1
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Baur J, Zwoinska M, Koppik M, Snook RR, Berger D. Heat stress reveals a fertility debt owing to postcopulatory sexual selection. Evol Lett 2024; 8:101-113. [PMID: 38370539 PMCID: PMC10872150 DOI: 10.1093/evlett/qrad007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 01/21/2023] [Accepted: 02/21/2023] [Indexed: 02/20/2024] Open
Abstract
Climates are changing rapidly, demanding equally rapid adaptation of natural populations. Whether sexual selection can aid such adaptation is under debate; while sexual selection should promote adaptation when individuals with high mating success are also best adapted to their local surroundings, the expression of sexually selected traits can incur costs. Here we asked what the demographic consequences of such costs may be once climates change to become harsher and the strength of natural selection increases. We first adopted a classic life history theory framework, incorporating a trade-off between reproduction and maintenance, and applied it to the male germline to generate formalized predictions for how an evolutionary history of strong postcopulatory sexual selection (sperm competition) may affect male fertility under acute adult heat stress. We then tested these predictions by assessing the thermal sensitivity of fertility (TSF) in replicated lineages of seed beetles maintained for 68 generations under three alternative mating regimes manipulating the opportunity for sexual and natural selection. In line with the theoretical predictions, we find that males evolving under strong sexual selection suffer from increased TSF. Interestingly, females from the regime under strong sexual selection, who experienced relaxed selection on their own reproductive effort, had high fertility in benign settings but suffered increased TSF, like their brothers. This implies that female fertility and TSF evolved through genetic correlation with reproductive traits sexually selected in males. Paternal but not maternal heat stress reduced offspring fertility with no evidence for adaptive transgenerational plasticity among heat-exposed offspring, indicating that the observed effects may compound over generations. Our results suggest that trade-offs between fertility and traits increasing success in postcopulatory sexual selection can be revealed in harsh environments. This can put polyandrous species under immediate risk during extreme heat waves expected under future climate change.
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Affiliation(s)
- Julian Baur
- Department of Ecology and Genetics, Division of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Martyna Zwoinska
- Department of Ecology and Genetics, Division of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Mareike Koppik
- Department of Ecology and Genetics, Division of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Zoology, Animal Ecology, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Rhonda R Snook
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - David Berger
- Department of Ecology and Genetics, Division of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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2
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Abstract
In contrast to sexual selection on traits that affect interactions between the sexes before mating, little theoretical research has focused on the coevolution of postmating traits via cryptic female choice (when females bias fertilization toward specific males). We used simulation models to ask (a) whether and, if so, how nondirectional cryptic female choice (female-by-male interactions in fertilization success) causes deviations from models that focus exclusively on male-mediated postmating processes, and (b) how the risk of sperm competition, the strength of cryptic female choice, and tradeoffs between sperm number and sperm traits interact to influence the coevolutionary dynamics between cryptic female choice and sperm traits. We found that incorporating cryptic female choice can result in males investing much less in their ejaculates than predicted by models with sperm competition only. We also found that cryptic female choice resulted in the evolution of genetic correlations between cryptic female choice and sperm traits, even when the strength of cryptic female choice was weak, and the risk of sperm competition was low. This suggests that cryptic female choice may be important even in systems with low multiple mating. These genetic correlations increased with the risk of sperm competition and as the strength of cryptic female choice increased. When the strength of cryptic female choice and risk of sperm competition was high, extreme codivergence of sperm traits and cryptic female choice preference occurred even when the sperm trait traded off with sperm number. We also found that male traits lagged behind the evolution of female traits; this lag decreased with increasing strength of cryptic female choice and risk of sperm competition. Overall, our results suggest that cryptic female choice deserves more attention theoretically and may be driving trait evolution in ways just beginning to be explored.
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Affiliation(s)
- Matthew C Kustra
- Corresponding author: Department of Ecology and Evolutionary Biology Coastal Biology Building, 130 McAllister Way, University of California, Santa Cruz, CA 95060, United States.
| | - Suzanne H Alonzo
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95060, United States
- Institute of Marine Sciences, University of California, Santa Cruz, California 95060, USA
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3
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Brindle M, Ferguson-Gow H, Williamson J, Thomsen R, Sommer V. The evolution of masturbation is associated with postcopulatory selection and pathogen avoidance in primates. Proc Biol Sci 2023; 290:20230061. [PMID: 37282530 DOI: 10.1098/rspb.2023.0061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
Masturbation occurs throughout the animal kingdom. At first glance, however, the fitness benefits of this self-directed behaviour are unclear. Regardless, several drivers have been proposed. Non-functional hypotheses posit that masturbation is either a pathology, or a byproduct of high underlying sexual arousal, whereas functional hypotheses argue an adaptive benefit. The Postcopulatory Selection Hypothesis states that masturbation aids the chances of fertilization, while the Pathogen Avoidance Hypothesis states that masturbation helps reduce host infection by flushing pathogens from the genital tract. Here, we present comprehensive new data documenting masturbation across the primate order and use these, in conjunction with phylogenetic comparative methods, to reconstruct the evolutionary pathways and correlates of masturbation. We find that masturbation is an ancient trait within the primate order, becoming a more common aspect of the haplorrhine behavioural repertoire after the split from tarsiers. Our analyses provide support for both the Postcopulatory Selection and Pathogen Avoidance Hypotheses in male primates, suggesting that masturbation may be an adaptive trait, functioning at a macroevolutionary scale.
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Affiliation(s)
- Matilda Brindle
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
- The Institute of Zoology, Zoological Society of London, Regent's Park, London NW8 7LS, UK
| | - Henry Ferguson-Gow
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Joseph Williamson
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Ruth Thomsen
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Volker Sommer
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
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4
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Hadlow JH, Evans JP, Lymbery RA. Female reproductive fluids 'rescue' sperm from phenotypic ageing in an external fertilizer. Proc Biol Sci 2023; 290:20230574. [PMID: 37221848 DOI: 10.1098/rspb.2023.0574] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
Female reproductive fluids (FRFs) serve key reproductive functions in sexually reproducing animals, including modifying the way sperm swim and detect eggs, and influencing sperm lifespan. Despite the central role of FRF during fertilization, we know surprisingly little about sperm-FRF interactions under different environmental conditions. Theory suggests that in external fertilizers FRF may 'rescue' sperm from ageing effects as they search to fertilize eggs. Here, we test the interaction between these two fundamental properties of the fertilization environment, ejaculate age (i.e. time since ejaculation) and FRF, on a range of functional sperm phenotypes in a broadcast spawning mussel, Mytilus galloprovincialis. We found that the effects of ejaculate age on multivariate sperm motility traits and total sperm motility were altered by FRF, and that longer-lived sperm exhibit stronger, likely more advantageous, responses to FRF after periods of ageing. We also detected significant among-male variation in the relationship between sperm motility traits and ejaculate age; notably, these patterns were only revealed when sperm encountered FRF. Collectively these findings underscore the importance of considering female reproductive physiology when interpreting ageing-related declines in sperm motility, as doing so may expose importance sources of variation in sperm phenotypic plasticity among males and environments.
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Affiliation(s)
- Jessica H Hadlow
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley, WA, Australia
| | - Jonathan P Evans
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley, WA, Australia
| | - Rowan A Lymbery
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley, WA, Australia
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5
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Lipshutz SE, Torneo SJ, Rosvall KA. How Female-Female Competition Affects Male-Male Competition: Insights into Postcopulatory Sexual Selection from Socially Polyandrous Species. Am Nat 2023; 201:460-471. [PMID: 36848510 DOI: 10.1086/722799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractSexual selection is a major driver of trait variation, and the intensity of male competition for mating opportunities has been linked with sperm size across diverse taxa. Mating competition among females may also shape the evolution of sperm traits, but the effect of the interplay between female-female competition and male-male competition on sperm morphology is not well understood. We evaluated variation in sperm morphology in two species with socially polyandrous mating systems, in which females compete to mate with multiple males. Northern jacanas (Jacana spinosa) and wattled jacanas (J. jacana) vary in their degree of social polyandry and sexual dimorphism, suggesting species differences in the intensity of sexual selection. We compared mean and variance in sperm head, midpiece, and tail length between species and breeding stages because these measures have been associated with the intensity of sperm competition. We found that the species with greater polyandry, northern jacana, has sperm with longer midpieces and tails as well as marginally lower intraejaculate variation in tail length. Intraejaculate variation was also significantly lower in copulating males than in incubating males, suggesting flexibility in sperm production as males cycle between breeding stages. Our results indicate that stronger female-female competition for mating opportunities may also shape more intense male-male competition by selecting for longer and less variable sperm traits. These findings extend frameworks developed in socially monogamous species to reveal that sperm competition may be an important evolutionary force layered atop female-female competition for mates.
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6
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McKone MJ. Loss of Avian Intromittent Organs as a Sperm Competition Strategy: A Race to Be Last. Am Nat 2023; 201:138-153. [PMID: 36524937 DOI: 10.1086/722100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractThe loss of the intromittent organ (IO) in the majority of birds remains unexplained. Here, I propose that IO loss results from sperm competition in the context of the unique avian sperm storage system. The first stage of fertilization is the movement of sperm through the vagina from the site of ejaculation to the sperm storage tubules (SSTs) at the uterovaginal junction. In a second stage, sperm are released from the SSTs and move through the uterus to the site of fertilization in the infundibulum. Last-male fertilization precedence can occur if sperm that arrive later at the uterovaginal junction occupy uterus-side SSTs, which then have a head start in the race to the infundibulum with each ovulation. Under such "last-in, first-out" conditions, there is strong sperm competition to arrive later at the SSTs. Consequently, the optimal male strategy would be placement of the ejaculate at the cloacal opening to allow any other sperm in the vagina to reach the SSTs first. Cloacal placement is effectively achieved by loss of the IO. The evolution of altricial development in Neoaves, the largest clade that lacks IOs, created conditions that favor IO loss. Specifically, the smaller clutch sizes and hatching asynchrony of altricial birds increase the intensity of sperm competition for fertilization of early eggs in the laying sequence and thus the selective advantage of later arrival at the SSTs. The rarity of IO loss among all animals suggests that the complex mechanism of avian fertilization creates unique conditions for sperm competition.
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7
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Cramer ERA, Grønstøl G, Lifjeld JT. Flagellum tapering and midpiece volume in songbird spermatozoa. J Morphol 2022; 283:1577-1589. [PMID: 36260518 PMCID: PMC9828668 DOI: 10.1002/jmor.21524] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 01/19/2023]
Abstract
In contrast to numerous studies on spermatozoa length, relatively little work focuses on the width of spermatozoa, and particularly the width of the midpiece and flagellum. In flagellated spermatozoa, the flagellum provides forward thrust while energy may be provided via mitochondria in the midpiece and/or through glycolysis along the flagellum itself. Longer flagella may be able to provide greater thrust but may also require stronger structural features and more or larger mitochondria to supply sufficient energy. Here, we use scanning electron microscopy to investigate the ultrastructure of spermatozoa from 55 passerine species in 26 taxonomic families in the Passerides infraorder. Our data confirm the qualitative observation that the flagellum tapers along its length, and we show that longer flagella are wider at the neck. This pattern is similar to mammals, and likely reflects the need for longer cells to be stronger against shearing forces. We further estimate the volume of the mitochondrial helix and show that it correlates well with midpiece length, supporting the use of midpiece length as a proxy for mitochondrial volume, at least in between-species studies where midpiece length is highly variable. These results provide important context for understanding the evolutionary correlations among different sperm cell components and dimensions.
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8
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Chen DS, Clark AG, Wolfner MF. Octopaminergic/tyraminergic Tdc2 neurons regulate biased sperm usage in female Drosophila melanogaster. Genetics 2022; 221:6637517. [PMID: 35809068 PMCID: PMC9339280 DOI: 10.1093/genetics/iyac096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 06/07/2022] [Indexed: 02/07/2023] Open
Abstract
In polyandrous internally fertilizing species, a multiply-mated female can use stored sperm from different males in a biased manner to fertilize her eggs. The female's ability to assess sperm quality and compatibility is essential for her reproductive success, and represents an important aspect of postcopulatory sexual selection. In Drosophila melanogaster, previous studies demonstrated that the female nervous system plays an active role in influencing progeny paternity proportion, and suggested a role for octopaminergic/tyraminergic Tdc2 neurons in this process. Here, we report that inhibiting Tdc2 neuronal activity causes females to produce a higher-than-normal proportion of first-male progeny. This difference is not due to differences in sperm storage or release, but instead is attributable to the suppression of second-male sperm usage bias that normally occurs in control females. We further show that a subset of Tdc2 neurons innervating the female reproductive tract is largely responsible for the progeny proportion phenotype that is observed when Tdc2 neurons are inhibited globally. On the contrary, overactivation of Tdc2 neurons does not further affect sperm storage, release or progeny proportion. These results suggest that octopaminergic/tyraminergic signaling allows a multiply-mated female to bias sperm usage, and identify a new role for the female nervous system in postcopulatory sexual selection.
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Affiliation(s)
- Dawn S Chen
- Department of Molecular Biology and Genetics, Cornell University, Ithaca NY 14853, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca NY 14853, USA
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca NY 14853, USA
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9
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Chen DS, Clark AG, Wolfner MF. Octopaminergic/tyraminergic Tdc2 neurons regulate biased sperm usage in female Drosophila melanogaster. Genetics 2022; 221:6613932. [PMID: 35736370 DOI: 10.1093/genetics/iyac097] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/04/2022] [Indexed: 11/14/2022] Open
Abstract
In polyandrous internally fertilizing species, a multiply-mated female can use stored sperm from different males in a biased manner to fertilize her eggs. The female's ability to assess sperm quality and compatibility is essential for her reproductive success, and represents an important aspect of postcopulatory sexual selection. In Drosophila melanogaster, previous studies demonstrated that the female nervous system plays an active role in influencing progeny paternity proportion, and suggested a role for octopaminergic/tyraminergic Tdc2 neurons in this process. Here, we report that inhibiting Tdc2 neuronal activity causes females to produce a higher-than-normal proportion of first-male progeny. This difference is not due to differences in sperm storage or release, but instead is attributable to the suppression of second-male sperm usage bias that normally occurs in control females. We further show that a subset of Tdc2 neurons innervating the female reproductive tract is largely responsible for the progeny proportion phenotype that is observed when Tdc2 neurons are inhibited globally. On the contrary, overactivation of Tdc2 neurons does not further affect sperm storage and release or progeny proportion. These results suggest that octopaminergic/tyraminergic signaling allows a multiply-mated female to bias sperm usage, and identify a new role for the female nervous system in postcopulatory sexual selection.
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Affiliation(s)
- Dawn S Chen
- Department of Molecular Biology and Genetics, Cornell University, Ithaca NY 14853, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca NY 14853, USA
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca NY 14853, USA
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10
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Sorci G, Lesobre L, Vuarin P, Levêque G, Saint Jalme M, Lacroix F, Hingrat Y. Enforced monoandry over generations induces a reduction of female investment into reproduction in a promiscuous bird. Evol Appl 2021; 14:2773-2783. [PMID: 34950228 PMCID: PMC8674888 DOI: 10.1111/eva.13311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 11/20/2022] Open
Abstract
While uncovering the costs and benefits of polyandry has attracted considerable attention, assessing the net effect of sexual selection on population fitness requires the experimental manipulation of female mating over generations, which is usually only achievable in laboratory populations of arthropods. However, knowing if sexual selection improves or impairs the expression of life-history traits is key for the management of captive populations of endangered species, which are mostly long-lived birds and mammals. It might therefore be questionable to extrapolate the results gathered on laboratory populations of insects to infer the net effect of sexual selection on populations of endangered species. Here, we used a longitudinal dataset that has been collected on a long-lived bird, the houbara bustard, kept in a conservation breeding program, to investigate the effect of enforced monoandry on female investment into reproduction. In captivity, female houbara bustards are artificially inseminated with sperm collected from a single male (enforced monoandry), or sequentially inseminated with semen of different males (polyandry), allowing postcopulatory sexual selection to operate. We identified female lines that were produced either by monoandrous or polyandrous inseminations over three generations, and we compared reproductive investment of females from the two mating system groups. We found that females in the polyandrous lines had higher investment into reproduction as they laid more eggs per season and produced heavier hatchlings. Higher reproductive investment into reproduction in the polyandrous lines did not result from inherited differences from females initially included in the two mating system groups. These results show that removal of sexual selection can alter reproductive investment after only few generations, potentially hindering population fitness and the success of conservation breeding programs.
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Affiliation(s)
- Gabriele Sorci
- BiogéosciencesUMR 6282 CNRSUniversité de Bourgogne Franche‐ComtéDijonFrance
| | - Loïc Lesobre
- Reneco International Wildlife Consultants LLCAbu DhabiUnited Arab Emirates
| | - Pauline Vuarin
- BiogéosciencesUMR 6282 CNRSUniversité de Bourgogne Franche‐ComtéDijonFrance
- Reneco International Wildlife Consultants LLCAbu DhabiUnited Arab Emirates
- Present address:
Laboratoire de Biométrie et Biologie Evolutive ‐ UMR CNRS 5558Université Claude Bernard Lyon 116 rue Raphaël Dubois69622Villeurbanne CedexFrance
| | | | - Michel Saint Jalme
- Centre d’Ecologie et des Sciences de la ConservationUMR 7204 MNHN CNRS‐UPMCMuseum National d'Histoire NaturelleParisFrance
| | - Frédéric Lacroix
- Reneco International Wildlife Consultants LLCAbu DhabiUnited Arab Emirates
| | - Yves Hingrat
- Reneco International Wildlife Consultants LLCAbu DhabiUnited Arab Emirates
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11
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Syed ZA, Dallai R, Nasirzadeh N, Brill JA, O’Grady PM, Cong S, Leef EM, Rice S, Asif A, Nguyen S, Hansen MM, Dorus S, Pitnick S. Sperm Cyst "Looping": A Developmental Novelty Enabling Extreme Male Ornament Evolution. Cells 2021; 10:cells10102762. [PMID: 34685746 PMCID: PMC8534658 DOI: 10.3390/cells10102762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/12/2021] [Accepted: 10/12/2021] [Indexed: 01/20/2023] Open
Abstract
Postcopulatory sexual selection is credited as a principal force behind the rapid evolution of reproductive characters, often generating a pattern of correlated evolution between interacting, sex-specific traits. Because the female reproductive tract is the selective environment for sperm, one taxonomically widespread example of this pattern is the co-diversification of sperm length and female sperm-storage organ dimension. In Drosophila, having testes that are longer than the sperm they manufacture was believed to be a universal physiological constraint. Further, the energetic and time costs of developing long testes have been credited with underlying the steep evolutionary allometry of sperm length and constraining sperm length evolution in Drosophila. Here, we report on the discovery of a novel spermatogenic mechanism—sperm cyst looping—that enables males to produce relatively long sperm in short testis. This phenomenon (restricted to members of the saltans and willistoni species groups) begins early during spermatogenesis and is potentially attributable to heterochronic evolution, resulting in growth asynchrony between spermatid tails and the surrounding spermatid and somatic cyst cell membranes. By removing the allometric constraint on sperm length, this evolutionary innovation appears to have enabled males to evolve extremely long sperm for their body mass while evading delays in reproductive maturation time. On the other hand, sperm cyst looping was found to exact a cost by requiring greater total energetic investment in testes and a pronounced reduction in male lifespan. We speculate on the ecological selection pressures underlying the evolutionary origin and maintenance of this unique adaptation.
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Affiliation(s)
- Zeeshan A. Syed
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
- Correspondence: (Z.A.S.); (S.P.)
| | - Romano Dallai
- Department of Life Sciences, University of Siena, via Aldo Moro 2, 53100 Siena, Italy;
| | - Negar Nasirzadeh
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (N.N.); (J.A.B.)
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Julie A. Brill
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (N.N.); (J.A.B.)
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | | | - Siyuan Cong
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
| | - Ethan M. Leef
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
| | - Sarah Rice
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
| | - Amaar Asif
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
| | - Stephanie Nguyen
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
| | - Matthew M. Hansen
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
| | - Steve Dorus
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
| | - Scott Pitnick
- Center for Reproductive Evolution, Department of Biology, Syracuse University, Syracuse, NY 13244, USA; (S.C.); (E.M.L.); (S.R.); (A.A.); (S.N.); (M.M.H.); (S.D.)
- Correspondence: (Z.A.S.); (S.P.)
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12
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Patlar B, Jayaswal V, Ranz JM, Civetta A. Nonadaptive molecular evolution of seminal fluid proteins in Drosophila. Evolution 2021; 75:2102-2113. [PMID: 34184267 PMCID: PMC8457112 DOI: 10.1111/evo.14297] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/02/2021] [Accepted: 06/09/2021] [Indexed: 12/20/2022]
Abstract
Seminal fluid proteins (SFPs) are a group of reproductive proteins that are among the most evolutionarily divergent known. As SFPs can impact male and female fitness, these proteins have been proposed to evolve under postcopulatory sexual selection (PCSS). However, the fast change of the SFPs can also result from nonadaptive evolution, and the extent to which selective constraints prevent SFPs rapid evolution remains unknown. Using intra‐ and interspecific sequence information, along with genomics and functional data, we examine the molecular evolution of approximately 300 SFPs in Drosophila. We found that 50–57% of the SFP genes, depending on the population examined, are evolving under relaxed selection. Only 7–12% showed evidence of positive selection, with no evidence supporting other forms of PCSS, and 35–37% of the SFP genes were selectively constrained. Further, despite associations of positive selection with gene location on the X chromosome and protease activity, the analysis of additional genomic and functional features revealed their lack of influence on SFPs evolving under positive selection. Our results highlight a lack of sufficient evidence to claim that most SFPs are driven to evolve rapidly by PCSS while identifying genomic and functional attributes that influence different modes of SFPs evolution.
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Affiliation(s)
- Bahar Patlar
- Department of Biology, University of Winnipeg, Winnipeg, MB, R3B 2E9, Canada
| | - Vivek Jayaswal
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW, 2006, Australia
| | - José M Ranz
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, 92697
| | - Alberto Civetta
- Department of Biology, University of Winnipeg, Winnipeg, MB, R3B 2E9, Canada
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13
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De Nardo AN, Roy J, Sbilordo SH, Lüpold S. Condition-dependent interaction between mating success and competitive fertilization success in Drosophila melanogaster. Evolution 2021; 75:2014-2026. [PMID: 33834478 DOI: 10.1111/evo.14228] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/06/2021] [Accepted: 03/13/2021] [Indexed: 12/12/2022]
Abstract
Dietary restriction during development can affect adult body size and condition. In many species, larger (high-condition) males gain higher mating success through male-male competition and female choice, and female condition can affect the extent of both female mate choice and male investment in courtship or ejaculates. However, few studies have examined the joint effects and interplay of male and female condition during both the pre- and the postcopulatory phases of sexual selection. We therefore manipulated the larval diet of male and female Drosophila melanogaster to study how body size variation in both sexes biases competitive outcomes at different reproductive stages, from mating to paternity. We did not find a difference in mate preference or mating latency between females of different conditions, nor any interaction between male and female conditions. However, large males were more successful in gaining matings, but only when in direct competition, whereas mating latencies were shorter for low-condition males in noncompetitive settings. Small males also transferred more sperm to nonvirgin females, displaced a larger proportion of resident sperm, and achieved higher paternity shares per mating than large males. In agreement with existing theory, we suggest that small males might partially compensate for their low mating success by strategically investing in larger sperm numbers and potentially other, unmeasured ejaculate traits, when they do have a mating opportunity.
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Affiliation(s)
- Alessio N De Nardo
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
| | - Jeannine Roy
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
| | - Sonja H Sbilordo
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
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14
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Polak M, Hurtado-Gonzales JL, Benoit JB, Hooker KJ, Tyler F. Positive genetic covariance between male sexual ornamentation and fertilizing capacity. Curr Biol 2021; 31:1547-1554.e5. [PMID: 33567290 DOI: 10.1016/j.cub.2021.01.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/15/2020] [Accepted: 01/13/2021] [Indexed: 12/16/2022]
Abstract
Postcopulatory sexual selection results from variation in competitive fertilization success among males and comprises powerful evolutionary forces that operate after the onset of mating.1,2 Theoretical advances in the field of sexual selection addressing the buildup and coevolutionary consequences of genetic coupling3-5 motivate the hypothesis that indirect postcopulatory sexual selection may promote evolution of male secondary sexual traits-those traits traditionally ascribed to mate choice and male fighting.6,7 A crucial prediction of this hypothesis is genetic covariance between trait expression and competitive fertilization success, which has been predicted to arise, for example, when traits subject to pre- and postcopulatory sexual selection are under positive correlational selection.8 We imposed bidirectional artificial selection on male ornament (sex comb) size in Drosophila bipectinata and demonstrated increased competitive fertilization success as a correlated evolutionary response to increasing ornament size. Transcriptional analyses revealed that levels of specific seminal fluid proteins repeatedly shifted in response to this selection, suggesting that properties of the ejaculate, rather than the enlarged sex comb itself, contributed fertilizing capacity. We used ultraprecise laser surgery to reduce ornament size of high-line males and found that their fertilizing superiority persisted despite the size reduction, reinforcing the transcriptional results. The data support the existence of positive genetic covariance between a male secondary sexual trait and competitive fertilization success, and suggest the possibility that indirect postcopulatory sexual selection may, under certain conditions, magnify net selection on ornamental trait expression.
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Affiliation(s)
- Michal Polak
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA.
| | | | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA
| | - Kassie J Hooker
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA
| | - Frances Tyler
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA
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15
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Matsuzaki M, Hirohashi N, Tsudzuki M, Haqani MI, Maeda T, Mizushima S, Sasanami T. Longer and faster sperm exhibit better fertilization success in Japanese quail. Poult Sci 2021; 100:100980. [PMID: 33610899 PMCID: PMC7905478 DOI: 10.1016/j.psj.2021.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/18/2020] [Accepted: 01/01/2021] [Indexed: 11/06/2022] Open
Abstract
In birds, sperm storage tubules (SST) located in the utero-vaginal junction are thought to be a site of sperm selection; however, the exact mechanism of sperm selection is poorly understood. Here, we investigated sperm entry into the SST and subsequent fertilization success under a competitive situation created by artificial insemination of a sperm mixture obtained from 2 males. We employed 2 quail strains, a wild-type and a dominant black (DB) type, as this allows easy assessment of paternity by feather coloration. We found paternity of embryos was biased toward DB males when a sperm mix with similar sperm numbers from the 2 males strains was artificially inseminated into females. Our novel sperm staining method with 2 different fluorescent dyes showed that the DB-biased fertilization was because of the better ability of DB sperm to enter the SST. Moreover, we found that DB sperm had a longer flagellum and midpiece. These characteristics probably allow sperm to swim faster in a high viscosity medium, which may be a similar environment to the lumen of the female reproductive tract. Our results indicated that sperm competition occurs to win a place in the SST and that filling the SST with their own spermatozoa is a critical step to achieve better fertilization success for the male Japanese quail.
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Affiliation(s)
- Mei Matsuzaki
- Program of Food and AgriLife Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Noritaka Hirohashi
- Oki Marine Biological Station, Education and Research Center for Biological Resources, Faculty of Life and Environmental Science, Shimane University, Oki, Shimane 685-0024, Japan
| | - Masaoki Tsudzuki
- Laboratory of Animal Breeding and Genetics, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan; Japanese Avian Bioresource Project Research Center, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Mohammad Ibrahim Haqani
- Laboratory of Animal Breeding and Genetics, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Teruo Maeda
- Laboratory of Animal Reproduction, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan; Japanese Avian Bioresource Project Research Center, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Shusei Mizushima
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan; Japanese Avian Bioresource Project Research Center, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Tomohiro Sasanami
- Department of Applied Life Sciences, Faculty of Agriculture, Shizuoka University, Shizuoka City, Shizuoka 422-8529, Japan; Japanese Avian Bioresource Project Research Center, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan.
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16
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Garlovsky MD, Yusuf LH, Ritchie MG, Snook RR. Within-population sperm competition intensity does not predict asymmetry in conpopulation sperm precedence. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200071. [PMID: 33070721 PMCID: PMC7661444 DOI: 10.1098/rstb.2020.0071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Postcopulatory sexual selection can generate evolutionary arms races between the sexes resulting in the rapid coevolution of reproductive phenotypes. As traits affecting fertilization success diverge between populations, postmating prezygotic (PMPZ) barriers to gene flow may evolve. Conspecific sperm precedence is a form of PMPZ isolation thought to evolve early during speciation yet has mostly been studied between species. Here, we show conpopulation sperm precedence (CpSP) between Drosophila montana populations. Using Pool-seq genomic data we estimate divergence times and ask whether PMPZ isolation evolved in the face of gene flow. We find models incorporating gene flow fit the data best indicating populations experienced considerable gene flow during divergence. We find CpSP is asymmetric and mirrors asymmetry in non-competitive PMPZ isolation, suggesting these phenomena have a shared mechanism. However, we show asymmetry is unrelated to the strength of postcopulatory sexual selection acting within populations. We tested whether overlapping foreign and coevolved ejaculates within the female reproductive tract altered fertilization success but found no effect. Our results show that neither time since divergence nor sperm competitiveness predicts the strength of PMPZ isolation. We suggest that instead cryptic female choice or mutation-order divergence may drive divergence of postcopulatory phenotypes resulting in PMPZ isolation. This article is part of the theme issue ‘Fifty years of sperm competition’.
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Affiliation(s)
- Martin D Garlovsky
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Leeban H Yusuf
- Centre for Biological Diversity, University of St Andrews, St Andrews KY16 9TH, UK
| | - Michael G Ritchie
- Centre for Biological Diversity, University of St Andrews, St Andrews KY16 9TH, UK
| | - Rhonda R Snook
- Department of Zoology, Stockholm University, Stockholm 106-91, Sweden
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17
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Lüpold S, Reil JB, Manier MK, Zeender V, Belote JM, Pitnick S. How female × male and male × male interactions influence competitive fertilization in Drosophila melanogaster. Evol Lett 2020; 4:416-429. [PMID: 33014418 PMCID: PMC7523561 DOI: 10.1002/evl3.193] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/02/2020] [Accepted: 08/13/2020] [Indexed: 01/01/2023] Open
Abstract
How males and females contribute to joint reproductive success has been a long‐standing question in sexual selection. Under postcopulatory sexual selection, paternity success is predicted to derive from complex interactions among females engaging in cryptic female choice and males engaging in sperm competition. Such interactions have been identified as potential sources of genetic variation in sexually selected traits but are also expected to inhibit trait diversification. To date, studies of interactions between females and competing males have focused almost exclusively on genotypes and not phenotypic variation in sexually selected traits. Here, we characterize within‐ and between‐sex interactions in Drosophila melanogaster using isogenic lines with heritable variation in both male and female traits known to influence competitive fertilization. We confirmed, and expanded on, previously reported genotypic interactions within and between the sexes, and showed that several reproductive events, including sperm transfer, female sperm ejection, and sperm storage, were explained by two‐ and three‐way interactions among sex‐specific phenotypes. We also documented complex interactions between the lengths of competing males’ sperm and the female seminal receptacle, which are known to have experienced rapid female‐male co‐diversification. Our results highlight the nonindependence of sperm competition and cryptic female choice and demonstrate that complex interactions between the sexes do not limit the ability of multivariate systems to respond to directional sexual selection.
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Affiliation(s)
- Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich CH-8057 Switzerland.,Department of Biology Syracuse University Syracuse New York 13244
| | - Jonathan Bradley Reil
- Department of Entomology Cornell University Ithaca New York 14853.,Department of Plant and Environmental Protection Sciences University of Hawaii at Mānoa Honolulu Hawaii 96822
| | - Mollie K Manier
- Department of Biology Syracuse University Syracuse New York 13244.,Department of Biological Sciences George Washington University Washington DC 20052
| | - Valérian Zeender
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich CH-8057 Switzerland
| | - John M Belote
- Department of Biology Syracuse University Syracuse New York 13244
| | - Scott Pitnick
- Department of Biology Syracuse University Syracuse New York 13244
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18
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Abstract
Spermatozoa are the most morphologically diverse cell type, leading to the widespread assumption that they evolve rapidly. However, there is no direct evidence that sperm evolve faster than other male traits. Such a test requires comparing male traits that operate in the same selective environment, ideally produced from the same tissue, yet vary in function. Here, we examine rates of phenotypic evolution in sperm morphology using two insect groups where males produce fertile and non-fertile sperm types (Drosophila species from the obscura group and a subset of Lepidoptera species), where these constraints are solved. Moreover, in Drosophila we test the relationship between rates of sperm evolution and the link with the putative selective pressures of fertilization function and postcopulatory sexual selection exerted by female reproductive organs. We find repeated evolutionary patterns across these insect groups—lengths of fertile sperm evolve faster than non-fertile sperm. In Drosophila, fertile sperm length evolved faster than body size, but at the same rate as female reproductive organ length. We also compare rates of evolution of different sperm components, showing that head length evolves faster in fertile sperm while flagellum length evolves faster in non-fertile sperm. Our study provides direct evidence that sperm length evolves more rapidly in fertile sperm, probably because of their functional role in securing male fertility and in response to selection imposed by female reproductive organs.
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Affiliation(s)
- John L Fitzpatrick
- Department of Zoology, Stockholm University, Svante Arrhenius väg 18B, SE-10691, Sweden.,Faculty of Life Sciences, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK
| | - C Daisy Bridge
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK
| | - Rhonda R Snook
- Department of Zoology, Stockholm University, Svante Arrhenius väg 18B, SE-10691, Sweden
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19
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Dapper AL, Wade MJ. Relaxed Selection and the Rapid Evolution of Reproductive Genes. Trends Genet 2020; 36:640-649. [PMID: 32713599 DOI: 10.1016/j.tig.2020.06.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 10/23/2022]
Abstract
Evolutionary genomic studies find that reproductive protein genes, those directly involved in reproductive processes, diversify more rapidly than most other gene categories. Strong postcopulatory sexual selection acting within species is the predominant hypothesis proposed to account for the observed pattern. Recently, relaxed selection due to sex-specific gene expression has also been put forward to explain the relatively rapid diversification. We contend that relaxed selection due to sex-limited gene expression is the correct null model for tests of molecular evolution of reproductive genes and argue that it may play a more significant role in the evolutionary diversification of reproductive genes than previously recognized. We advocate for a re-evaluation of adaptive explanations for the rapid diversification of reproductive genes.
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Affiliation(s)
- Amy L Dapper
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA; Department of Biology, Indiana University, Bloomington, IN 47401, USA.
| | - Michael J Wade
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
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20
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Gómez RA, Maddison DR. Novelty and emergent patterns in sperm: Morphological diversity and evolution of spermatozoa and sperm conjugation in ground beetles (Coleoptera: Carabidae). J Morphol 2020; 281:862-892. [PMID: 32557896 DOI: 10.1002/jmor.21144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 04/30/2020] [Accepted: 05/03/2020] [Indexed: 12/15/2022]
Abstract
The beetle family Carabidae, with about 40,000 species, exhibits enough diversity in sperm structure and behavior to be an excellent model system for studying patterns and processes of evolution. We explore their potential, documenting sperm form in 177 species of ground beetles using light microscopy and collecting data on one qualitative and seven quantitative phenotypic traits. Our sampling captures 61% of the tribal-level diversity of ground beetles. These data highlight the notable morphological diversity of sperm in ground beetles and suggest that sperm in the group have dynamic evolutionary histories with much morphological innovation and convergence. Sperm vary among species in total length (48-3,400 μm), head length (0.5-270 μm), and head width (0.2-6.3 μm). Most ground beetles make sperm with heads that are indistinct from the flagella at the gross morphological level. However, some or all Omophron, Trachypachus, and Dyschiriini make broad-headed sperm that show morphological differences between species. Most ground beetles package their sperm into groups of sperm, termed conjugates, and ground beetles show variation in conjugate form and in the number and arrangement of sperm in a conjugate. Most ground beetles make sperm conjugates by embedding their sperm in a hyaline rod or spermatostyle. The spermatostyle is remarkably variable among species and varies in length from 17 to 41,000 μm. Several unrelated groups of ground beetles make only singleton sperm, including Nebriinae, Cicindelinae, many Trechinae, and the tribe Paussini. In order to study patterns in sperm evolution, we combine these data with a low-resolution phylogeny of ground beetles. Results from modern comparative analyses suggest the following: (a) sperm differ from conjugates in some aspect of their underlying evolutionary process, (b) sperm have influenced conjugate evolution and vice versa, and (c) conjugation with a spermatostyle likely evolved early within the history of Carabidae and it has been lost independently at least three times.
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Affiliation(s)
- R Antonio Gómez
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, USA
| | - David R Maddison
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, USA
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21
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Abstract
Sperm velocity is a key determinant of competitive fertilization success in many species. Selection is therefore expected to favour the evolution of faster sperm when the level of sperm competition is high. However, several aspects can determine the direction and strength of selection acting on this key performance trait, including ecological factors that influence both sperm competition and the strength of selection acting on correlated traits that may constrain evolutionary responses in sperm velocity. Here, we determine how a key ecological variable, the level of predation, shapes sperm swimming speed across 18 Trinidadian populations of guppies ( Poecilia reticulata). We use performance analysis, a statistical tool akin to the familiar methods of multivariate selection analyses, to determine how the level of predation influences sperm velocity (modelled as a performance trait) when accounting for correlated pre- and postcopulatory traits that are also impacted by predation. We show that predation affects the combination of pre- and postcopulatory traits that ultimately predict sperm performance. Overall, we report evidence for disruptive relationships between sperm performance and combinations of ornaments and sperm morphology, but the specific combinations of traits that predict sperm velocity depended on the level of predation. These analyses underscore the complex nonlinear interrelationships among pre- and postcopulatory traits and the importance of considering ecological factors that may ultimately change the way in which multiple traits interact to determine a trait's performance value. As such, our results are likely to be broadly applicable across systems where selection is influenced by ecological conditions.
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Affiliation(s)
- Alessandro Devigili
- 1 Department of Zoology, Stockholm University , Svante Arrhenius väg 18B, 10691 Stockholm , Sweden
| | - Jonathan P Evans
- 2 Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia , Crawley 6009, Western Australia , Australia
| | - John L Fitzpatrick
- 1 Department of Zoology, Stockholm University , Svante Arrhenius väg 18B, 10691 Stockholm , Sweden
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22
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Lenz TL, Hafer N, Samonte IE, Yeates SE, Milinski M. Cryptic haplotype-specific gamete selection yields offspring with optimal MHC immune genes. Evolution 2018; 72:2478-2490. [PMID: 30246285 PMCID: PMC6282957 DOI: 10.1111/evo.13591] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022]
Abstract
Females choose specific mates in order to produce fitter offspring. However, several factors interfere with females' control over fertilization of their eggs, including sneaker males and phenotypically unpredictable allele segregation during meiosis. Mate choice at the individual level thus provides only a poor approximation for obtaining the best genetic match. Consequently, postcopulatory sperm selection by female oocytes has been proposed as a mechanism to achieve complementary combinations of parental haplotypes. Here, using controlled in vitro fertilization of three‐spined stickleback eggs, we find haplotype‐specific fertilization bias toward gametes with complementary major histocompatibility complex (MHC) immunogenes. The resulting zygote (and thus offspring) genotypes exhibit an intermediate level of individual MHC diversity that was previously shown to confer highest pathogen resistance. Our finding of haplotype‐specific gamete selection thus represents an intriguing mechanism for fine‐tuned optimization of the offspring's immune gene composition and an evolutionary advantage in the Red Queen dynamics of host‐parasite coevolution.
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Affiliation(s)
- Tobias L Lenz
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Nina Hafer
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Irene E Samonte
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Sarah E Yeates
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany.,Current Address: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Manfred Milinski
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
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23
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Loo J, Kennington WJ, de Lestang S, How J, Evans JP. High levels of polyandry, but limited evidence for multiple paternity, in wild populations of the western rock lobster ( Panulirus cygnus). Ecol Evol 2018; 8:4525-4533. [PMID: 29760893 PMCID: PMC5938460 DOI: 10.1002/ece3.3985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 02/07/2018] [Accepted: 02/09/2018] [Indexed: 01/01/2023] Open
Abstract
Polyandry, where multiple mating by females results in the temporal and spatial overlap of ejaculates from two or more males, is taxonomically widespread and occurs in varying frequencies within and among species. In decapods (crabs, lobsters, crayfish, and prawns), rates of polyandry are likely to be variable, but the extent to which patterns of multiple paternity reflect multiple mating, and thus are shaped by postmating processes that bias fertilization toward one or a subset of mated males, is unclear. Here, we use microsatellite markers to examine the frequency of multiple mating (the presence of spermatophores from two or more males) and patterns of paternity in wild populations of western rock lobster (Panulirus cygnus). Our data confirm that >45% of females had attached spermatophores arising from at least two males (i.e., confirming polyandry), but we found very limited evidence for multiple paternity; among 24 clutches sampled in this study, only two arose from fertilizations by two or more males. Single inferred paternal genotypes accounted for all remaining progeny genotypes in each clutch, including several instances when the mother had been shown to mate with two or more males. These findings highlight the need for further work to understand whether polyandry is adaptive and to uncover the mechanisms underlying postmating paternity biases in this system.
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Affiliation(s)
- Jacqueline Loo
- Centre for Evolutionary Biology School of Biological Sciences The University of Western Australia Crawley WA Australia
| | - Winn Jason Kennington
- Centre for Evolutionary Biology School of Biological Sciences The University of Western Australia Crawley WA Australia
| | - Simon de Lestang
- Western Australian Fisheries and Marine Research Laboratories North Beach WA Australia
| | - Jason How
- Western Australian Fisheries and Marine Research Laboratories North Beach WA Australia
| | - Jonathan P Evans
- Centre for Evolutionary Biology School of Biological Sciences The University of Western Australia Crawley WA Australia
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24
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McCullough EL, Buzatto BA, Simmons LW. Benefits of polyandry: Molecular evidence from field-caught dung beetles. Mol Ecol 2017; 26:3546-3555. [PMID: 28370584 DOI: 10.1111/mec.14127] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 03/07/2017] [Accepted: 03/21/2017] [Indexed: 11/29/2022]
Abstract
When females mate with multiple males, they set the stage for postcopulatory sexual selection via sperm competition and/or cryptic female choice. Surprisingly little is known about the rates of multiple mating by females in the wild, despite the importance of this information in understanding the potential for postcopulatory sexual selection to drive the evolution of reproductive behaviour, morphology and physiology. Dung beetles in the genus Onthophagus have become a laboratory model for studying pre- and postcopulatory sexual selection, yet we still lack information about the reproductive behaviour of female dung beetles in natural populations. Here, we develop microsatellite markers for Onthophagus taurus and use them to genotype the offspring of wild-caught females and to estimate natural rates of multiple mating and patterns of sperm utilization. We found that O. taurus females are highly polyandrous: 88% of females produced clutches sired by at least two males, and 5% produced clutches with as many as five sires. Several females (23%) produced clutches with significant paternity skew, indicating the potential for strong postcopulatory sexual selection in natural populations. There were also strong positive correlations between the number of offspring produced and both number of fathers and paternity skew, which suggests that females benefit from mating polyandrously by inciting postcopulatory mechanisms that bias paternity towards males that can sire more viable offspring. This study evaluates the fitness consequences of polyandry for an insect in the wild and provides strong evidence that female dung beetles benefit from multiple mating under natural conditions.
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Affiliation(s)
- Erin L McCullough
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, Western Australia, Australia
| | - Bruno A Buzatto
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, Western Australia, Australia
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, Western Australia, Australia
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25
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Zajitschek F, Zajitschek S, Manier M. Paternal diet affects differential gene expression, but not sperm competition, in sons. Biol Lett 2017; 13:rsbl.2016.0914. [PMID: 28202685 PMCID: PMC5326516 DOI: 10.1098/rsbl.2016.0914] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 01/20/2017] [Indexed: 12/17/2022] Open
Abstract
Parental environment can widely influence offspring phenotype, but paternal effects in the absence of parental care remain poorly understood. We asked if protein content in the larval diet of fathers affected paternity success and gene expression in their sons. We found that males reared on high-protein diet had sons that fared better during sperm competition, suggesting that postcopulatory sexual selection is subject to transgenerational paternal effects. Moreover, immune response genes were downregulated in sons of low-protein fathers, while genes involved in metabolic and reproductive processes were upregulated.
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Affiliation(s)
- Felix Zajitschek
- Department of Biological Sciences, George Washington University, Washington, DC, USA.,School of Biological Sciences, Monash University, Melbourne, Australia
| | - Susanne Zajitschek
- Department of Biological Sciences, George Washington University, Washington, DC, USA.,School of Biological Sciences, Monash University, Melbourne, Australia.,Doñana Biological Station, EBD-CSIC, Seville, Spain
| | - Mollie Manier
- Department of Biological Sciences, George Washington University, Washington, DC, USA
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26
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Abstract
The extreme morphological variability of the baculum across mammals is thought to be the result of sexual selection (particularly, high levels of postcopulatory selection). However, the evolutionary trajectory of the mammalian baculum is little studied and evidence for the adaptive function of the baculum has so far been elusive. Here, we use Markov chain Monte Carlo methods implemented in a Bayesian phylogenetic framework to reconstruct baculum evolution across the mammalian class and investigate the rate of baculum length evolution within the primate order. We then test the effects of testes mass (postcopulatory sexual selection), polygamy, seasonal breeding and intromission duration on the baculum in primates and carnivores. The ancestral mammal did not have a baculum, but both ancestral primates and carnivores did. No relationship was found between testes mass and baculum length in either primates or carnivores. Intromission duration correlated with baculum presence over the course of primate evolution, and prolonged intromission predicts significantly longer bacula in extant primates and carnivores. Both polygamous and seasonal breeding systems predict significantly longer bacula in primates. These results suggest the baculum plays an important role in facilitating reproductive strategies in populations with high levels of postcopulatory sexual selection.
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Affiliation(s)
- Matilda Brindle
- Department of Anthropology, University College London, 14 Taviton Street, London, WC1H 0BW, UK
| | - Christopher Opie
- Department of Anthropology, University College London, 14 Taviton Street, London, WC1H 0BW, UK
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27
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Buzatto BA, Thyer EM, Roberts JD, Simmons LW. Sperm competition and the evolution of precopulatory weapons: Testis size and amplexus position, but not arm strength, affect fertilization success in a chorusing frog. Evolution 2016; 71:329-341. [PMID: 27911018 DOI: 10.1111/evo.13136] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/31/2016] [Accepted: 11/11/2016] [Indexed: 02/05/2023]
Abstract
Trade-offs between pre- and postcopulatory traits influence their evolution, and male expenditure on such traits is predicted to depend on the number of competitors, the benefits from investing in weapons, and the risk and intensity of sperm competition. Males of the chorusing frog Crinia georgiana use their arms as weapons in contest competition. Previously, we showed that increased numbers of rivals elevated the risk and intensity of sperm competition due to multimale amplexus, and caused a reversal in the direction of precopulatory selection on arm girth. Here, we focused on the factors affecting postcopulatory fertilization success during group spawning, using paternity data from natural choruses. Competitive fertilization success depended on the time spent amplexed and amplexus position. Relative testes size but not arm girth, contributed to fertilization success, but the effect of testes size depended on amplexus position. Our findings offer within species empirical support for recent sperm competition models that incorporate precopulatory male-male competition, and show why an understanding of the evolution of animal weapons requires a consideration of both pre- and postcopulatory episodes of sexual selection.
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Affiliation(s)
- Bruno A Buzatto
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, 6009, WA, Australia
| | - Evan M Thyer
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, 6009, WA, Australia
| | - J Dale Roberts
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, 6009, WA, Australia.,Centre of Excellence in Natural Resource Management, The University of Western Australia, Albany, 6332, WA, Australia
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, 6009, WA, Australia
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28
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Sato N, Yoshida MA, Kasugai T. Impact of cryptic female choice on insemination success: Larger sized and longer copulating male squid ejaculate more, but females influence insemination success by removing spermatangia. Evolution 2016; 71:111-120. [PMID: 27805265 DOI: 10.1111/evo.13108] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 10/12/2016] [Accepted: 10/21/2016] [Indexed: 11/28/2022]
Abstract
In polyandrous mating systems, sperm competition and cryptic female choice (CFC) are well recognized as postcopulatory evolutionary forces. However, it remains challenging to separate CFC from sperm competition and to estimate how much CFC influences insemination success because those processes usually occur inside the female's body. The Japanese pygmy squid, Idiosepius paradoxus, is an ideal species in which to separate CFC from sperm competition because sperm transfer by the male and sperm displacement by the female can be observed directly at an external location on the female's body. Here, we counted the number of spermatangia transferred to, removed from, and remaining on the female body during single copulation episodes. We measured behavioral and morphological characteristics of the male, such as duration of copulation and body size. Although males with larger body size and longer copulation time were capable of transferring larger amounts of sperm, females preferentially eliminated sperm from males with larger body size and shorter copulation time by spermatangia removal; thus, CFC could attenuate sperm precedence by larger males, whereas it reinforces sperm precedence by males with longer copulation time. Genetic paternity analysis revealed that fertilisation success for each male was correlated with remaining sperm volume that is adjusted by females after copulation.
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Affiliation(s)
- Noriyosi Sato
- Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Nagasaki, Nagasaki, Japan.,Current Address: Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, United Kingdom
| | - Masa-Aki Yoshida
- Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka, Japan.,Current Address: Marine Biological Science Section, Education and Research Center for Biological Resources, Faculty of Life and Environmental Science, Shimane University, Kamo 194, Okinoshima-cho, Oki, Shimane, Japan
| | - Takashi Kasugai
- Port of Nagoya Public Aquarium, 1-3 Minato-machi, Minato-ku, Nagoya, Aichi, Japan
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29
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Abstract
Postcopulatory sexual selection is widely accepted to underlie the extraordinary diversification of sperm morphology. However, why does it favour longer sperm in some taxa but shorter in others? Two recent hypotheses addressing this discrepancy offered contradictory explanations. Under the sperm dilution hypothesis, selection via sperm density in the female reproductive tract favours more but smaller sperm in large, but the reverse in small, species. Conversely, the metabolic constraint hypothesis maintains that ejaculates respond positively to selection in small endothermic animals with high metabolic rates, whereas low metabolic rates constrain their evolution in large species. Here, we resolve this debate by capitalizing on the substantial variation in mammalian body size and reproductive physiology. Evolutionary responses shifted from sperm length to number with increasing mammalian body size, thus supporting the sperm dilution hypothesis. Our findings demonstrate that body-size-mediated trade-offs between sperm size and number can explain the extreme diversification in sperm phenotypes.
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Affiliation(s)
- Stefan Lüpold
- Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - John L Fitzpatrick
- Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
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30
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Hirohashi N, Tamura-Nakano M, Nakaya F, Iida T, Iwata Y. Sneaker Male Squid Produce Long-lived Spermatozoa by Modulating Their Energy Metabolism. J Biol Chem 2016; 291:19324-34. [PMID: 27385589 DOI: 10.1074/jbc.m116.737494] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Indexed: 01/16/2023] Open
Abstract
Spermatozoa released by males should remain viable until fertilization. Hence, sperm longevity is governed by intrinsic and environmental factors in accordance with the male mating strategy. However, whether intraspecific variation of insemination modes can impact sperm longevity remains to be elucidated. In the squid Heterololigo bleekeri, male dimorphism (consort and sneaker) is linked to two discontinuous insemination modes that differ in place and time. Notably, only sneaker male spermatozoa inseminated long before egg spawning can be stored in the seminal receptacle. We found that sneaker spermatozoa exhibited greater persistence in fertilization competence and flagellar motility than consort ones because of a larger amount of flagellar glycogen. Sneaker spermatozoa also showed higher capacities in glucose uptake and lactate efflux. Lactic acidosis was considered to stabilize CO2-triggered self-clustering of sneaker spermatozoa, thus establishing hypoxia-induced metabolic changes and sperm survival. These results, together with comparative omics analyses, suggest that postcopulatory reproductive contexts define sperm longevity by modulating the inherent energy levels and metabolic pathways.
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Affiliation(s)
- Noritaka Hirohashi
- From the Oki Marine Biological Station, Education and Research Center for Biological Resources, Shimane University, Oki 685-0024, Japan,
| | - Miwa Tamura-Nakano
- the Research Institute, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
| | - Fumio Nakaya
- the Center for Science Education, Osaka Kyoiku University, Osaka 582-858, Japan, and
| | - Tomohiro Iida
- From the Oki Marine Biological Station, Education and Research Center for Biological Resources, Shimane University, Oki 685-0024, Japan
| | - Yoko Iwata
- the Atmosphere and Ocean Research Institute, University of Tokyo, Chiba 277-8564, Japan
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31
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Ala-Honkola O, Ritchie MG, Veltsos P. Postmating-prezygotic isolation between two allopatric populations of Drosophila montana: fertilisation success differs under sperm competition. Ecol Evol 2016; 6:1679-91. [PMID: 27087932 PMCID: PMC4801965 DOI: 10.1002/ece3.1995] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/17/2016] [Accepted: 01/18/2016] [Indexed: 12/23/2022] Open
Abstract
Postmating but prezygotic (PMPZ) interactions are increasingly recognized as a potentially important early‐stage barrier in the evolution of reproductive isolation. A recent study described a potential example between populations of the same species: single matings between Drosophila montana populations resulted in differential fertilisation success because of the inability of sperm from one population (Vancouver) to penetrate the eggs of the other population (Colorado). As the natural mating system of D. montana is polyandrous (females remate rapidly), we set up double matings of all possible crosses between the same populations to test whether competitive effects between ejaculates influence this PMPZ isolation. We measured premating isolation in no‐choice tests, female fecundity, fertility and egg‐to‐adult viability after single and double matings as well as second‐male paternity success (P2). Surprisingly, we found no PMPZ reproductive isolation between the two populations under a competitive setting, indicating no difficulty of sperm from Vancouver males to fertilize Colorado eggs after double matings. While there were subtle differences in how P2 changed over time, suggesting that Vancouver males’ sperm are somewhat less competitive in a first‐male role within Colorado females, these effects did not translate into differences in overall P2. Fertilisation success can thus differ dramatically between competitive and noncompetitive conditions, perhaps because the males that mate second produce higher quality ejaculates in response to sperm competition. We suggest that unlike in more divergent species comparisons, where sperm competition typically increases reproductive isolation, ejaculate tailoring can reduce the potential for PMPZ isolation when recently diverged populations interbreed.
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Affiliation(s)
- Outi Ala-Honkola
- Department of Biological and Environmental Science University of Jyvaskyla PO Box 35 FI- 40014 Jyvaskyla Finland
| | - Michael G Ritchie
- Centre for Biological Diversity School of Biology University of St Andrews St Andrews KY16 9TS UK
| | - Paris Veltsos
- Department of Ecology and Evolution University of Lausanne Biophore Building Lausanne 1015 Switzerland
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32
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Abstract
Sperm senescence can have important evolutionary implications due to its deleterious effects on sperm quality and offspring performance. Consequently, it has been argued that polyandry (female multiple mating) may facilitate the selection of younger, and therefore competitively superior, sperm when ejaculates from multiple males compete for fertilization. Surprisingly, however, unequivocal evidence that sperm ageing influences traits that underlie sperm competitiveness is lacking. Here, we used a paired experimental design that compares sperm quality between 'old' and 'young' ejaculates from individual male guppies (Poecilia reticulata). We show that older sperm exhibit significant reductions in sperm velocity compared with younger sperm from the same males. We found no evidence that the brightness of the male's orange (carotenoid) spots, which are thought to signal resistance to oxidative stress (and thus age-related declines in sperm fitness), signals a male's ability to withstand the deleterious effects of sperm ageing. Instead, polyandry may be a more effective strategy for females to minimize the likelihood of being fertilized by aged sperm.
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Affiliation(s)
- Clelia Gasparini
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Jennifer L Kelley
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Jonathan P Evans
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
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33
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Abstract
I propose that the underlying adaptation enabling the reproductive strategy of birthing live young (viviparity) is retraction of the site of fertilization within the female reproductive tract, and that this evolved as a means of postcopulatory sexual selection. There are three conspicuous aspects associated with viviparity: (i) internal development is a complex trait often accompanied by a suite of secondary adaptations, yet it is unclear how the intermediate state of this trait - egg retention - could have evolved; (ii) viviparity often results in a reduction in fecundity; (iii) viviparity has evolved independently many times across a diverse array of animal groups. Focusing on the Diptera (true flies), I provide explanations for these observations. I further propose that fecundity is not traded-off to enable potential benefits of viviparity, but rather that loss of fecundity is directly selected and egg retention is an indirect consequence - a model that provides a unifying common basis for the ubiquity of viviparity.
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Affiliation(s)
- Alex T Kalinka
- Institute of Population genetics, Vetmeduni, Vienna, Austria
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34
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Orr TJ, Brennan PLR. Sperm storage: distinguishing selective processes and evaluating criteria. Trends Ecol Evol 2015; 30:261-72. [PMID: 25843274 DOI: 10.1016/j.tree.2015.03.006] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/05/2015] [Accepted: 03/06/2015] [Indexed: 01/18/2023]
Abstract
Sperm storage, the extended maintenance of viable sperm, probably occurs in most internally fertilizing animals. Because it temporally separates mating from conception, sperm storage can be adaptive in ecologically diverse habitats and affect life histories, mating systems, cryptic female choice, sperm competition, and sexual conflict. Sperm storage can result from different selective forces acting on females and/or males, sometimes resulting in coevolution. The various criteria often used to determine the presence of sperm storage in any given taxon can result from the action of any one or all of these selective forces. Here we discuss the criteria used to study sperm storage and how we can use these to better understand the evolution of diversity in sperm-storage adaptations.
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Affiliation(s)
- Teri J Orr
- Departments of Psychology and Biology, and Organismic and Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA.
| | - Patricia L R Brennan
- Departments of Psychology and Biology, and Organismic and Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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35
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Rose EG, Brand CL, Wilkinson GS. Rapid evolution of asymmetric reproductive incompatibilities in stalk-eyed flies. Evolution 2013; 68:384-96. [PMID: 24171729 DOI: 10.1111/evo.12307] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/22/2013] [Indexed: 12/22/2022]
Abstract
The steps by which isolated populations acquire reproductive incompatibilities remain poorly understood. One potentially important process is postcopulatory sexual selection because it can generate divergence between populations in traits that influence fertilization success after copulation. Here we present a comprehensive analysis of this form of reproductive isolation by conducting reciprocal crosses between variably diverged populations of stalk-eyed flies (Teleopsis dalmanni). First, we measure seven types of reproductive incompatibility between copulation and fertilization. We then compare fertilization success to hatching success to quantify hybrid inviability. Finally, we determine if sperm competition acts to reinforce or counteract any incompatibilities. We find evidence for multiple incompatibilities in most crosses, including failure to store sperm after mating, failure of sperm to reach the site of fertilization, failure of sperm to fertilize eggs, and failure of embryos to develop. Local sperm have precedence over foreign sperm, but this effect is due mainly to differences in sperm transfer and reduced hatching success. Crosses between recently diverged populations are asymmetrical with regard to the degree and type of incompatibility. Because sexual conflict in these flies is low, postcopulatory sexual selection, rather than antagonistic coevolution, likely causes incompatibilities due to mismatches between male and female reproductive traits.
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Affiliation(s)
- Emily G Rose
- Department of Biology, University of Maryland, College Park, Maryland, 20742
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36
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Løvlie H, Gillingham MAF, Worley K, Pizzari T, Richardson DS. Cryptic female choice favours sperm from major histocompatibility complex-dissimilar males. Proc Biol Sci 2013; 280:20131296. [PMID: 24004935 PMCID: PMC3768299 DOI: 10.1098/rspb.2013.1296] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cryptic female choice may enable polyandrous females to avoid inbreeding or bias offspring variability at key loci after mating. However, the role of these genetic benefits in cryptic female choice remains poorly understood. Female red junglefowl, Gallus gallus, bias sperm use in favour of unrelated males. Here, we experimentally investigate whether this bias is driven by relatedness per se, or by similarity at the major histocompatibility complex (MHC), genes central to vertebrate acquired immunity, where polymorphism is critical to an individual's ability to combat pathogens. Through experimentally controlled natural matings, we confirm that selection against related males' sperm occurs within the female reproductive tract but demonstrate that this is more accurately predicted by MHC similarity: controlling for relatedness per se, more sperm reached the eggs when partners were MHC-dissimilar. Importantly, this effect appeared largely owing to similarity at a single MHC locus (class I minor). Further, the effect of MHC similarity was lost following artificial insemination, suggesting that male phenotypic cues might be required for females to select sperm differentially. These results indicate that postmating mechanisms that reduce inbreeding may do so as a consequence of more specific strategies of cryptic female choice promoting MHC diversity in offspring.
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Affiliation(s)
- Hanne Løvlie
- Department of Zoology, Edward Grey Institute, University of Oxford, Oxford OX1 3PS, UK.
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37
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Kehl T, Karl I, Fischer K. Old-male paternity advantage is a function of accumulating sperm and last-male precedence in a butterfly. Mol Ecol 2013; 22:4289-4297. [PMID: 23889582 DOI: 10.1111/mec.12386] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/08/2013] [Accepted: 05/09/2013] [Indexed: 12/01/2022]
Abstract
Old-male mating advantage has been convincingly demonstrated in Bicyclus anynana butterflies. This intriguing pattern may be explained by two alternative hypotheses: (i) an increased aggressiveness and persistence of older males during courtship, being caused by the older males' low residual reproductive value; and (ii) an active preference of females towards older males what reflects a good genes hypothesis. Against this background, we here investigate postcopulatory sexual selection by double-mating Bicyclus anynana females to older and younger males, thus allowing for sperm competition and cryptic mate choice, and by genotyping the resulting offspring. Virgin females were mated with a younger virgin (2-3 days old) and afterwards an older virgin male (12-13 days old) or vice versa. Older males had a higher paternity success than younger ones, but only when being the second (=last) mating partner, while paternity success was equal among older and younger males when older males were the first mating partner. Older males produced larger spermatophores with much higher numbers of fertile sperm than younger males. Thus, we found no evidence for cryptic female mate choice. Rather, the findings reported here seem to result from a combination of last-male precedence and the number of sperm transferred upon mating, both increasing paternity success.
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Affiliation(s)
- Tobias Kehl
- Zoological Institute & Museum, Johann-Sebastian-Bach Str. 11/12, 17489, Greifswald, Germany
| | - Isabell Karl
- Zoological Institute & Museum, Johann-Sebastian-Bach Str. 11/12, 17489, Greifswald, Germany
| | - Klaus Fischer
- Zoological Institute & Museum, Johann-Sebastian-Bach Str. 11/12, 17489, Greifswald, Germany
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38
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Manier MK, Belote JM, Berben KS, Lüpold S, Ala-Honkola O, Collins WF, Pitnick S. Rapid diversification of sperm precedence traits and processes among three sibling Drosophila species. Evolution 2013; 67:2348-62. [PMID: 23888856 DOI: 10.1111/evo.12117] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/12/2013] [Indexed: 01/13/2023]
Abstract
Postcopulatory sexual selection is credited with driving rapid evolutionary diversification of reproductive traits and the formation of reproductive isolating barriers between species. This judgment, however, has largely been inferred rather than demonstrated due to general lack of knowledge about processes and traits underlying variation in competitive fertilization success. Here, we resolved processes determining sperm fate in twice-mated females, using transgenic Drosophila simulans and Drosophila mauritiana populations with fluorescently labeled sperm heads. Comparisons among these two species and Drosophila melanogaster revealed a shared motif in the mechanisms of sperm precedence, with postcopulatory sexual selection potentially occurring during any of the three discrete stages: (1) insemination; (2) sperm storage; and (3) sperm use for fertilization, and involving four distinct phenomena: (1) sperm transfer; (2) sperm displacement; (3) sperm ejection; and (4) sperm selection for fertilizations. Yet, underlying the qualitative similarities were significant quantitative differences in nearly every relevant character and process. We evaluate these species differences in light of concurrent investigations of within-population variation in competitive fertilization success and postmating/prezygotic reproductive isolation in hybrid matings between species to forge an understanding of the relationship between microevolutionary processes and macroevolutionary patterns as pertains to postcopulatory sexual selection in this group.
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Affiliation(s)
- Mollie K Manier
- Department of Biology, Syracuse University, Syracuse, New York 13244, USA
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39
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Lüpold S. Ejaculate quality and constraints in relation to sperm competition levels among eutherian mammals. Evolution 2013; 67:3052-60. [PMID: 24094354 DOI: 10.1111/evo.12132] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 04/05/2013] [Indexed: 01/21/2023]
Abstract
The outcome of sperm competition is influenced by the relative quantity and quality of sperm among competing ejaculates. Whereas it is well established that individual ejaculate traits evolve rapidly under postcopulatory sexual selection, little is known about other factors that might influence the evolution of ejaculates. For example, the metabolic rate is likely to affect the sperm production rate and the cellular activity or metabolism of sperm, and it has recently been suggested to constrain the evolution of sperm length in large but not small mammals. I thus examined in eutherian mammals how ejaculate quality traits vary with one another and with testis mass, body size, and metabolism. I found all ejaculate traits to covary positively with one another and to increase with relative testis mass. When controlling for testis mass, small-bodied species showed superior sperm quality (but not sperm number). Furthermore, sperm motility and viability were positively associated with the mass-corrected metabolic rate, but the percentage of morphologically normal and acrosome-intact sperm were not. These results indicate that body size and the energy budget may also influence the evolution of ejaculate quality, although these influences appear to vary among traits.
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Affiliation(s)
- Stefan Lüpold
- Department of Biology, Life Sciences Complex, 107 College Place, Syracuse University, Syracuse, New York, 13244.
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40
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Abstract
Sperm display remarkable morphological diversity among even closely related species, a pattern that is widely attributed to postcopulatory sexual selection. Surprisingly few studies have used phylogenetic analyses to discern the details of evolutionary diversification in ornaments and armaments subject to sexual selection, and the origins of novel sperm traits and their subsequent modification are particularly poorly understood. Here we investigate sperm evolution in diving beetles (Dytiscidae), revealing dramatic diversification in flagellum length, head shape, presence of sperm heteromorphism, and the presence/type of sperm conjugation, an unusual trait where two or more sperm unite for motility or transport. Sperm conjugation was found to be the ancestral condition in diving beetles, with subsequent diversification into three forms, each exhibiting varying degrees of evolutionary loss, convergence, and recurrence. Sperm head shape, but not length or heteromorphism, was found to evolve in a significantly correlated manner with conjugation, consistent with the different mechanisms of head alignment and binding required for the different forms of conjugation. Our study reveals that sperm morphological evolution is channeled along particular evolutionary pathways (i.e., conjugate form), yet subject to considerable diversification within those pathways through modification in sperm length, head shape, and heteromorphism.
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Affiliation(s)
- Dawn M. Higginson
- Department of Biology, Syracuse University, Syracuse, New York 13244
| | - Kelly B. Miller
- Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131
| | - Kari A. Segraves
- Department of Biology, Syracuse University, Syracuse, New York 13244
| | - Scott Pitnick
- Department of Biology, Syracuse University, Syracuse, New York 13244
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