scholarly journals Sperm wars and the evolution of male fertility

Reproduction ◽  
2012 ◽  
Vol 144 (5) ◽  
pp. 519-534 ◽  
Author(s):  
Leigh W Simmons ◽  
John L Fitzpatrick
Keyword(s):  
Sperm Competition ◽  
Swimming Speed ◽  
Male Fertility ◽  
Seminal Fluid ◽  
Future Research ◽  
Sperm Length ◽  
Seminal Fluid Proteins ◽  
Control Male ◽  
Form And Function ◽  
And Function

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

scholarly journals Genetic coordination of sperm morphology and seminal fluid proteins promotes male reproductive success in Drosophila melanogaster

2021 ◽  
Author(s):  
Jake Galvin ◽  
Erica Larson ◽  
Sevan Yedigarian ◽  
Mohammad Rahman ◽  
Kirill Borziak ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Reproductive Success ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Fertilization Success ◽  
Male Reproductive Success ◽  
Sperm Length ◽  
Seminal Fluid Proteins ◽  
Female Remating ◽  
Paternity Success

Spermatozoal morphology is highly variable both among and within species and in ways that can significantly impact fertilization success. In Drosophila melanogaster, paternity success depends on sperm length of both competing males and length of the female's primary sperm storage organ. We found that genes upregulated in long sperm testes are enriched for lncRNAs and seminal fluid proteins (Sfps). Transferred in seminal fluid to the female during mating, Sfps are secreted by the male accessory glands (AG) and affect female remating rate, physiology, and behavior with concomitant advantages for male reproductive success. Despite being upregulated in long sperm testes, they have no known function in testis tissue. We found that Sex Peptide and ovulin (Acp26Aa) knockouts resulted in shorter sperm, suggesting that Sfps may regulate sperm length during spermatogenesis. However, knockout of AG function did not affect sperm length, suggesting that AG expression has no influence on spermatogenic processes. We also found that long sperm males are better able to delay female remating, suggesting higher Sfp expression in AG. These results might suggest that long sperm males have a double advantage in sperm competition by both delaying female remating, likely through transfer of more Sfps, and by resisting sperm displacement. However, we also found that this extra advantage does not necessarily translate to more progeny or higher paternity success. Thus, we found that multiple components of the ejaculate coordinate to promote male reproductive success at different stages of reproduction, but the realized fitness advantages in sperm competition are uncertain.

scholarly journals The Drosophila seminal proteome and its role in postcopulatory sexual selection

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200072 ◽  
Author(s):  
Stuart Wigby ◽  
Nora C. Brown ◽  
Sarah E. Allen ◽  
Snigdha Misra ◽  
Jessica L. Sitnik ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Current Knowledge ◽  
Future Research ◽  
Seminal Fluid Proteins ◽  
Scale Functions ◽  
Postcopulatory Sexual Selection ◽  
Evolutionary Force ◽  
Protein Classes

Postcopulatory sexual selection (PCSS), comprised of sperm competition and cryptic female choice, has emerged as a widespread evolutionary force among polyandrous animals. There is abundant evidence that PCSS can shape the evolution of sperm. However, sperm are not the whole story: they are accompanied by seminal fluid substances that play many roles, including influencing PCSS. Foremost among seminal fluid models is Drosophila melanogaster , which displays ubiquitous polyandry, and exhibits intraspecific variation in a number of seminal fluid proteins (Sfps) that appear to modulate paternity share. Here, we first consolidate current information on the identities of D. melanogaster Sfps. Comparing between D. melanogaster and human seminal proteomes, we find evidence of similarities between many protein classes and individual proteins, including some D. melanogaster Sfp genes linked to PCSS, suggesting evolutionary conservation of broad-scale functions. We then review experimental evidence for the functions of D. melanogaster Sfps in PCSS and sexual conflict. We identify gaps in our current knowledge and areas for future research, including an enhanced identification of PCSS-related Sfps, their interactions with rival sperm and with females, the role of qualitative changes in Sfps and mechanisms of ejaculate tailoring. This article is part of the theme issue ‘Fifty years of sperm competition’.

Conclusions

2015 ◽  
Author(s):  
Charlotte R. Potts
Keyword(s):  
Iron Age ◽  
Building Materials ◽  
Central Italy ◽  
Future Research ◽  
Main Body ◽  
Monumental Architecture ◽  
Form And Function ◽  
Religious Buildings ◽  
Religious Architecture ◽  
And Function

This book began by stating that histories of religious architecture can be accounts of both buildings and people. This particular history, focused on the archaeological evidence for the development of cult buildings in early central Italy, has reconsidered traditional narratives about the form and function of Etrusco-Italic religious architecture and proposed an alternative reconstruction of how their architects and audiences may have interacted with one another in Rome, Latium, and Etruria between the ninth and the sixth centuries BC. Comparison with the construction of monumental temples elsewhere also indicated that settlements including Rome, Satricum, Pyrgi, and Tarquinia can perhaps be considered part of a network of Archaic Mediterranean settlements with material, commercial, and religious connections, and that monumental architecture may have been a mechanism for successful social interaction. This study has therefore supported the suggestion that the physical and social fabric of ancient communities were closely linked, and that regional studies of Latium and Etruria may furthermore benefit from being set in Italic and Mediterranean contexts. This concluding chapter briefly recapitulates the arguments made in the main body of the book and the significance of each of those arguments for studies of ancient architecture and society. It also assesses how these findings relate to broader debates about Archaic Italy. Finally, it acknowledges the limitations of this analysis and highlights opportunities for future research. Part I of this book demonstrated that ancient religious architecture was a protean phenomenon. Three chapters analysed the ambiguous evidence for Iron Age sacred huts, the range of different buildings types associated with ritual activities in the seventh century BC, and the emergence of a separate architectural language for religious buildings during the Archaic period. Detailed analyses of foundations and roofs revealed that as changes in technology and society led to the widespread use of more permanent building materials, the physical fabric of central Italic settlements was also increasingly marked by the use of particular architectural forms and decorations to differentiate cult buildings from other structures, setting them apart in a form of architectural consecration.

scholarly journals Conceptual developments in sperm competition: a very brief synopsis

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200061 ◽  
Author(s):  
Geoff A. Parker
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Seminal Fluid ◽  
Female Reproduction ◽  
Internal Fertilization ◽  
Seminal Fluid Proteins ◽  
Competition Theory ◽  
Past Half Century ◽  
Mate Acquisition ◽  
Gamete Competition

The past half century has seen the development of the field of post-ejaculatory sexual selection, the sequel to sexual selection for mate-acquisition (pre-ejaculatory) described by Darwin. In richness and diversity of adaptations, post-ejaculatory selection rivals that of pre-ejaculatory sexual selection. Anisogamy—and hence two sexes—likely arose by primeval gamete competition, and sperm competition remains a major force maintaining high sperm numbers. The post-ejaculatory equivalent of male–male competition for matings, sperm competition was an intense ancestral form of sexual selection, typically weakening as mobility and internal fertilization developed in many taxa, when some expenditure became diverted into pre-ejaculatory competition. Sperm competition theory has been relatively successful in explaining variation in relative testes size and sperm numbers per ejaculate and is becoming more successful in explaining variation in sperm phenotype. Sperm competition has generated many other male adaptations such as seminal fluid proteins that variously modify female reproduction towards male interests, and copulatory plugs, prolonged copulations and post-ejaculatory guarding behaviour that reduce female remating probability, many of which result in sexual conflict. This short survey of conceptual developments is intended as a broad overview, mainly as a primer for new researchers. This article is part of the theme issue ‘Fifty years of sperm competition'.

scholarly journals Sperm form and function in the absence of sperm competition

2013 ◽  
Vol 81 (3) ◽  
pp. 204-216 ◽  
Author(s):  
Gerhard van der Horst ◽  
Liana Maree
Keyword(s):  
Sperm Competition ◽  
Form And Function ◽  
And Function

scholarly journals Primary Care Patient Records in the United Kingdom: Past, Present, and Future Research Priorities (Preprint)

2018 ◽  
Author(s):  
Brian McMillan ◽  
Robert Eastham ◽  
Benjamin Brown ◽  
Richard Fitton ◽  
David Dickinson
Keyword(s):  
Primary Care ◽  
United Kingdom ◽  
Primary Care Patient ◽  
Research Priorities ◽  
Care Patient ◽  
Patient Record ◽  
Future Research ◽  
Form And Function ◽  
The United Kingdom ◽  
And Function

UNSTRUCTURED This paper briefly outlines the history of the medical record and the factors contributing to the adoption of computerized records in primary care in the United Kingdom. It discusses how both paper-based and electronic health records have traditionally been used in the past and goes on to examine how enabling patients to access their own primary care record online is changing the form and function of the patient record. In addition, it looks at the evidence for the benefits of Web-based access and discusses some of the challenges faced in this transition. Finally, some suggestions are made regarding the future of the patient record and research questions that need to be addressed to help deepen our understanding of how they can be used more beneficially by both patients and clinicians.

scholarly journals Is Extreme in the Eye of the Beholder? An Experimental Assessment of Extremist Cognitions

2020 ◽  
pp. 088626052095864
Author(s):  
Neil Shortland ◽  
Elias Nader ◽  
Lisa Thompson ◽  
Marek Palasinski
Keyword(s):  
Future Research ◽  
Personality Factors ◽  
Psychological Consequences ◽  
Research Directions ◽  
Personality Differences ◽  
Form And Function ◽  
Individual Personality ◽  
Future Research Directions ◽  
And Function

Scholars have extensively discussed the topic of “online radicalization,” often seeking to understand the form and function of online extremist material. However, this work has neglected to examine the role that the Internet plays alongside individual personality factors in the process through which someone develops violent extremist cognitions. This article aims to extend the understanding of the role of personality differences in the effect of exposure to extremist material online. In this study, we experimentally measure the short-term psychological consequences of exposure to extremist material on extremist cognitions. We use a between-group experimental design in which participants are shown extremist propaganda with either pre- or post-counter messages. Our results indicate that trait personality, and specifically aggression, may be more influential than exposure to extremist propaganda in influencing extremist cognitions. We discuss the implications of these results in the context of future research directions.

scholarly journals Molecular Diversification of the Seminal Fluid Proteome in a Recently Diverged Passerine Species Pair

2019 ◽  
Vol 37 (2) ◽  
pp. 488-506 ◽  
Author(s):  
Melissah Rowe ◽  
Emma Whittington ◽  
Kirill Borziak ◽  
Mark Ravinet ◽  
Fabrice Eroukhmanoff ◽  
...  
Keyword(s):  
Seminal Fluid ◽  
Passer Domesticus ◽  
Species Pair ◽  
Seminal Fluid Proteins ◽  
Passerine Species ◽  
Immunity Genes ◽  
Evolutionary Genomic ◽  
Whole Genome Resequencing ◽  
And Function ◽  
Reproductive Processes

Abstract Seminal fluid proteins (SFPs) mediate an array of postmating reproductive processes that influence fertilization and fertility. As such, it is widely held that SFPs may contribute to postmating, prezygotic reproductive barriers between closely related taxa. We investigated seminal fluid (SF) diversification in a recently diverged passerine species pair (Passer domesticus and Passer hispaniolensis) using a combination of proteomic and comparative evolutionary genomic approaches. First, we characterized and compared the SF proteome of the two species, revealing consistencies with known aspects of SFP biology and function in other taxa, including the presence and diversification of proteins involved in immunity and sperm maturation. Second, using whole-genome resequencing data, we assessed patterns of genomic differentiation between house and Spanish sparrows. These analyses detected divergent selection on immunity-related SF genes and positive selective sweeps in regions containing a number of SF genes that also exhibited protein abundance diversification between species. Finally, we analyzed the molecular evolution of SFPs across 11 passerine species and found a significantly higher rate of positive selection in SFPs compared with the rest of the genome, as well as significant enrichments for functional pathways related to immunity in the set of positively selected SF genes. Our results suggest that selection on immunity pathways is an important determinant of passerine SF composition and evolution. Assessing the role of immunity genes in speciation in other recently diverged taxa should be prioritized given the potential role for immunity-related proteins in reproductive incompatibilities in Passer sparrows.

scholarly journals Navigating Regional Environmental Governance

2012 ◽  
Vol 12 (3) ◽  
pp. 1-17 ◽  
Author(s):  
Jörg Balsiger ◽  
Stacy D. VanDeveer
Keyword(s):  
Environmental Governance ◽  
Empirical Work ◽  
Multilevel Governance ◽  
Theory And Practice ◽  
Future Research ◽  
Environmental Cooperation ◽  
Quantitative Evidence ◽  
Form And Function ◽  
Global Environmental ◽  
And Function

Global environmental governance is growing increasingly complex and recent scholarship and practice raise a number of questions about the continued feasibility of negotiating and implementing an ever-larger set of global environmental agreements. In the search for alternative conceptual models and normative orders, regional environmental governance (REG) is (re)emerging as a significant phenomenon in theory and practice. Although environmental cooperation has historically been more prevalent at the regional than at the global level, and has informed much of what we know today about international environmental cooperation, REG has been a neglected topic in the scholarly literature on international relations and international environmental politics. This introduction to the special issue situates theoretical arguments linked to REG in the broader literature, including the nature of regions, the location of regions in multilevel governance, and the normative arguments advanced for and against regional orders. It provides an overview of empirical work; offers quantitative evidence of REG's global distribution; advances a typology of REG for future research; and introduces the collection of research articles and commentaries through the lens of three themes: form and function, multilevel governance, and participation.

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