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Chung MHJ, Mahmud-Al-Hasan M, Jennions MD, Head ML. Effects of inbreeding and elevated rearing temperatures on strategic sperm investment. Behav Ecol 2024; 35:arae044. [PMID: 38903732 PMCID: PMC11187721 DOI: 10.1093/beheco/arae044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/24/2024] [Accepted: 06/04/2024] [Indexed: 06/22/2024] Open
Abstract
Males often strategically adjust the number of available sperm based on the social context (i.e. sperm priming response), but it remains unclear how environmental and genetic factors shape this adjustment. In freshwater ecosystems, high ambient temperatures often lead to isolated pools of hotter water in which inbreeding occurs. Higher water temperatures and inbreeding can impair fish development, potentially disrupting sperm production. We used guppies (Poecilia reticulata) to investigate how developmental temperature (26 °C, 30 °C) and male inbreeding status (inbred, outbred) influence their sperm priming response. We also tested if sperm priming was affected by whether the female was a relative (sister) and whether she was inbred or outbred. There was no effect of rearing temperature; male inbreeding status alone determined the number of available sperm in response to female presence, her inbreeding status, and her relatedness. Inbred males produced significantly more sperm in the presence of an unrelated, outbred female than when no female was present. Conversely, outbred males did not alter the number of sperm available in response to female presence or relatedness. Moreover, inbred males produced marginally more sperm when exposed to an unrelated female that was outbred rather than inbred, but there was no difference when exposed to an inbred female that was unrelated versus related. Together, a sperm priming response was only observed in inbred males when exposed to an outbred female. Outbred females in our study were larger than inbred females, suggesting that inbred males strategically allocated ejaculate resources toward females in better condition.
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Affiliation(s)
- Meng-Han Joseph Chung
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Md Mahmud-Al-Hasan
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Michael D Jennions
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
- Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Centre, Stellenbosch University, Stellenbosch 7600, South Africa
| | - Megan L Head
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
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2
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Liu J, He XZ, Wang Q. Male larval experience of cues from adult rivals alters lifetime sperm investment patterns in a sperm heteromorphic moth, Ephestia kuehniella. INSECT SCIENCE 2023; 30:1773-1783. [PMID: 37162266 DOI: 10.1111/1744-7917.13204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/21/2023] [Accepted: 03/28/2023] [Indexed: 05/11/2023]
Abstract
Male animals may adjust their resource allocations for reproduction and other fitness functions in response to cues from rivals. For instance, adult males increase their investment in sperm for a higher paternity share when they perceive sperm competition risk in their surroundings. In nature, both juveniles and adults may coexist spatially and temporally. Yet, it is not clear how juvenile males of different ages respond to cues from adult rivals and fine-tune their lifetime investment in sperm production and ejaculation in any insect. Here we used the Mediterranean flour moth, Ephestia kuehniella, which produces both fertile eupyrene and infertile apyrene sperm, to explore this question. We demonstrate that the late, but not early, instar larvae are sensitive to adult male cues. As a response, they produce more sperm before emergence and their resultant adults have shorter mating latency and ejaculate more sperm in the first few matings. When the juvenile stage produces more eupyrenes, the adult stops making these sperm, but regardless of the number of apyrenes produced during the juvenile stage, the adult continues to make them. These findings suggest that the number of spermatogonia for eupyrenes may be limited and that for apyrenes may be flexible. Our results show that the insect does not trade off survival, mating frequency, body size, or testis size for sperm production in response to adult males during the larval stage. Knowledge created in the present study offers insight into the stage-dependent sensitivity of juvenile males to cues from adult rivals and subsequent lifetime resource allocations.
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Affiliation(s)
- Junyan Liu
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Xiong Zhao He
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Qiao Wang
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
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3
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Firman RC, André GI, Hadlow JH, Simmons LW. Intergenerational response to sperm competition risk in an invasive mammal. Proc Biol Sci 2023; 290:20222452. [PMID: 37122257 PMCID: PMC10130712 DOI: 10.1098/rspb.2022.2452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Studies of socially mediated phenotypic plasticity have demonstrated adaptive male responses to the 'competitive' environment. Despite this, whether variation in the paternal social environment also influences offspring reproductive potential in an intergenerational context has not yet been examined. Here, we studied the descendants of wild-caught house mice, a destructive pest species worldwide, to address this knowledge gap. We analysed traits that define a 'competitive' phenotype in the sons of males (sires) that had been exposed to either a high-male density (competitive) or high-female density (non-competitive) environment. We report disparate reproductive strategies among the sires: high-male density led to a phenotype geared for competition, while high-female density led to a phenotype that would facilitate elevated mating frequency. Moreover, we found that the competitive responses of sires persisted in the subsequent generation, with the sons of males reared under competition having elevated sperm quality. As all sons were reared under common-garden conditions, variation in their reproductive phenotypes could only have arisen via nongenetic inheritance. We discuss our results in relation to the adaptive advantage of preparing sons for sperm competition and suggest that intergenerational plasticity is a previously unconsidered aspect in invasive mammal fertility control.
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Affiliation(s)
- Renée C Firman
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Gonçalo Igreja André
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Jessica H Hadlow
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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4
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Weber WD, Fisher HS. Sexual selection drives the coevolution of male and female reproductive traits in Peromyscus mice. J Evol Biol 2023; 36:67-81. [PMID: 36480400 PMCID: PMC10107626 DOI: 10.1111/jeb.14126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 09/30/2022] [Accepted: 10/07/2022] [Indexed: 12/13/2022]
Abstract
When females mate with multiple partners within a single reproductive cycle, sperm from rival males may compete for fertilization of a limited number of ova, and females may bias the fertilization of their ova by particular sperm. Over evolutionary timescales, these two forms of selection shape both male and female reproductive physiology when females mate multiply, yet in monogamous systems, post-copulatory sexual selection is weak or absent. Here, we examine how divergent mating strategies within a genus of closely related mice, Peromyscus, have shaped the evolution of reproductive traits. We show that in promiscuous species, males exhibit traits associated with increased sperm production and sperm swimming performance, and females exhibit traits that are predicted to limit sperm access to their ova including increased oviduct length and a larger cumulus cell mass surrounding the ova, compared to monogamous species. Importantly, we found that across species, oviduct length and cumulus cell density are significantly correlated with sperm velocity, but not sperm count or relative testes size, suggesting that these female traits may have coevolved with increased sperm quality rather than quantity. Taken together, our results highlight how male and female traits evolve in concert and respond to changes in the level of post-copulatory sexual selection.
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Affiliation(s)
| | - Heidi S Fisher
- Department of Biology, University of Maryland, College Park, Maryland, USA
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5
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Lymbery RA, Alvaro BJ, Evans JP. Does diet influence ejaculate expenditure under experimentally altered risk of sperm competition in guppies? Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.09.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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6
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Hunnicutt KE, Good JM, Larson EL. Unraveling patterns of disrupted gene expression across a complex tissue. Evolution 2022; 76:275-291. [PMID: 34882778 PMCID: PMC9355168 DOI: 10.1111/evo.14420] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 11/11/2021] [Accepted: 11/26/2021] [Indexed: 02/03/2023]
Abstract
Whole tissue RNASeq is the standard approach for studying gene expression divergence in evolutionary biology and provides a snapshot of the comprehensive transcriptome for a given tissue. However, whole tissues consist of diverse cell types differing in expression profiles, and the cellular composition of these tissues can evolve across species. Here, we investigate the effects of different cellular composition on whole tissue expression profiles. We compared gene expression from whole testes and enriched spermatogenesis populations in two species of house mice, Mus musculus musculus and M. m. domesticus, and their sterile and fertile F1 hybrids, which differ in both cellular composition and regulatory dynamics. We found that cellular composition differences skewed expression profiles and differential gene expression in whole testes samples. Importantly, both approaches were able to detect large-scale patterns such as disrupted X chromosome expression, although whole testes sampling resulted in decreased power to detect differentially expressed genes. We encourage researchers to account for histology in RNASeq and consider methods that reduce sample complexity whenever feasible. Ultimately, we show that differences in cellular composition between tissues can modify expression profiles, potentially altering inferred gene ontological processes, insights into gene network evolution, and processes governing gene expression evolution.
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Affiliation(s)
| | - Jeffrey M. Good
- University of Montana, Division of Biological Sciences, Missoula, MO, 59812
| | - Erica L. Larson
- University of Denver, Department of Biological Sciences, Denver, CO, 80208
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7
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Male sperm storage impairs sperm quality in the zebrafish. Sci Rep 2021; 11:16689. [PMID: 34404815 PMCID: PMC8371167 DOI: 10.1038/s41598-021-94976-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 07/19/2021] [Indexed: 01/03/2023] Open
Abstract
Variation in sperm traits is widely documented both at inter- and intraspecific level. However, sperm traits vary also between ejaculates of the same male, due for example, to fluctuations in female availability. Variability in the opportunities to mate can indeed have important consequences for sperm traits, as it determines how often sperm are used, and thus the rate at which they are produced and how long they are stored before the mating. While being stored within males’ bodies, sperm are subjected to ageing due to oxidative stress. Sperm storage may significantly impair sperm quality, but evidence linking male sperm storage and variation in sperm traits is still scarce. Here, we tested the effect of the duration of sperm storage on within-male variation in sperm traits in the zebrafish, Danio rerio. We found that without mating opportunities, sperm number increased as storage duration increased, indicating that sperm continue to be produced and accumulate over time within males without being discharged in another way. Long sperm storage (12 days) was associated with an overall impairment in sperm quality, namely sperm motility, sperm longevity, and sperm DNA fragmentation, indicating that sperm aged, and their quality declined during storage. Our results confirm that male sperm storage may generate substantial variation in sperm phenotype, a source of variation which is usually neglected but that should be accounted for in experimental protocols aiming to assay sperm traits or maximise fertilization success.
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8
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Liu J, He XZ, Zheng XL, Zhang Y, Wang Q. Pupal Cues Increase Sperm Production but Not Testis Size in an Insect. INSECTS 2021; 12:679. [PMID: 34442245 PMCID: PMC8396453 DOI: 10.3390/insects12080679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/20/2021] [Accepted: 07/26/2021] [Indexed: 12/13/2022]
Abstract
Theoretic and empirical studies show that social surroundings experienced by male insects during their larval or adult stage can influence their testicular investment in diverse ways. Although insect pupae do not feed and crawl, they can communicate using sex-specific and/or non-sex specific cues. Yet, it is unknown, in any insect, whether and how male pupae can fine-tune their resource allocation to sperm production and testis size in response to socio-sexual environments. We investigated this question using a moth, Ephestia kuehniella, which produces fertile eupyrene sperm and unfertile apyrene sperm. We held male pupae individually or in groups with different sex ratios, and dissected adults upon eclosion, measured their testis size, and counted both types of sperm. We demonstrated that after exposure to conspecific pupal cues regardless of sex, male pupae increased production of eupyrenes and apyrenes at the same rate but kept testis size unchanged. We suggest that testis size is fixed after pupation because most morphological traits are formed during the larval stage, allowing little room for pupae to adjust testis size. Like adults, male pupae with fully grown testes have sufficient resources to produce more sperm of both types according to the perceived increase in sperm competition risk.
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Affiliation(s)
- Junyan Liu
- School of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand; (J.L.); (X.Z.H.)
| | - Xiong Z. He
- School of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand; (J.L.); (X.Z.H.)
| | - Xia-Lin Zheng
- Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, National Demonstration Centre for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning 530004, China; (X.-L.Z.); (Y.Z.)
| | - Yujing Zhang
- Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, National Demonstration Centre for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning 530004, China; (X.-L.Z.); (Y.Z.)
| | - Qiao Wang
- School of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand; (J.L.); (X.Z.H.)
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9
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Strategic adjustment of ejaculate quality in response to variation of the socio-sexual environment. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03032-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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10
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Meyer V, Klose M, Lerchl A. Spermatogenesis in the Roborovski hamster (Phodopus roborovskii) and the Chinese hamster (Cricetulus griseus). Andrology 2021; 9:1617-1630. [PMID: 33987974 DOI: 10.1111/andr.13035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Spermatogenesis is an elaborately organized and tightly regulated differentiation process. The spermatogenesis duration is stable within a certain species but highly variable between species of the same family. OBJECTIVES In this study, the spermatogenesis duration of the Roborovski hamster was measured for the first time, and the spermatogenesis duration of the Chinese hamster was re-assessed. MATERIALS AND METHODS Stage classification and cycle length measurement were carried out by labeling the dividing cells with bromodeoxyuridine and an antibody-based chromogen as well as with the periodic acid-Schiff/hematoxylin stain. Analysis was conducted using reference calculation and linear regression. Morphological measurements completed our set of methods. RESULTS The mean duration of one seminiferous epithelium cycle was 8.58 ± 0.34 days (mean ± SEM; Phodopus roborovskii) and 16.59 ± 0.47 days (Cricetulus griseus) based on the reference calculation. Slightly higher results were obtained using linear regression analysis: 9.72 ± 0.41 days for P. roborovskii and 17.64 ± 0.61 days for C. griseus. Additionally, a newly developed exemplary flowchart was proposed for the Roborovski hamster to facilitate spermatogenesis stage classification also in other species. The Chinese hamster presented an unexpectedly high paired epididymides weight of 1.701 ± 0.046 g (mean ± SEM) although having a body weight of only 40.5 ± 0.7 g. However, no significant correlation between the relative epididymis weight and spermatogenesis duration in mammals (Spearman rank correlation: r = -0.119, p = 0.607, n = 21) or rodents could be found (r = 0.045, p = 0.903, n = 11). CONCLUSION Our data emphasize the stability of the spermatogenesis duration within species and its remarkable variability between species. Further research is needed to identify the principal mechanisms and selection drivers that are responsible for such stability within species and the variability between species.
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Affiliation(s)
- Vivian Meyer
- Department of Life Sciences and Chemistry, Jacobs University, Bremen, Germany
| | - Melanie Klose
- Department of Life Sciences and Chemistry, Jacobs University, Bremen, Germany
| | - Alexander Lerchl
- Department of Life Sciences and Chemistry, Jacobs University, Bremen, Germany
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11
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Hobson L, Hurst JL, Stockley P. Increased sperm production linked to competition in the maternal social environment. ROYAL SOCIETY OPEN SCIENCE 2020; 7:201171. [PMID: 33489271 PMCID: PMC7813238 DOI: 10.1098/rsos.201171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
Maternal or early life effects may prepare offspring for similar social conditions to those experienced by their mothers. For males, the ability to achieve mating and fertilization success is a key social challenge. Competitive conditions may therefore favour increased body size or ejaculate production in male offspring. We tested this experimentally by comparing reproductive traits of adult male bank voles (Myodes glareolus), whose mothers had experienced contrasting encounter regimes with female conspecifics while breeding. We found that daily sperm production rates and epididymis mass were significantly higher when dams had experienced more frequent encounters with female conspecifics. This response to maternal and early life experience was specific to sperm production and storage, with no evidence for effects on male body mass or the size of testes and accessory reproductive glands. Our findings reveal a potentially adaptive effect of maternal and early life experience on the development of sperm production, which is worthy of wider investigation.
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12
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Churchill ER, Bridle JR, Thom MD. Spatially clustered resources increase male aggregation and mating duration in Drosophila melanogaster. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Cardozo G, Devigili A, Antonelli P, Pilastro A. Female sperm storage mediates post-copulatory costs and benefits of ejaculate anticipatory plasticity in the guppy. J Evol Biol 2020; 33:1294-1305. [PMID: 32614995 DOI: 10.1111/jeb.13673] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/02/2020] [Accepted: 06/22/2020] [Indexed: 12/12/2022]
Abstract
Males of many species evolved the capability of adjusting their ejaculate phenotype in response to social cues to match the expected mating conditions. When females store sperm for a prolonged time, the expected fitness return of plastic adjustments of ejaculate phenotype may depend on the interval between mating and fertilization. Although prolonged female sperm storage (FSS) increases the opportunity for sperm competition, as a consequence of the longer temporal overlap of ejaculates from several males, it may also create variable selective forces on ejaculate phenotype, for example by exposing trade-offs between sperm velocity and sperm survival. We evaluated the relationship between the plasticity of ejaculate quality and FSS in the guppy, Poecilia reticulata, a polyandrous live-bearing fish in which females store sperm for several months and where stored sperm contribute significantly to a male's lifelong reproductive success. In this species, males respond to the perception of future mating opportunities by increasing the quantity (number) and quality (swimming velocity) of ready-to-use sperm (an anticipatory response called 'sperm priming'). Here we investigated (a) the effect of sperm priming on in vitro sperm viability at stripping and its temporal decline (as an estimate of sperm survival), and (b) the in vivo competitive fertilization success in relation to female sperm storage using artificial insemination. As expected, sperm-primed males produced more numerous and faster sperm, but with a reduced in vitro sperm viability at stripping and after 4 hr, compared with their counterparts. Artificial insemination revealed that the small (nonsignificant) advantage of primed sperm when fertilization immediately follows insemination is reversed when eggs are fertilized by female-stored sperm, weeks after insemination. By suggesting a plastic trade-off between sperm velocity and viability, these results demonstrate that prolonged female sperm storage generates divergent selection pressures on ejaculate phenotype.
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Affiliation(s)
- Gabriela Cardozo
- Laboratorio de Biología del Comportamiento, Instituto de Diversidad y Ecología Animal (IDEA), CONICET-UNC and Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina.,Department of Biology, University of Padova, Padua, Italy
| | - Alessandro Devigili
- Department of Biology, University of Padova, Padua, Italy.,Department of Zoology, Stockholm University, Stockholm, Sweden
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14
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Spagopoulou F, Vega-Trejo R, Head ML, Jennions MD. Shifts in Reproductive Investment in Response to Competitors Lower Male Reproductive Success. Am Nat 2020; 196:355-368. [PMID: 32813996 DOI: 10.1086/709821] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractIn many species, males exhibit phenotypic plasticity in sexually selected traits when exposed to social cues about the intensity of sexual competition. To date, however, few studies have tested how this plasticity affects male reproductive success. We initially tested whether male mosquitofish, Gambusia holbrooki (Poeciliidae), change their investment in traits under pre- and postcopulatory sexual selection depending on the social environment. For a full spermatogenesis cycle, focal males were exposed to visual and chemical cues of rivals that were either present (competitive treatment) or absent (control). Males from the competitive treatment had significantly slower-swimming sperm but did not differ in sperm count from control males. When two males competed for a female, competitive treatment males also made significantly fewer copulation attempts and courtship displays than control males. Further, paternity analysis of 708 offspring from 148 potential sires, testing whether these changes in reproductive traits affected male reproductive success, showed that males previously exposed to cues about the presence of rivals sired significantly fewer offspring when competing with a control male. We discuss several possible explanations for these unusual findings.
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15
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Firman RC, Tedeschi JN, Garcia-Gonzalez F. Sperm sex ratio adjustment in a mammal: perceived male competition leads to elevated proportions of female-producing sperm. Biol Lett 2020; 16:20190929. [PMID: 32486939 DOI: 10.1098/rsbl.2019.0929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mammal sex allocation research has focused almost exclusively on maternal traits, but it is now apparent that fathers can also influence offspring sex ratios. Parents that produce female offspring under conditions of intense male-male competition can benefit with greater assurance of maximized grand-parentage. Adaptive adjustment in the sperm sex ratio, for example with an increase in the production of X-chromosome bearing sperm (CBS), is one potential paternal mechanism for achieving female-biased sex ratios. Here, we tested this mechanistic hypothesis by varying the risk of male-male competition that male house mice perceived during development, and quantifying sperm sex ratios at sexual maturity. Our analyses revealed that males exposed to a competitive 'risk' produced lower proportions of Y-CBS compared to males that matured under 'no risk' of competition. We also explored whether testosterone production was linked to sperm sex ratio variation, but found no evidence to support this. We discuss our findings in relation to the adaptive value of sperm sex ratio adjustments and the role of steroid hormones in socially induced sex allocation.
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Affiliation(s)
- Renée C Firman
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Jamie N Tedeschi
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Francisco Garcia-Gonzalez
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.,Estacion Biológica de Doñana, CSIC, Sevilla, Spain
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16
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Teves ME, Roldan ERS, Krapf D, Strauss III JF, Bhagat V, Sapao P. Sperm Differentiation: The Role of Trafficking of Proteins. Int J Mol Sci 2020; 21:E3702. [PMID: 32456358 PMCID: PMC7279445 DOI: 10.3390/ijms21103702] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/10/2020] [Accepted: 05/20/2020] [Indexed: 12/15/2022] Open
Abstract
Sperm differentiation encompasses a complex sequence of morphological changes that takes place in the seminiferous epithelium. In this process, haploid round spermatids undergo substantial structural and functional alterations, resulting in highly polarized sperm. Hallmark changes during the differentiation process include the formation of new organelles, chromatin condensation and nuclear shaping, elimination of residual cytoplasm, and assembly of the sperm flagella. To achieve these transformations, spermatids have unique mechanisms for protein trafficking that operate in a coordinated fashion. Microtubules and filaments of actin are the main tracks used to facilitate the transport mechanisms, assisted by motor and non-motor proteins, for delivery of vesicular and non-vesicular cargos to specific sites. This review integrates recent findings regarding the role of protein trafficking in sperm differentiation. Although a complete characterization of the interactome of proteins involved in these temporal and spatial processes is not yet known, we propose a model based on the current literature as a framework for future investigations.
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Affiliation(s)
- Maria E. Teves
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond VA 23298, USA;
| | - Eduardo R. S. Roldan
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (CSIC), 28006-Madrid, Spain
| | - Diego Krapf
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO 80523, USA;
| | - Jerome F. Strauss III
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond VA 23298, USA;
| | - Virali Bhagat
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond VA 23298, USA;
| | - Paulene Sapao
- Department of Chemistry, Virginia Commonwealth University, Richmond VA, 23298, USA;
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17
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Firman RC. Exposure to high male density causes maternal stress and female-biased sex ratios in a mammal. Proc Biol Sci 2020; 287:20192909. [PMID: 32370673 PMCID: PMC7282911 DOI: 10.1098/rspb.2019.2909] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/14/2020] [Indexed: 12/29/2022] Open
Abstract
A shift from the traditional perspective that maternal stress is invariably costly has instigated recent interest into its adaptive role in offspring sex allocation. Stress generated by social instability has been linked to offspring sex ratio biases that favour the production of female offspring, which converges with the theoretical prediction that mothers in the poor condition are better off investing in daughters rather than sons. However, previous research has failed to disentangle two different processes: the passive consequence of maternal stress on sex-specific mortality and the adaptive effect of maternal stress at the time of conception. Here, I show that exposure to high male density social conditions leads to elevated stress hormone levels and female-biased in utero offspring sex ratios in house mice (Mus musculus domesticus), and identify that sex-specific offspring production-not sex-specific mortality-is the mechanism accounting for these sex ratio skews. This outcome reflects the optimal fitness scenario for mothers in a male-dominated environment: the production of daughters, who are guaranteed high mate availability, minimizes male-male competition for their sons. Overall, this study supports the idea that maternal stress has the potential to be adaptive and advances our understanding of how exposure to different social conditions can influence sex allocation in mammals.
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Affiliation(s)
- Renée C. Firman
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
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Lavoie MD, Tedeschi JN, Garcia‐Gonzalez F, Firman RC. Exposure to male-dominated environments during development influences sperm sex ratios at sexual maturity. Evol Lett 2019; 3:392-402. [PMID: 31388448 PMCID: PMC6675145 DOI: 10.1002/evl3.123] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/15/2019] [Accepted: 05/21/2019] [Indexed: 11/18/2022] Open
Abstract
Different stages during development are important when it comes to phenotypic adjustments in response to external stimuli. Critical stages in mammals are the prenatal phase, where embryos are exposed to a milieu of sex steroid hormones, and the early-postnatal phase, where littermates interact and experience their incipient social environment. Further, the postmaternal environment will influence the development of traits that are linked to reproductive success in adulthood. Accumulated evidence of male-driven sex allocation establishes the currently untested hypothesis that the sperm sex ratio is a plastic trait that can be mediated to align with prevailing social conditions. Here, we used natural variation in the maternal environment and experimentally manipulated the postmaternal environment to identify the importance of these developmental phases on sperm sex ratio adjustments in wild house mice (Mus musculus domesticus). We found that male density in both environments was predictive of sperm sex ratios at sexual maturity: males from more male-biased litters and males maturing under high male density produced elevated levels of Y-chromosome-bearing sperm. Our findings indicate that the sperm sex ratio is a variable phenotypic trait that responds to the external environment, and highlight the potential that these adjustments function as a mechanism of male-driven sex allocation.
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Affiliation(s)
- Misha D. Lavoie
- School of Biological Sciences (M092), Centre for Evolutionary BiologyThe University of Western AustraliaCrawleyWA6009Australia
| | - Jamie N. Tedeschi
- School of Biological Sciences (M092), Centre for Evolutionary BiologyThe University of Western AustraliaCrawleyWA6009Australia
| | - Francisco Garcia‐Gonzalez
- School of Biological Sciences (M092), Centre for Evolutionary BiologyThe University of Western AustraliaCrawleyWA6009Australia
- Estacion Biológica de DoñanaCSICSevillaSpain
| | - Renée C. Firman
- School of Biological Sciences (M092), Centre for Evolutionary BiologyThe University of Western AustraliaCrawleyWA6009Australia
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Andrade MC. Sexual selection and social context: Web-building spiders as emerging models for adaptive plasticity. ADVANCES IN THE STUDY OF BEHAVIOR 2019. [DOI: 10.1016/bs.asb.2019.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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