjustment of sperm release from the ejaculate may be strategic, guaranteeing a more continuous concentration of the territorial male's sperm in the nest, although at a lower level, when he is engaged in prolonged territory defence outside the nest.

Sign in / Sign up

Export Citation Format

Share Document