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Friesen CR, Noble DWA, Olsson M. The role of oxidative stress in postcopulatory selection. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200065. [PMID: 33070735 DOI: 10.1098/rstb.2020.0065] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Two decades ago, von Schantz et al. (von Schantz T, Bensch S, Grahn M, Hasselquist D, Wittzell H. 1999 Good genes, oxidative stress and condition-dependent sexual signals. Proc. R. Soc. B 266, 1-12. (doi:10.1098/rspb.1999.0597)) united oxidative stress (OS) biology with sexual selection and life-history theory. This set the scene for analysis of how evolutionary trade-offs may be mediated by the increase in reactive molecules resulting from metabolic processes at reproduction. Despite 30 years of research on OS effects on infertility in humans, one research area that has been left behind in this integration of evolution and OS biology is postcopulatory sexual selection-this integration is long overdue. We review the basic mechanisms in OS biology, why mitochondria are the primary source of ROS and ATP production during oxidative metabolism, and why sperm, and its performance, is uniquely susceptible to OS. We also review how postcopulatory processes select for antioxidation in seminal fluids to counter OS and the implications of the net outcome of these processes on sperm damage, sperm storage, and female and oocyte manipulation of sperm metabolism and repair of DNA to enhance offspring fitness. This article is part of the theme issue 'Fifty years of sperm competition'.
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Affiliation(s)
- Christopher R Friesen
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, New South Wales, Australia
| | - Daniel W A Noble
- Division of Ecology and Evolution, Australian National University, Canberra, Australian Capital Territory, ACT 2600, Australia
| | - Mats Olsson
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, New South Wales, Australia.,Department of Biological and Environmental Sciences, University of Gothenburg, Box 463, SE 405 30, Gothenburg, Sweden
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Fasel NJ, Kołodziej-Sobocińska M, Komar E, Zegarek M, Ruczyński I. Penis size and sperm quality, are all bats grey in the dark? Curr Zool 2019; 65:697-703. [PMID: 31857816 PMCID: PMC6911842 DOI: 10.1093/cz/zoy094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 12/04/2018] [Indexed: 11/12/2022] Open
Abstract
Penises play a key role in sperm transport and in stimulating female genitals. This should impact post-copulatory competition, and expose penis characteristics to sexual selective pressures. Studies of male genitalia have repeatedly reported negative static allometries, which mean that, within species, large males have disproportionally small genitals when compared with smaller individuals. Males of some sperm-storing bat species may stand as an exception to such a pattern by arousing from hibernation to copulate with torpid females. The selection for large penises might take place, if a long organ provides advantages during post-copulatory competition and/or if females have evolved mechanisms allowing the choice of sire, relying on characters other than pre-copulatory traits (e.g., penis size). In this study, we measured dimensions of the erected penis in 4 sperm-storing bat species. Furthermore, we collected sperm and evaluated the link between penis dimensions and sperm velocity. Our results revealed steep allometric slopes of the erected penis length in Barbastella barbastellus and an inverse allometry of penis head width in Myotis nattereri. More detailed studies of copulatory behavior are urgently needed to explain the range of observed scaling relations. Furthermore, penis head width correlates with sperm velocity in Plecotus auritus. For this last species, we propose that penis shape might act as a marker of male fertility.
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Affiliation(s)
- Nicolas Jean Fasel
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse, Berlin, Germany
| | | | - Ewa Komar
- Mammal Research Institute Polish Academy of Sciences, Białowieża, Poland
| | - Marcin Zegarek
- Mammal Research Institute Polish Academy of Sciences, Białowieża, Poland
| | - Ireneusz Ruczyński
- Mammal Research Institute Polish Academy of Sciences, Białowieża, Poland
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Meniri M, Gohon F, Gning O, Glauser G, Vallat A, Fasel NJ, Helfenstein F. Experimental manipulation of reproductive tactics in Seba's short-tailed bats: consequences on sperm quality and oxidative status. Curr Zool 2019; 65:609-616. [PMID: 31857807 PMCID: PMC6911846 DOI: 10.1093/cz/zoz011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/14/2019] [Indexed: 12/25/2022] Open
Abstract
To reproduce, males have to fertilize the female's eggs, sometimes in competition with ejaculates of other males. In species where males display alternative reproductive tactics, whereby territorial males secure mating and non-territorial males have to sneak copulations, the latter might be expected to invest relatively more resources towards sperm quality compared with the territorial males. Sperm cells are especially vulnerable to oxidative stress, which reduces male fertility. Therefore, antioxidant resources are expected to modulate sperm quality, and might be allocated differently between reproductive tactics. To test the link between reproductive tactics, redox profile and sperm quality, we experimentally induced changes in the reproductive tactics of 39 captive males Seba's short-tailed bats Carollia perspicillata. We monitored the blood and ejaculate oxidative balance, and the sperm quality before, 7 days and 21 days after the manipulation of reproductive tactic. Although ejaculates' oxidative damage was negatively related to sperm velocity, males exhibited similar blood and ejaculates redox profiles and similar sperm quality, regardless of their reproductive tactic. Possibly, these results arise as a consequence of some constraints having been lifted during the experiment. Our results also suggest that, in Seba's short-tailed bats, the expression of alternative reproductive tactics is not subjected to strong oxidative constraints. Furthermore, our results could reflect an absence of trade-off between pre- and post-copulatory traits in harem males, as they could be selected to invest both in female attraction and sperm quality, as a consequence of their inability to fully monopolize females.
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Affiliation(s)
- Magali Meniri
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland
| | - Florence Gohon
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland
| | - Ophélie Gning
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland
| | - Gaétan Glauser
- Neuchatel Platform of Analytical Chemistry, University of Neuchâtel, Switzerland
| | - Armelle Vallat
- Neuchatel Platform of Analytical Chemistry, University of Neuchâtel, Switzerland
| | | | - Fabrice Helfenstein
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland
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Humann-Guilleminot S, Tassin de Montaigu C, Sire J, Grünig S, Gning O, Glauser G, Vallat A, Helfenstein F. A sublethal dose of the neonicotinoid insecticide acetamiprid reduces sperm density in a songbird. ENVIRONMENTAL RESEARCH 2019; 177:108589. [PMID: 31330492 DOI: 10.1016/j.envres.2019.108589] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/20/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Farmland bird species are particularly exposed to pesticides through various pathways. Among pesticides, neonicotinoids insecticides are commonly used in agriculture, but their influence on bird reproductive capacities is poorly understood. In this study, we experimentally tested the effects of the neonicotinoid acetamiprid on House sparrows' sperm quality and oxidative status following ingestion of a low and field-realistic dose of the compound. To do so, 56 males were captured, held and orally dosed seven times over 19 days of experiment with either a saline solution (control) or an acetamiprid-saline solution, and sperm samples were retrieved before and after the experiment. The overall dose given to the birds corresponded to 0.5% of the LD50 for the Zebra finch (5.7 mg/kg BW) spread into 7 separate doses and administered every three days over the entire duration of the study (ca. 0.07% LD50 per oral dose). Sperm mobility and sperm oxidative status were unaffected by the treatment, but sperm density was. Birds that received oral doses of acetamiprid suffered a significant decline in their sperm density compared to control birds. This result was confirmed by a significant decrease in the activity of the antioxidant enzyme SOD in the sperm of acetamiprid-dosed birds. These results provide the first evidence of sublethal toxicity of acetamiprid in a songbird and suggest that passerine birds' fertility may be negatively affected by very small doses of neonicotinoids in the wild.
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Affiliation(s)
- S Humann-Guilleminot
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland; Swiss Ornithological Institute, Sempach, Switzerland.
| | - C Tassin de Montaigu
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - J Sire
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - S Grünig
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - O Gning
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - G Glauser
- Neuchâtel Platform of Analytical Chemistry, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - A Vallat
- Neuchâtel Platform of Analytical Chemistry, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - F Helfenstein
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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Rojas Mora A, Meniri M, Ciprietti S, Helfenstein F. Is sperm morphology functionally related to sperm swimming ability? A case study in a wild passerine bird with male hierarchies. BMC Evol Biol 2018; 18:142. [PMID: 30231935 PMCID: PMC6146611 DOI: 10.1186/s12862-018-1260-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 09/11/2018] [Indexed: 11/21/2022] Open
Abstract
Background Sexual selection continues after copulation via either sperm competition or cryptic female choice, and favors sperm traits that maximize sperm competitiveness. Both sperm swimming velocity and longevity are important determinants of the outcome of sperm competition. Theoretically, sperm morphology can influence sperm velocity at least in three different non-exclusive ways: (i) longer sperm may generate more propelling thrust, (ii) bigger midpieces may produce more energy, and/or (iii) larger flagella or mid-pieces relative to the head size may compensate for the drag forces around the head. A growing number of studies have investigated the relationship of sperm morphology with sperm performance, which remains equivocal at both the inter- and intra-specific levels. Here, we used House Sparrows to test the functional relationship between sperm morphology with sperm velocity and longevity. Based on a previous study showing that sperm swimming ability covaries with social rank, we predicted that —if a functional relationship exists—1) sperm morphology should differ across social ranks, and 2) correlations between sperm morphology and sperm velocity and/or sperm longevity should be constant across social ranks. Results We found no differences in sperm morphology across social ranks. Moreover, we found that sperm morphology may be correlated with sperm velocity, but such relationship varied across social ranks. This result contradicts the hypothesis of a functional relationship between sperm morphology and sperm performance. Finally, after experimentally manipulating social ranks, we observed that relationships between sperm morphology and sperm velocity and/or sperm longevity disappeared or changed direction. Conclusions We suggest that in species with internal fertilization, while sperm morphology is likely constrained by the morphology of the female sperm storage organs, selection may act upon physiological traits that enhance sperm performance. Hence, these two selection forces could decouple sperm performance from sperm morphology. Electronic supplementary material The online version of this article (10.1186/s12862-018-1260-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alfonso Rojas Mora
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, Faculty of Sciences, University of Neuchatel, Neuchatel, Switzerland. .,Present Address: Laboratory of Ecology and Epidemiology of Parasites, Institute of Biology, Faculty of Sciences, University of Neuchatel, Rue Emile-Argand 11, 2000, Neuchatel, Switzerland.
| | - Magali Meniri
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, Faculty of Sciences, University of Neuchatel, Neuchatel, Switzerland
| | - Sabrina Ciprietti
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, Faculty of Sciences, University of Neuchatel, Neuchatel, Switzerland
| | - Fabrice Helfenstein
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, Faculty of Sciences, University of Neuchatel, Neuchatel, Switzerland
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Rojas Mora A, Meniri M, Gning O, Glauser G, Vallat A, Helfenstein F. Antioxidant allocation modulates sperm quality across changing social environments. PLoS One 2017; 12:e0176385. [PMID: 28472052 PMCID: PMC5417513 DOI: 10.1371/journal.pone.0176385] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 04/10/2017] [Indexed: 11/20/2022] Open
Abstract
In promiscuous species, male reproductive success depends on their ability to mate with fertile females and on the fertilizing ability of their sperm. In such species, theory predicts that, owing to a trade-off between pre- and post-copulatory reproductive traits, males with lesser access to females should increase resource investment into those sperm traits that enhance fertilization success–usually referred to as ejaculate quality. This prediction has been validated in several taxa, yet studies on the physiological mechanisms modulating ejaculate quality are lacking. Sperm cells are highly vulnerable to oxidative stress, which impairs male fertility. Therefore, males that better protect their sperm from oxidative stress are expected to achieve higher ejaculate quality. Based on theoretical expectations, and since social dominance is a major determinant of mating opportunity, we predicted that subordinate males should invest more into the antioxidant protection of their sperm in order to achieve higher ejaculate quality. We maintained 60 male and 60 female wild-caught house sparrows Passer domesticus in outdoor aviaries, where we experimentally manipulated male social status to test our predictions. We measured cellular oxidative stress and enzymatic antioxidant activity in blood and sperm both before and after manipulating social ranks. Before manipulating the social status, we found that ejaculate viability correlated with oxidative stress level in sperm, with dominant males producing more oxidized and less viable ejaculates. Further, males at the lower end of the hierarchy produced ejaculates of similar quality to those of dominant males, suggesting that restricted access to resources might limit male reproductive strategies. After experimentally manipulating the social status, males matched their ejaculate quality to their new rank, while increases in antioxidant investment into ejaculates paralleled increases in ejaculate viability. Oxidative stress has been proposed as a general constraint to the evolution of life histories. Our results highlight oxidative stress and strategic antioxidant allocation as important proximate physiological mechanisms underlying male reproductive strategies.
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Affiliation(s)
- Alfonso Rojas Mora
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Magali Meniri
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ophélie Gning
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Gaëtan Glauser
- Neuchatel Platform of Analytical Chemistry, Institute of Chemistry, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Armelle Vallat
- Neuchatel Platform of Analytical Chemistry, Institute of Chemistry, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Fabrice Helfenstein
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
- * E-mail:
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Rojas Mora A, Meniri M, Ciprietti S, Helfenstein F. Social dominance explains within-ejaculate variation in sperm design in a passerine bird. BMC Evol Biol 2017; 17:66. [PMID: 28259157 PMCID: PMC5336654 DOI: 10.1186/s12862-017-0914-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 02/15/2017] [Indexed: 11/10/2022] Open
Abstract
Background Comparative studies suggest that sperm competition exerts stabilizing selection towards an optimal sperm design – e.g., the relative size and covariation of different sperm sections or a quantitative measure of sperm shape - that maximizes male fertility, which results in reduced levels of within-male variation in sperm morphology. Yet, these studies also reveal substantial amounts of unexplained within-ejaculate variance, and the factors presiding to the maintenance of such within-male variation in sperm design at the population level still remain to be identified. Sperm competition models predict that males should progressively invest more resources in their germline as their mating costs increase, i.e., the soma/germline allocation trade-off hypothesis. When access to fertile females is determined by social dominance, the soma/germline allocation trade-off hypothesis predicts that dominant males should invest less in the control of spermatogenesis. Hence, dominance should positively correlate with within-male variance in sperm design. Results In support of this hypothesis, we found that dominant house sparrow males produce ejaculates with higher levels of within-ejaculate variation in sperm design compared to subordinate males. However, after experimentally manipulating male social status, this pattern was not maintained. Conclusions Our results suggest that males might control variation in sperm design according to their social status to some extent. Yet, it seems that such within-ejaculate variation in sperm design cannot be rapidly adjusted to a new status. While variation in sperm design could result from various non-exclusive sources, we discuss how strategic allocation of resources to the somatic vs. the germline functions could be an important process shaping the relationship between within-male variation in sperm design and social status. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0914-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alfonso Rojas Mora
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchatel, Rue Emile-Argand 11, Neuchatel, Switzerland
| | - Magali Meniri
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchatel, Rue Emile-Argand 11, Neuchatel, Switzerland
| | - Sabrina Ciprietti
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchatel, Rue Emile-Argand 11, Neuchatel, Switzerland
| | - Fabrice Helfenstein
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchatel, Rue Emile-Argand 11, Neuchatel, Switzerland.
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Alternative reproductive tactics, sperm mobility and oxidative stress in Carollia perspicillata (Seba’s short-tailed bat). Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2251-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Knight K. Sneaker male athletic sperm outstrips harem male sperm to get egg. J Exp Biol 2016. [DOI: 10.1242/jeb.141887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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