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Parker GA. Conceptual developments in sperm competition: a very brief synopsis. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200061. [PMID: 33070727 DOI: 10.1098/rstb.2020.0061] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
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'.
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Affiliation(s)
- Geoff A Parker
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK
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Abstract
Sperm competition was defined by Geoff Parker 50 years ago as the competition between sperm from two or more males over the fertilization of a set of eggs. Since the publication of his seminal paper, sperm competition has developed into a large field of research, and many aspects are still being discovered. One of the relatively poorly understood aspects is the importance of selection and competition among sperm within the ejaculate of a male. The sheer number of sperm present in a male's ejaculate suggests that the competition among sibling sperm produced by the same male may be intense. In this review, we summarize Parker's theoretical models generating predictions about the evolution of sperm traits under the control of the haploid gamete as opposed to the diploid male. We review the existing evidence of within-ejaculate competition from a wide range of fields and taxa. We also discuss the conceptual and practical hurdles we have been facing to study within-ejaculate sperm competition, and how novel technologies may help in addressing some of the currently open questions. This article is part of the theme issue ‘Fifty years of sperm competition’.
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Affiliation(s)
- Andreas Sutter
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Simone Immler
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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Whittington E, Karr TL, Mongue AJ, Dorus S, Walters JR. Evolutionary Proteomics Reveals Distinct Patterns of Complexity and Divergence between Lepidopteran Sperm Morphs. Genome Biol Evol 2020; 11:1838-1846. [PMID: 31268533 PMCID: PMC6607854 DOI: 10.1093/gbe/evz080] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2019] [Indexed: 12/18/2022] Open
Abstract
Spermatozoa are one of the most strikingly diverse animal cell types. One poorly understood example of this diversity is sperm heteromorphism, where males produce multiple distinct morphs of sperm in a single ejaculate. Typically, only one morph is capable of fertilization and the function of the nonfertilizing morph, called parasperm, remains to be elucidated. Sperm heteromorphism has multiple independent origins, including Lepidoptera (moths and butterflies), where males produce a fertilizing eupyrene sperm and an apyrene parasperm, which lacks a nucleus and nuclear DNA. Here we report a comparative proteomic analysis of eupyrene and apyrene sperm between two distantly related lepidopteran species, the monarch butterfly (Danaus plexippus) and Carolina sphinx moth (Manduca sexta). In both species, we identified ∼700 sperm proteins, with half present in both morphs and the majority of the remainder observed only in eupyrene sperm. Apyrene sperm thus have a distinctly less complex proteome. Gene ontology (GO) analysis revealed proteins shared between morphs tend to be associated with canonical sperm cell structures (e.g., flagellum) and metabolism (e.g., ATP production). GO terms for morph-specific proteins broadly reflect known structural differences, but also suggest a role for apyrene sperm in modulating female neurobiology. Comparative analysis indicates that proteins shared between morphs are most conserved between species as components of sperm, whereas morph-specific proteins turn over more quickly, especially in apyrene sperm. The rapid divergence of apyrene sperm content is consistent with a relaxation of selective constraints associated with fertilization and karyogamy. On the other hand, parasperm generally exhibit greater evolutionary lability, and our observations may therefore reflect adaptive responses to shifting regimes of sexual selection.
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Affiliation(s)
- Emma Whittington
- Center for Reproductive Evolution, Department of Biology, Syracuse University
| | - Timothy L Karr
- Center for Mechanisms of Evolution, The Biodesign Institute, Arizona State University
| | - Andrew J Mongue
- Department of Ecology and Evolutionary Biology, University of Kansas
| | - Steve Dorus
- Center for Reproductive Evolution, Department of Biology, Syracuse University
| | - James R Walters
- Department of Ecology and Evolutionary Biology, University of Kansas
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Piras F, Biagi F, Floris A, Farina V, Zedda M, Franzoi P, Carcupino M. Intra- and intermale variability of mature sperm traits analysed in two brackish water populations of the pipefish Syngnathus abaster (Syngnathidae). ACTA ZOOL-STOCKHOLM 2015. [DOI: 10.1111/azo.12115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Francesca Piras
- Dipartimento di Scienze della Natura e del Territorio; Università di Sassari; Sassari Italy
| | - Francesca Biagi
- Dipartimento di Medicina Veterinaria; Università di Sassari; Sassari Italy
| | - Antonello Floris
- Dipartimento di Medicina Veterinaria; Università di Sassari; Sassari Italy
| | - Vittorio Farina
- Dipartimento di Medicina Veterinaria; Università di Sassari; Sassari Italy
| | - Marco Zedda
- Dipartimento di Medicina Veterinaria; Università di Sassari; Sassari Italy
| | - Piero Franzoi
- Dipartimento di Scienze Ambientali; Informatica e Statistica; Università Ca' Foscari di Venezia; Venezia Italy
| | - Marcella Carcupino
- Dipartimento di Scienze della Natura e del Territorio; Università di Sassari; Sassari Italy
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Shepardson SP, Heard WH, Breton S, Hoeh WR. Light and Transmission Electron Microscopy of Two Spermatogenic Pathways and Unimorphic Spermatozoa inVenustaconcha ellipsiformis(Conrad, 1836) (Bivalvia: Unionoida). MALACOLOGIA 2012. [DOI: 10.4002/040.055.0207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Higginson DM, Pitnick S. Evolution of intra-ejaculate sperm interactions: do sperm cooperate? Biol Rev Camb Philos Soc 2010; 86:249-70. [PMID: 20608927 DOI: 10.1111/j.1469-185x.2010.00147.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dawn M Higginson
- Department of Biology, Syracuse University, New York 13244, USA.
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Abstract
The idea of subfertile or altogether infertile sperm seems an evolutionary paradox, so why have they evolved in a diverse set of species, from molluscs to mice? Understanding sperm sociality may provide the answer.
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Affiliation(s)
- Tommaso Pizzari
- Edward Grey Institute in Department of Zoology of University of Oxford, Oxford, United Kingdom.
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Holman L, Freckleton RP, Snook RR. What use is an infertile sperm? A comparative study of sperm-heteromorphic Drosophila. Evolution 2007; 62:374-85. [PMID: 18053077 DOI: 10.1111/j.1558-5646.2007.00280.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sperm size and number are important determinants of male reproductive success. The genus Drosophila exhibits a remarkable diversity of sperm production strategies, including the production of multiple sperm morphs by individual males, a phenomenon called sperm heteromorphism. Sperm-heteromorphic Drosophila species in the obscura group produce large numbers of infertile "parasperm" in addition to fertile eusperm. Parasperm have been hypothesized to perform a number of roles in place of fertilization, predominantly focused on their potential function in postcopulatory sexual selection. However, the evolutionary significance of parasperm remains unknown. Here we measured several male and female morphological, behavioral, and life-history traits in 13 obscura group species to test competing hypotheses of parasperm function using comparative methods. We found that parasperm size was unrelated to female reproductive tract morphology but was negatively related to our two indices of sperm competition, suggesting that postcopulatory sexual selection may indeed have shaped the evolution of parasperm. We also found abundant coevolution between male and female reproductive traits. Some of these relationships have been found in both sperm-monomorphic and sperm-heteromorphic taxa, but others are dissimilar. We discuss the significance of our results to the evolution of reproductive traits and the elusive function of Drosophila parasperm.
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Affiliation(s)
- Luke Holman
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
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Shackelford TK, Pound N, Goetz AT. Psychological and Physiological Adaptations to Sperm Competition in Humans. REVIEW OF GENERAL PSYCHOLOGY 2005. [DOI: 10.1037/1089-2680.9.3.228] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Postcopulatory competition between males, in the form of sperm competition, is a widespread phenomenon in many animal species. The extent to which sperm competition has been an important selective pressure during human evolution remains controversial, however. The authors review critically the evidence that human males and females have psychological, behavioral, and physiological adaptations that evolved in response to selection pressures associated with sperm competition. The authors consider, using evidence from contemporary societies, whether sperm competition is likely to have been a significant adaptive problem for ancestral humans and examine the evidence suggesting that human males have physiological and psychological mechanisms that allow for “prudent” sperm allocation in response to variations in the risk of sperm competition.
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Affiliation(s)
| | - Nicholas Pound
- Centre for Cognition and Neuroimaging, Brunel University, Uxbridge, England
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Bernasconi G, Hellriegel B. Fertilization competence and sperm size variation in sperm-heteromorphic insects. Evol Ecol 2005. [DOI: 10.1007/s10682-004-7594-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Till-Bottraud I, Joly D, Lachaise D, Snook RR. Pollen and sperm heteromorphism: convergence across kingdoms? J Evol Biol 2005; 18:1-18. [PMID: 15669956 DOI: 10.1111/j.1420-9101.2004.00789.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sperm competition theory predicts that males should produce many, similar sperm. However, in some species of animals and plants, males exhibit a heteromorphism that results in the production of at least two different types of sperm or pollen grains. In animals, sperm heteromorphism typically corresponds to the production of one fertile morph and one (or more) sterile morph(s), whereas in plants two or more pollen morphs (one of which can be either sterile or fertile) are produced in all flowers but sometimes in different anthers. Heteromorphism has arisen independently several times across phyla and at different phylogenetic levels. Here, we compare and contrast sperm and pollen heteromorphism and discuss the evolutionary hypotheses suggested to explain heteromorphism in these taxa. These hypotheses include facilitation, nutritive contribution, blocking, cheap filler, sperm flushing or killing for animals; outcrossing and precise cross-pollen transfer or bet-hedging strategy for plants; cryptic female choice for both. We conclude that heteromorphism in the two phyla is most likely linked to a general evolutionary response to sexual selection, either to increase one male's sperm or pollen success in competition with other males, or mediate male/female interactions. Therefore, although sperm and pollen are not homologous, we suggest that heteromorphism represents an example of convergence across kingdoms.
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Vladić TV, Afzelius BA, Bronnikov GE. Sperm quality as reflected through morphology in salmon alternative life histories. Biol Reprod 2002; 66:98-105. [PMID: 11751270 DOI: 10.1095/biolreprod66.1.98] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Male salmon exhibit alternative mating strategies, as both older anadromous adults and precocious juveniles (parr) participate in the spawning of a single female. This study tested the following hypotheses: 1) different intensities of sperm competition may reflect different sperm tail optima; 2) long spermatozoa are superior to short ones, with an associated cost on sperm longevity; and 3) a disfavored role in sperm competition selects for parr investing more in sperm quality. Comparisons included sperm morphological traits, whereas sperm quality was investigated by motility duration observations, measurement of the sperm adenylate system, and fertilization experiments. No evidence of different adaptive sperm dimensions between the male types was found. Positive association between spermatocrit and energy charge was, however, detected. Sperm length parameters correlated positively with ATP, energy charge, and fertilization success, whereas no evidence for an effect of sperm morphology on longevity was found. Male parr had greater spermatocrit than adults and fertilized equal proportions of eggs as adults despite a pronounced numerical subordinance in the fertilization experiments. It is concluded that a long sperm tail and midpiece may be selected to optimize energetic demands under conditions of increased sperm competition intensity.
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Affiliation(s)
- Tomislav V Vladić
- Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden.
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