Sperm wars and the evolution of male fertility

Reproduction, Journal Year: 2012, Volume and Issue: 144(5), P. 519 - 534

Published: Sept. 15, 2012

Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected shape male expenditure on the ejaculate. Here, we review empirical data illustrate evolutionary consequences of competition. favors evolution increased testes size and production. In some species, males appear capable adjusting number ejaculated, depending perceived levels Selection also act form function, although evidence for this remains equivocal. Comparative studies suggest length swimming speed may increase in response selection from However, mechanisms driving pattern remain unclear. Evidence influences mixed fertilization trials performed across broad range species demonstrate inconsistent relationships between function. This ambiguity part reflect important role seminal fluid proteins (sfps) play affecting There good sfps are subject competition, recent work pointing an ability adjust their chemistry rival males. We argue future research must consider components ejaculate as functional unity. Research at genomic level will identify genes ultimately control fertility.

Language: Английский

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Mining of deep-sea seafloor massive sulfides: A review of the deposits, their benthic communities, impacts from mining, regulatory frameworks and management strategies

Ocean & Coastal Management, Journal Year: 2013, Volume and Issue: 84, P. 54 - 67

Published: Aug. 6, 2013

Seafloor massive sulfide (SMS) deposits form in a suite of hydrothermal settings across range depths. Many are tonnage and mineral grade comparable to land attractive mining companies. Economically viable can be either active or inactive, with different biological communities present at each. These benthic may include specially adapted endemic fauna that could severely impacted by activity. Although there is currently no SMS mining, recent research from Industry scientific investigations able inform decisions on the management deposits, including appropriate mitigation strategies minimise impact activities. Mitigation will likely focus facilitating recolonisation areas spatial open closed reducing effects sediment plumes Regulation activity complex, falling under national international legislation alongside codes practice issued industry other stakeholders. Despite decades effort, still many unknowns about ecology particular for inactive sites genetic demographic connectivity populations among deposits. With considerable interest exploitation Western South Pacific Ocean, an urgent need assess potential particularly fauna, so designed implemented.

Language: Английский

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Sexual selection and the evolution of sperm quality

Molecular Human Reproduction, Journal Year: 2014, Volume and Issue: 20(12), P. 1180 - 1189

Published: Oct. 16, 2014

Sperm experience intense and varied selection that dramatically impacts the evolution of sperm quality. Selection acts to ensure are fertilization-competent able overcome many challenges experienced on their way towards eggs. However, simply being fertilize an egg is not enough male fertility in most species. Owing prevalence female multiple mating throughout animal kingdom, successful fertilization requires outcompete rival sperm. In addition, females can actively influence quality, storage or utilization fertility. This review provides overview how these selective forces After exploring link between traits fertility, we examine post-mating competition ejaculates influences We then describe complex genetic, social sexual interactions focusing importance seminal fluid female's reproductive tract. light complexities traits, greater use multivariate approaches incorporate male–male, sperm–sperm sperm–female study quality will enhance our understanding factors influencing Because metric success—fertilization—is same across argue information about gained from non-human animals has enormous potential further impact human

Language: Английский

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Sperm Competition, Sperm Numbers and Sperm Quality in Muroid Rodents

PLoS ONE, Journal Year: 2011, Volume and Issue: 6(3), P. e18173 - e18173

Published: March 25, 2011

Sperm competition favors increases in relative testes mass and production efficiency, changes sperm phenotype that result faster swimming speeds. However, little is known about its effects on traits contribute to determine the quality of a whole ejaculate (i.e., proportion motile, viable, morphologically normal acrosome intact sperm) are key determinants fertilization success. Two competing hypotheses lead alternative predictions: (a) quantity co-evolve under because they play complementary roles determining ejaculate's competitive ability, or (b) energetic constraints force trade-offs between depending their relevance providing advantage. We examined relationships levels, quantity, quality, comparative study 18 rodent species using phylogenetically controlled analyses. Total numbers were positively correlated proportions sperm, integrity motile sperm; latter three also significantly related among themselves, suggesting no traits. In addition, corrected for body mass), showed strong association with numbers, positive significant associations all exception live sperm. An "overall quality" parameter obtained by principal component analysis (which explained 85% variance) was more strongly associated than any individual trait. Overall as numbers. Thus, improve an integrated manner combination what makes ejaculates competitive. evolutionary terms this implies complex network genetic developmental pathways underlying processes formation, maturation, transport female reproductive tract, preparation must evolve concert.

Language: Английский

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Comparative analysis of mammalian sperm ultrastructure reveals relationships between sperm morphology, mitochondrial functions and motility

Reproductive Biology and Endocrinology, Journal Year: 2019, Volume and Issue: 17(1)

Published: Aug. 15, 2019

Sperm morphology mainly refers to the shape of head, length flagellar segments, including midpiece, principal piece and end piece, size accessory structures, axonemes, outer dense fibers (ODFs), mitochondrial sheath (MS) fibrous (FS). Across species, there is considerable diversity in morphology. An established theory posits that sperm flagellum, especially a critical factor influencing metabolism velocity. However, our understanding relationships between ultrastructures incomplete. The morphologies from 10 mammalian human, mouse, rat, dog, rabbit, goat, pig, bull, guinea pig golden hamster, were examined by scanning electron microscopy (SEM) transmission (TEM). According SEM TME images, heads cross-sectional areas structures flagella width measured using Image J software. variation tendencies (referred as slope) along calculated linear regression method. Mitochondrial functions commercial kits. velocities CASA three-dimensional species slopes internal obtained. axoneme tapered slightly base tip axonemes correlated negatively with variability across species. Additionally, ODFs and/or MS positively lengths total well velocities. volumes ATP content swimming Our results not only show relationship physiology but also provide sizes mitochondria new targets which study regulation

Language: Английский

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Computer assisted sperm morphometry in mammals: A review

Animal Reproduction Science, Journal Year: 2015, Volume and Issue: 156, P. 1 - 12

Published: March 10, 2015

Language: Английский

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Do male secondary sexual characters signal ejaculate quality? A meta‐analysis

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2013, Volume and Issue: 88(3), P. 669 - 682

Published: Feb. 4, 2013

There are two reasons why researchers interested in the phenotypic relationship between expression of male secondary sexual characters (SSCs) and 'ejaculate quality' (defined as sperm/ejaculate traits that widely assumed to increase female fertility and/or sperm competitiveness). First, if is positive then females could gain a direct benefit by choosing more attractive males for assurance ('the phenotype-linked fertility' hypothesis). Second, there much interest direction correlation favoured pre-copulatory selection (i.e. affecting mating success) those post-copulatory increasing If negative this lead forms counteracting each other. Theory predicts be either or depending on underlying genetic variance covariance trait, extent variation among condition (resources available allocate reproductive traits), cost rate mating. We conducted meta-analysis determine average behavioural morphological four assays ejaculate quality (sperm number, viability, swimming speed size). Regardless how data were partitioned mean was consistently positive, but always statistically non-significant. The only exception character weakly significantly positively correlated with viability (r = 0.07, P < 0.05). no significant difference strength SSCs, nor relationships using assays. implications our findings discussed.

Language: Английский

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Cryotolerance of stallion spermatozoa is related toROSproduction and mitochondrial membrane potential rather than to the integrity of sperm nucleus

Andrology, Journal Year: 2014, Volume and Issue: 3(2), P. 395 - 407

Published: Oct. 8, 2014

Although cryopreservation of stallion spermatozoa allows long-term preservation from particular stallions and facilitates international trade, it is understood to inflict damages on sperm cells that may finally reduce their fertilizing ability. In addition, individual differences are known exist in the ability withstand freeze-thawing protocols. To date, these have mainly been reported basis motility membrane integrity. For this reason, present work sought determine between good (good freezability ejaculates: GFE) poor (poor PFE) ejaculates other parameters, including peroxide superoxide levels, potential mitochondrial nuclear With purpose, a total 24 were cryopreserved classified into two groups (GFE vs. PFE), depending integrity after freeze-thawing. From ejaculates, 13 as GFE 11 PFE. Apart permeability lipid disorder freeze-thawing, presented significantly (p < 0.05) higher percentages viable with high content peroxides superoxides than contrast, despite increasing DNA fragmentation disrupting disulphide bonds head proteins, no significant PFE seen. We can thus conclude differ reactive oxygen species levels cryopreservation, but not damage extent nucleus.

Language: Английский

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Importance of sperm morphology during sperm transport and fertilization in mammals

Asian Journal of Andrology, Journal Year: 2016, Volume and Issue: 18(6), P. 844 - 844

Published: Jan. 1, 2016

After natural or artificial insemination, the spermatozoon starts a journey from site of deposition to place fertilization. However, only small subset spermatozoa deposited achieves their goal: reach and fertilize egg. Factors involved in controlling sperm transport fertilization include female reproductive tract environment, cell-cell interactions, gene expression, phenotypic traits. Some significant determinants are known (i.e., motility DNA status), but many traits still indecipherable. One example is influence dimensions shape upon within genital towards oocyte. Biophysical associations between size may progression through tract, uncertainties remain concerning how morphology influences process, whether per se involved. Moreover, such explanations do not allow possibility that capable distinguishing fertile on basis morphology, as seems be case with biochemical, molecular, genetic properties. This review focuses evolution putative role selection uterus ability

Language: Английский

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POLYANDRY REDUCES SPERM LENGTH VARIATION IN SOCIAL INSECTS

Evolution, Journal Year: 2011, Volume and Issue: 65(10), P. 3006 - 3012

Published: May 12, 2011

Postcopulatory sexual selection, either in the form of sperm competition or cryptic female choice, is an important selective force that thought to have generated enormous variation morphology observed interspecifically. However, evolutionary significance intraspecific morphology, and role postcopulatory selection plays influencing this variation, remains poorly investigated invertebrates. Here, we tested hypothesis reduces both between within males, 27 species eusocial ants bees. These offer unusual opportunity assess how acts on variance as haploid males produce clonal, does not experience haploid-diploid conflict. We provide solid evidence polyandrous ant bee indeed less-variable sperm, indicating selected for superior quality. Our results a mechanistic explanation evolution high-quality comprehensive social insects influenced by selection.

Language: Английский

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