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Valencia-Aguilar A, Ringler E, Lüpold S, Guayasamin JM, Prado CPA. Evolutionary trade-offs between testes size and parenting in Neotropical glassfrogs. Proc Biol Sci 2024; 291:20240054. [PMID: 38351799 PMCID: PMC10865008 DOI: 10.1098/rspb.2024.0054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 01/18/2024] [Indexed: 02/16/2024] Open
Abstract
In males, large testes size signifies high sperm production and is commonly linked to heightened sperm competition levels. It may also evolve as a response to an elevated risk of sperm depletion due to multiple mating or large clutch sizes. Conversely, weapons, mate or clutch guarding may allow individuals to monopolize mating events and preclude sperm competition, thereby reducing the selection of large testes. Herein, we examined how paternal care, sexual size dimorphism (SSD), weaponry and female fecundity are linked to testes size in glassfrogs. We found that paternal care was associated with a reduction in relative testes size, suggesting an evolutionary trade-off between testes size and parenting. Although females were slightly larger than males and species with paternal care tended to have larger clutches, there was no significant relationship between SSD, clutch size and relative testes size. These findings suggest that the evolution of testes size in glassfrogs is influenced by sperm competition risk, rather than sperm depletion risk. We infer that clutch guarding precludes the risk of fertilization by other males and consequently diminishes selective pressure for larger testes. Our study highlights the prominent role of paternal care in the evolution of testes size in species with external fertilization.
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Affiliation(s)
- Anyelet Valencia-Aguilar
- Pós-Graduação em Ecologia, Evolução e Biodiversidade, Instituto de Biociências, São Paulo State University (Unesp), Rio Claro, São Paulo 13506-900, Brazil
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, 3032 Bern, Switzerland
| | - Eva Ringler
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, 3032 Bern, Switzerland
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zurich, Switzerland
| | - Juan M. Guayasamin
- Instituto Biósfera USFQ, Laboratorio de Biología Evolutiva, Universidad San Francisco de Quito USFQ Cumbayá, Quito, Ecuador
| | - Cynthia P. A. Prado
- Pós-Graduação em Ecologia, Evolução e Biodiversidade, Instituto de Biociências, São Paulo State University (Unesp), Rio Claro, São Paulo 13506-900, Brazil
- Departamento de Morfologia e Fisiologia Animal, FCAV, São Paulo State University (Unesp), Jaboticabal, São Paulo 14884-900, Brazil
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2
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Laugen AT, Hosken DJ, Reinhold K, Schwarzenbach GA, Hoeck PEA, Bussière LF, Blanckenhorn WU, Lüpold S. Sperm competition in yellow dung flies: No consistent effect of sperm size. J Evol Biol 2022; 35:1309-1318. [PMID: 35972882 DOI: 10.1111/jeb.14073] [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: 05/03/2022] [Revised: 07/09/2022] [Accepted: 07/12/2022] [Indexed: 01/07/2023]
Abstract
The male competition for fertilization that results from female multiple mating promotes the evolution of increased sperm numbers and can impact sperm morphology, with theory predicting that longer sperm can at times be advantageous during sperm competition. If so, males with longer sperm should sire more offspring than competitors with shorter sperm. Few studies have directly tested this prediction, and findings are inconsistent. Here we assessed whether longer sperm provide a competitive advantage in the yellow dung fly (Scathophaga stercoraria; Diptera: Scathophagidae). Initially, we let brothers with different temperature-mediated mean sperm lengths compete - thus minimizing confounding effects of genetic background - and found no clear advantage of longer sperm. We then used flies from lines subjected to bidirectional selection on phenoloxidase activity that had shown correlated evolutionary responses in sperm and female spermathecal duct lengths. This experiment also yielded no main effect of sperm size on siring success. Instead, there was a trend for a shorter-sperm advantage, but only when competing in females with longer spermathecal ducts. Our data corroborated many previously reported findings (last-male precedence, effects of copula duration and body size), suggesting our failure to find sperm size effects is not inherently due to our experimental protocols. We conclude that longer sperm are not competitively superior in yellow dung flies under most circumstances, and that, consistent with previous work, in this species competitive fertilization success is primarily determined by the relative numbers of sperm competing.
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Affiliation(s)
- Ane T Laugen
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Zurich, Switzerland.,Centre for Coastal Research, Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - David J Hosken
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Zurich, Switzerland.,Centre for Ecology and Conservation, University of Exeter in Cornwall, Penryn, UK
| | - Klaus Reinhold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Zurich, Switzerland.,Evolutionsbiologie, Universität Bielefeld, Bielefeld, Germany
| | - Gioia A Schwarzenbach
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Zurich, Switzerland
| | - Paquita E A Hoeck
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Zurich, Switzerland
| | - Luc F Bussière
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Zurich, Switzerland.,Biology and Environmental Sciences, University of Gothenburg and Gothenburg Global Biodiversity Centre, Gothenburg, Sweden
| | - Wolf U Blanckenhorn
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Zurich, Switzerland
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Zurich, Switzerland
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3
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Watt AM, Marcec-Greaves R, Hinkson KM, Poo S, Roberts B, Pitcher TE. Effects of age on sperm quality metrics in endangered Mississippi gopher frogs (Lithobates sevosus) from captive populations used for controlled propagation and reintroduction efforts. Zoo Biol 2021; 40:218-226. [PMID: 33606315 DOI: 10.1002/zoo.21594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/08/2021] [Indexed: 01/13/2023]
Abstract
A decline in sperm quality with age is a common prediction of senescence-based hypotheses and empirical studies. While widely studied across taxa, there is little known on the effect of ageing on sperm quality in amphibians, especially in captive populations used for controlled propagation and reintroduction efforts. Here, we investigated variation in sperm quality metrics (i.e., motility, concentration, and morphology) in the endangered Mississippi gopher frog (Lithobates sevosus) among males of three age categories using individuals from captive breeding populations housed at three different zoological institutions. Different aged males across the species expectant lifespan (1-9, 1-2, 3-4, and 8-9-year-old subcategories) were chosen in an attempt to identify an optimal breeding age relevant for captive breeding programs. Moreover, we explored and statistically controlled for potential differences in sperm quality which may be attributed to the type of induction hormones and source populations that differed among institutions. Results indicated that males of different ages did not differ in sperm motility or concentration. However, we did find that older males (8-9 years old) had significantly longer sperm than other age categories and younger males (1-2 years old) had significantly more atypical sperm than other age categories. Furthermore, we found no significant differences in any sperm quality metrics between the different induction hormones or source populations used at the different institutions. Within a captive breeding program, this information is especially valuable as our results indicate that males that have only recently sexually matured may not be ready to breed, while older males maintain sperm quality metrics presumably related to fertilization success.
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Affiliation(s)
- Ashley M Watt
- Department of Integrative Biology, University of Windsor, Windsor, Ontario, Canada
| | - Ruth Marcec-Greaves
- National Amphibian Conservation Center, Detroit Zoological Society, Royal Oak, Michigan, USA
| | - Kristin M Hinkson
- Department of Conservation and Research, Memphis Zoological Society, Memphis, Tennessee, USA
| | - Sinlan Poo
- Department of Conservation and Research, Memphis Zoological Society, Memphis, Tennessee, USA
| | - Beth Roberts
- Department of Conservation and Research, Memphis Zoological Society, Memphis, Tennessee, USA
| | - Trevor E Pitcher
- Department of Integrative Biology, University of Windsor, Windsor, Ontario, Canada.,Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada
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4
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Rudin-Bitterli TS, Mitchell NJ, Evans JP. Extensive geographical variation in testes size and ejaculate traits in a terrestrial-breeding frog. Biol Lett 2020; 16:20200411. [PMID: 32991823 PMCID: PMC7532705 DOI: 10.1098/rsbl.2020.0411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/08/2020] [Indexed: 11/12/2022] Open
Abstract
Ejaculate traits vary extensively among individuals and species, but little is known about their variation among populations of the same species. Here, we investigated patterns of intraspecific variation in male reproductive investment in the terrestrial-breeding frog Pseudophryne guentheri. Like most anurans, breeding activity in P. guentheri is cued by precipitation, and therefore the timing and duration of breeding seasons differ among geographically separated populations, potentially leading to differences in the level of sperm competition. We, therefore, anticipated local adaptation in sperm traits that reflect these phenological differences among populations. Our analysis of six natural populations across a rainfall gradient revealed significant divergence in testes and ejaculate traits that correspond with annual rainfall and rainfall seasonality; males from the northern and drier edge of the species range had significantly smaller testes containing fewer, smaller and less motile sperm compared with those from mesic central populations. These findings may reflect spatial variation in the strength of postcopulatory sexual selection, likely driven by local patterns of precipitation.
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Affiliation(s)
| | | | - Jonathan P. Evans
- School of Biological Sciences, University of Western Australia, Crawley, WA 6009, Australia
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5
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Watt AM, Marcec-Greaves R, Pitcher TE. Time from injection of luteinizing hormone-releasing hormone analog affects sperm quality in the critically endangered Mississippi gopher frog (Lithobates sevosus). Zoo Biol 2019; 39:23-28. [PMID: 31617256 DOI: 10.1002/zoo.21519] [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: 11/07/2018] [Revised: 09/18/2019] [Accepted: 09/30/2019] [Indexed: 11/07/2022]
Abstract
The objective of this study was to investigate variation in sperm quality metrics (motility, velocity, and concentration) in the critically endangered Mississippi gopher frog (Lithobates sevosus) over three sampling time points after a luteinizing hormone-releasing hormone analog (LHRHa) induction injection. Sperm was repeatedly collected from 11 individuals over three sampling times (30, 60, and 120 min) after injection. Variation in sperm quality was investigated using a repeated-measures mixed model approach. Repeated measures analyses of variance showed a significant effect of sampling time for percent motility and velocity. Concentration was found to be marginally related to sampling time, while progressive motility was not significantly related to time after injection. Our findings are important for optimizing assisted reproduction-related fertilization success and increasing the successful propagation of endangered species of imperiled frogs in captive breeding programs.
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Affiliation(s)
- Ashley Michelle Watt
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada
| | - Ruth Marcec-Greaves
- National Amphibian Conservation Center, Detroit Zoological Society, Royal Oak, Michigan
| | - Trevor Edgar Pitcher
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada.,Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada
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6
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Dzyuba V, Sampels S, Ninhaus-Silveira A, Kahanec M, Veríssimo-Silveira R, Rodina M, Cosson J, Boryshpolets S, Selinger M, Sterba J, Dzyuba B. Sperm motility and lipid composition in internally fertilizing ocellate river stingray Potamotrygon motoro. Theriogenology 2019; 130:26-35. [PMID: 30856412 DOI: 10.1016/j.theriogenology.2019.02.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 02/24/2019] [Indexed: 01/13/2023]
Abstract
All extant groups of Elasmobranches have internal fertilization and the structure of the male reproductive organs is very specific: sperm passes from the internal organs via the cloaca, but the male copulating organ (clasper) is distant from the cloaca. This suggests that sperm can contact the surrounding medium before fertilization. Because of this involvement with the environment, external signaling in sperm motility activation could occur in these species even though their fertilization mode is internal. In this case, spermatozoa of Elasmobranches should hypothetically possess a specific structure and membrane lipid composition which supports physiological functions of the sperm associated with environmental tonicity changes occurring at fertilization. Additionally, sperm motility properties in these taxa are poorly understood. The current study examined sperm lipid composition and motility under different environmental conditions for the ocellate river stingray, Potamotrygon motoro, an endemic South America freshwater species. Sperm samples were collected from six mature males during the natural spawning period. Sperm motility was examined in seminal fluid and fresh water by light video microscopy. Helical flagellar motion was observed in seminal fluid and resulted in spermatozoon progression; however, when diluted in fresh water, spermatozoa were immotile and had compromised structure. Lipid class and fatty acid (FA) composition of spermatozoa was analyzed by thin layer and gas chromatography. Spermatozoa FAs consisted of 33 ± 1% saturated FAs, 28 ± 1% monounsaturated FAs (MUFAs), and 41 ± 1% polyunsaturated FAs (PUFAs), and a high content of n-6 FAs (32 ± 2%) was measured. These results allowed us to conclude that sperm transfer from P. motoro male into female should occur without coming into contact with the hypotonic environment so as to preserve potent motility. In addition, this unusual reproductive strategy is associated with specific spermatozoa structure and lipid composition. Low level of docosahexaenoic acid and relatively low PUFA/MUFA ratio probably account for the relatively low fluidity of freshwater stingray membrane and can be the main reason for its low tolerance to hypotonicity.
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Affiliation(s)
- Viktoriya Dzyuba
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Sabine Sampels
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25, Vodňany, Czech Republic; Swedish University of Agricultural Sciences, Department of Molecular Sciences, PO Box 7015, 75007, Uppsala, Sweden
| | - Alexandre Ninhaus-Silveira
- São Paulo State University, Ilha Solteira, Faculty of Engineering, Department of Biology and Zootechny, Neotropical Ichthyology Laboratory - LINEO, Monção Street, 226, 15385-000, Ilha Solteira, SP, Brazil
| | - Martin Kahanec
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Rosicleire Veríssimo-Silveira
- São Paulo State University, Ilha Solteira, Faculty of Engineering, Department of Biology and Zootechny, Neotropical Ichthyology Laboratory - LINEO, Monção Street, 226, 15385-000, Ilha Solteira, SP, Brazil
| | - Marek Rodina
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Jacky Cosson
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Sergii Boryshpolets
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25, Vodňany, Czech Republic
| | - Martin Selinger
- University of South Bohemia in České Budějovice, Faculty of Science, Institute of Chemistry, Branišovská 1760, 370 05, České Budějovice, Czech Republic; Biology Centre of Czech Academy of Sciences, Institute of Parasitology, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Jan Sterba
- University of South Bohemia in České Budějovice, Faculty of Science, Institute of Chemistry, Branišovská 1760, 370 05, České Budějovice, Czech Republic; Biology Centre of Czech Academy of Sciences, Institute of Parasitology, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Borys Dzyuba
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Zátiší 728/II, 389 25, Vodňany, Czech Republic.
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7
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Turani B, Aliko V, Faggio C. Allurin and egg jelly coat impact on in-vitro fertilization success of endangered Albanian water frog, Pelophylax shqipericus. Nat Prod Res 2018; 34:830-837. [PMID: 30445855 DOI: 10.1080/14786419.2018.1508147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Amphibian egg-jelly coat plays an important role in successful fertilization and development. Here, we ask whether proteins like allurin in the jelly coats of frog eggs might influence fertilization rate success. Using in vitro fertilization of Albanian water frog, Pelophylax shqipericus, we found that body cavity eggs or eggs deprived of jelly coat were not fertilized, compromising the success of in vitro fertilization procedure. When de-jellied eggs were inseminated with sperm suspension, the fertilization efficiency is dramatically decreased even inhibited, suggesting that the gel structure is one of the major factors in the achievement of fertilization in the frogs. Fertilization of de-jellied eggs with sperm pre-treated with egg jelly coat, restored the fertilization competency. Such a result suggests that egg jelly coat probably guides the sperm to the egg surface while maintaining the fertilization ability, contributing to a successful in vitro fertilization of Pelophylax shqipericus.
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Affiliation(s)
- Blerta Turani
- Department of Biology, Faculty of Natural Sciences, University of Tirana, Tirana, Albania
| | - Valbona Aliko
- Department of Biology, Faculty of Natural Sciences, University of Tirana, Tirana, Albania
| | - Caterina Faggio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
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8
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Rudin-Bitterli TS, Mitchell NJ, Evans JP. Environmental Stress Increases the Magnitude of Nonadditive Genetic Variation in Offspring Fitness in the Frog Crinia georgiana. Am Nat 2018; 192:461-478. [DOI: 10.1086/699231] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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9
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Dittrich C, Rodríguez A, Segev O, Drakulić S, Feldhaar H, Vences M, Rödel MO. Temporal migration patterns and mating tactics influence size-assortative mating in Rana temporaria. Behav Ecol 2018; 29:418-428. [PMID: 29622935 PMCID: PMC5873255 DOI: 10.1093/beheco/arx188] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 10/20/2017] [Accepted: 12/14/2017] [Indexed: 11/23/2022] Open
Abstract
Assortative mating is a common pattern in sexually reproducing species, but the mechanisms leading to assortment remain poorly understood. By using the European common frog (Rana temporaria) as a model, we aim to understand the mechanisms leading to size-assortative mating in amphibians. With data from natural populations collected over several years, we first show a consistent pattern of size-assortative mating across our 2 study populations. We subsequently ask if assortative mating may be explained by mate availability due to temporal segregation of migrating individuals with specific sizes. With additional experiments, we finally assess whether size-assortative mating is adaptive, i.e. influenced by mating competition among males, or by reduced fertilization in size-mismatched pairs. We find that size-assortative mating is in accordance with differences in mate availability during migration, where larger individuals of both sexes reach breeding ponds earlier than smaller individuals. We observe an indiscriminate mate choice behavior of small males and an advantage of larger males pairing with females during scramble competition. The tactic of small males, to be faster and less discriminative than large males, may increase their chances to get access to females. Experimental tests indicate that the fertilization success is not affected by size assortment. However, since female fecundity is highly correlated with body size, males preferring larger females should maximize their number of offspring. Therefore, we conclude that in this frog species mate choice is more complex than formerly believed.
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Affiliation(s)
- Carolin Dittrich
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Ariel Rodríguez
- TU Braunschweig, Zoologisches Institut, Evolutionsbiologie, Braunschweig, Germany
- University of Veterinary Medicine Hannover, Institute of Zoology, Hannover, Germany
| | - Ori Segev
- University of Haifa, Faculty of Science, Institute of Evolution, Community Ecology Lab, Haifa, Israel
| | - Sanja Drakulić
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Heike Feldhaar
- University of Bayreuth, Animal Population Ecology, Bayreuth, Germany
| | - Miguel Vences
- TU Braunschweig, Zoologisches Institut, Evolutionsbiologie, Braunschweig, Germany
| | - Mark-Oliver Rödel
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
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10
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Zhang L, An D, He Y, Li Z, Fang B, Chen X, Lu X. Variation in testis weight of the Tibetan toad Scutiger boulengeri along a narrow altitudinal gradient. ANIM BIOL 2018. [DOI: 10.1163/15707563-17000016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Life-history theory predicts that organisms inhabiting harsh environments such as high altitudes should invest less in reproduction and more in survival. Testis size is associated with the intensity of male-male competition for mating and thus may be treated as an indicator of male reproductive investment. Hence, it may be expected that organisms will reduce their testis size with increasingly harsh environments. Here we test this prediction in a toad species, Scutiger boulengeri, endemic to the Tibetan plateau using data from three populations located at altitudes of 4078, 4276, and 4387 m. Consistent with the prediction, male toads exhibited smaller testes at higher altitudes, despite the relatively narrow altitudinal span. It is likely that cold climates and strong seasonality constrain the ability of high-altitude male toads to allocate more energy into reproduction, thereby leading to small testis size. In addition, the left testis was significantly heavier than the right one and the degree of size asymmetry was unrelated to either altitude or body condition.
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Affiliation(s)
- Lixia Zhang
- 1Department of Ecology, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Dong An
- 1Department of Ecology, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Yuxiao He
- 1Department of Ecology, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Zhibing Li
- 1Department of Ecology, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Bohao Fang
- 2Department of Ecology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaohong Chen
- 1Department of Ecology, College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Xin Lu
- 2Department of Ecology, College of Life Sciences, Wuhan University, Wuhan 430072, China
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11
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Cooper JC, Phadnis N. Parallel Evolution of Sperm Hyper-Activation Ca2+ Channels. Genome Biol Evol 2017; 9:1938-1949. [PMID: 28810709 PMCID: PMC5553355 DOI: 10.1093/gbe/evx131] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2017] [Indexed: 01/06/2023] Open
Abstract
Sperm hyper-activation is a dramatic change in sperm behavior where mature sperm burst into a final sprint in the race to the egg. The mechanism of sperm hyper-activation in many metazoans, including humans, consists of a jolt of Ca2+ into the sperm flagellum via CatSper ion channels. Surprisingly, all nine CatSper genes have been independently lost in several animal lineages. In Drosophila, sperm hyper-activation is performed through the cooption of the polycystic kidney disease 2 (pkd2) Ca2+ channel. The parallels between CatSpers in primates and pkd2 in Drosophila provide a unique opportunity to examine the molecular evolution of the sperm hyper-activation machinery in two independent, nonhomologous calcium channels separated by > 500 million years of divergence. Here, we use a comprehensive phylogenomic approach to investigate the selective pressures on these sperm hyper-activation channels. First, we find that the entire CatSper complex evolves rapidly under recurrent positive selection in primates. Second, we find that pkd2 has parallel patterns of adaptive evolution in Drosophila. Third, we show that this adaptive evolution of pkd2 is driven by its role in sperm hyper-activation. These patterns of selection suggest that the evolution of the sperm hyper-activation machinery is driven by sexual conflict with antagonistic ligands that modulate channel activity. Together, our results add sperm hyper-activation channels to the class of fast evolving reproductive proteins and provide insights into the mechanisms used by the sexes to manipulate sperm behavior.
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12
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Bennison C, Hemmings N, Brookes L, Slate J, Birkhead T. Sperm morphology, adenosine triphosphate (ATP) concentration and swimming velocity: unexpected relationships in a passerine bird. Proc Biol Sci 2017; 283:rspb.2016.1558. [PMID: 27559067 PMCID: PMC5013805 DOI: 10.1098/rspb.2016.1558] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/02/2016] [Indexed: 11/21/2022] Open
Abstract
The relationship between sperm energetics and sperm function is poorly known, but is central to our understanding of the evolution of sperm traits. The aim of this study was to examine how sperm morphology and ATP content affect sperm swimming velocity in the zebra finch Taeniopygia guttata. We exploited the high inter-male variation in this species and created extra experimental power by increasing the number of individuals with very long or short sperm through artificial selection. We found a pronounced quadratic relationship between total sperm length and swimming velocity, with velocity increasing with length up to a point, but declining in the very longest sperm. We also found an unexpected negative association between midpiece length and ATP content: sperm with a short midpiece generally contained the highest concentration of ATP. Low intracellular ATP is therefore unlikely to explain reduced swimming velocity among the very longest sperm (which tend to have a shorter midpiece).
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Affiliation(s)
- Clair Bennison
- Department of Animal and Plant Sciences, The University of Sheffield, Alfred Denny Building, Western Bank, Sheffield, UK
| | - Nicola Hemmings
- Department of Animal and Plant Sciences, The University of Sheffield, Alfred Denny Building, Western Bank, Sheffield, UK
| | - Lola Brookes
- Department of Animal and Plant Sciences, The University of Sheffield, Alfred Denny Building, Western Bank, Sheffield, UK Zoological Society of London, London, UK
| | - Jon Slate
- Department of Animal and Plant Sciences, The University of Sheffield, Alfred Denny Building, Western Bank, Sheffield, UK
| | - Tim Birkhead
- Department of Animal and Plant Sciences, The University of Sheffield, Alfred Denny Building, Western Bank, Sheffield, UK
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13
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Liao WB, Huang Y, Zeng Y, Zhong MJ, Luo Y, Lüpold S. Ejaculate evolution in external fertilizers: Influenced by sperm competition or sperm limitation? Evolution 2017; 72:4-17. [PMID: 28975611 DOI: 10.1111/evo.13372] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/22/2017] [Accepted: 09/26/2017] [Indexed: 12/19/2022]
Abstract
The evolution of sperm quality and quantity is shaped by various selective processes, with sperm competition generally considered the primary selective agent. Particularly in external fertilizers, however, sperm limitation through gamete dispersal can also influence gamete investments, but empirical data examining this effect are limited. Here, we studied the relative importance of sperm competition and the spawning conditions in explaining the macroevolutionary patterns of sperm size and number within two taxa with external fertilization but differences in their reproductive biology. In frogs, sperm swim slowly but for up to hours as they penetrate the gelatinous egg coating, whereas fish sperm typically swim fast, are very short-lived (seconds to minutes), and often face a relatively higher risk of being moved away from the ova by currents. Our phylogenetic models and path analyses revealed different trajectories of ejaculate evolution in these two taxa. Sperm size and number responded primarily to variation in sperm competition in the anurans, but more strongly to egg number and water turbulence in the fishes. Whereas the results across anurans align with the general expectation that sexual selection is the main driver of ejaculate evolution, our findings across the fishes suggest that sperm limitation has been underappreciated.
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Affiliation(s)
- Wen Bo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, Sichuan, China
| | - Yan Huang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, Sichuan, China
| | - Yu Zeng
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, Sichuan, China
| | - Mao Jun Zhong
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, Sichuan, China
| | - Yi Luo
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, Sichuan, China
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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14
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Godwin JL, Vasudeva R, Michalczyk Ł, Martin OY, Lumley AJ, Chapman T, Gage MJG. Experimental evolution reveals that sperm competition intensity selects for longer, more costly sperm. Evol Lett 2017; 1:102-113. [PMID: 30283643 PMCID: PMC6089504 DOI: 10.1002/evl3.13] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/24/2017] [Accepted: 05/02/2017] [Indexed: 12/12/2022] Open
Abstract
It is the differences between sperm and eggs that fundamentally underpin the differences between the sexes within reproduction. For males, it is theorized that widespread sperm competition leads to selection for investment in sperm numbers, achieved by minimizing sperm size within limited resources for spermatogenesis in the testis. Here, we empirically examine how sperm competition shapes sperm size, after more than 77 generations of experimental selection of replicate lines under either high or low sperm competition intensities in the promiscuous flour beetle Tribolium castaneum. After this experimental evolution, populations had diverged significantly in their sperm competitiveness, with sperm in ejaculates from males evolving under high sperm competition intensities gaining 20% greater paternity than sperm in ejaculates from males that had evolved under low sperm competition intensity. Males did not change their relative investment into sperm production following this experimental evolution, showing no difference in testis sizes between high and low intensity regimes. However, the more competitive males from high sperm competition intensity regimes had evolved significantly longer sperm and, across six independently selected lines, there was a significant association between the degree of divergence in sperm length and average sperm competitiveness. To determine whether such sperm elongation is costly, we used dietary restriction experiments, and revealed that protein-restricted males produced significantly shorter sperm. Our findings therefore demonstrate that sperm competition intensity can exert positive directional selection on sperm size, despite this being a costly reproductive trait.
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Affiliation(s)
- Joanne L. Godwin
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUnited Kingdom
| | - Ramakrishnan Vasudeva
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUnited Kingdom
| | | | | | - Alyson J. Lumley
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUnited Kingdom
| | - Tracey Chapman
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUnited Kingdom
| | - Matthew J. G. Gage
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUnited Kingdom
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15
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McDiarmid CS, Friesen CR, Ballen C, Olsson M. Sexual coloration and sperm performance in the Australian painted dragon lizard,
Ctenophorus pictus. J Evol Biol 2017; 30:1303-1312. [DOI: 10.1111/jeb.13092] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/12/2017] [Indexed: 12/16/2022]
Affiliation(s)
- C. S. McDiarmid
- School of Life and Environmental Sciences University of Sydney Sydney NSW Australia
| | - C. R. Friesen
- School of Life and Environmental Sciences University of Sydney Sydney NSW Australia
| | - C. Ballen
- College of Biological Sciences University of Minnesota Minneapolis MN USA
| | - M. Olsson
- Department of Biological and Environmental Sciences Göteborg University Göteborg Sweden
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16
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Lehnert SJ, Butts IAE, Flannery EW, Peters KM, Heath DD, Pitcher TE. Effects of ovarian fluid and genetic differences on sperm performance and fertilization success of alternative reproductive tactics in Chinook salmon. J Evol Biol 2017; 30:1236-1245. [PMID: 28387056 DOI: 10.1111/jeb.13088] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 03/03/2017] [Accepted: 03/30/2017] [Indexed: 12/20/2022]
Abstract
In many species, sperm velocity affects variation in the outcome of male competitive fertilization success. In fishes, ovarian fluid (OF) released with the eggs can increase male sperm velocity and potentially facilitate cryptic female choice for males of specific phenotypes and/or genotypes. Therefore, to investigate the effect of OF on fertilization success, we measured sperm velocity and conducted in vitro competitive fertilizations with paired Chinook salmon (Oncorhynchus tshawytscha) males representing two alternative reproductive tactics, jacks (small sneaker males) and hooknoses (large guarding males), in the presence of river water alone and OF mixed with river water. To determine the effect of genetic differences on fertilization success, we genotyped fish at neutral (microsatellites) and functional [major histocompatibility complex (MHC) II ß1] markers. We found that when sperm were competed in river water, jacks sired significantly more offspring than hooknoses; however, in OF, there was no difference in paternity between the tactics. Sperm velocity was significantly correlated with paternity success in river water, but not in ovarian fluid. Paternity success in OF, but not in river water alone, was correlated with genetic relatedness between male and female, where males that were less related to the female attained greater paternity. We found no relationship between MHC II ß1 divergence between mates and paternity success in water or OF. Our results indicate that OF can influence the outcome of sperm competition in Chinook salmon, where OF provides both male tactics with fertilization opportunities, which may in part explain what maintains both tactics in nature.
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Affiliation(s)
- S J Lehnert
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada
| | - I A E Butts
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, USA
| | - E W Flannery
- Department of Biological Sciences, University of Windsor, Windsor, ON, Canada
| | - K M Peters
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada.,Department of Biological Sciences, University of Windsor, Windsor, ON, Canada
| | - D D Heath
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada.,Department of Biological Sciences, University of Windsor, Windsor, ON, Canada
| | - T E Pitcher
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada.,Department of Biological Sciences, University of Windsor, Windsor, ON, Canada
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17
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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] [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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18
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Lymbery RA, Kennington WJ, Evans JP. Fluorescent sperm offer a method for tracking the real-time success of ejaculates when they compete to fertilise eggs. Sci Rep 2016; 6:22689. [PMID: 26941059 PMCID: PMC4778040 DOI: 10.1038/srep22689] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 02/17/2016] [Indexed: 12/25/2022] Open
Abstract
Despite intensive research effort, many uncertainties remain in the field of gamete-level sexual selection, particularly in understanding how sperm from different males interact when competing for fertilisations. Here, we demonstrate the utility of broadcast spawning marine invertebrates for unravelling these mysteries, highlighting their mode of reproduction and, in some species, unusual patterns of mitochondrial inheritance. We present a method utilising both properties in the blue mussel, Mytilus galloprovincialis. In mytilids and many other bivalves, both sperm and egg mitochondria are inherited. We exploit this, using the vital mitochondrial dye MitoTracker, to track the success of sperm from individual males when they compete with those from rivals to fertilise eggs. We confirm that dying mitochondria has no adverse effects on in vitro measures of sperm motility (reflecting mitochondrial energetics) or sperm competitive fertilisation success. Therefore, we propose the technique as a powerful and logistically tractable tool for sperm competition studies. Importantly, our method allows the competitive fertilisation success of sperm from any male to be measured directly and disentangled from confounding effects of post-fertilisation embryo survival. Moreover, the mitochondrial dye has broader applications in taxa without paternal mitochondrial inheritance, for example by tracking the dynamics of competing ejaculates prior to fertilisation.
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Affiliation(s)
- Rowan A Lymbery
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley 6009, WA, Australia
| | - W Jason Kennington
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley 6009, WA, Australia
| | - Jonathan P Evans
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley 6009, WA, Australia
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19
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Stewart KA, Wang R, Montgomerie R. Extensive variation in sperm morphology in a frog with no sperm competition. BMC Evol Biol 2016; 16:29. [PMID: 26832366 PMCID: PMC4735968 DOI: 10.1186/s12862-016-0601-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/25/2016] [Indexed: 11/18/2022] Open
Abstract
Background Recent comparative studies of several taxa have found that within-species variation in sperm size decreases with increasing levels of sperm competition, suggesting that male-male gamete competition selects for an optimal sperm phenotype. Previous studies of intraspecific sperm length variation have all involved internal fertilizers where some other factors—e.g., sperm storage and sperm movement along the walls of the female’s reproductive tract—probably also influence and reduce sperm size variation. Thus external fertilizers, where those factors are absent, might be expected to exhibit even more variation when there is little or no sperm competition. To test that idea, we studied the sperm morphology of a North American chorus frog, the spring peeper (Pseudacris crucifer), a species in which males encounter little or no sperm competition. Results As expected, sperm size was highly variable in the spring peeper, largely due to variation in flagellum length within and among individual males, among populations and between mitochondrial lineages in southwestern Ontario. In addition, a large proportion of spermatozoa in all males was abnormal in such a way that the ability of abnormal spermatozoa to fertilize was probably compromised. There were no differences in the frequencies of abnormalities among populations or mitochondrial lineages. Conclusions In the absence of sperm competition, we suggest that genetic drift has probably played a role in the generation of diversity in sperm morphology in this species, potentially resulting in the observed differences among populations. Such interpopulation difference in sperm morphology might be expected to increase the degree of reproductive isolation between populations even before other isolating mechanisms evolve. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0601-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kathryn A Stewart
- Department of Biology, Queen's University, Kingston, ON, K7L 3N6, Canada. .,College of Environmental Science and Engineering, Tongji University, Shanghai, 1239 Siping Rd, P R China.
| | - Rachel Wang
- Department of Biology, Queen's University, Kingston, ON, K7L 3N6, Canada.
| | - Robert Montgomerie
- Department of Biology, Queen's University, Kingston, ON, K7L 3N6, Canada.
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20
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Byrne PG, Dunne C, Munn AJ, Silla AJ. Environmental osmolality influences sperm motility activation in an anuran amphibian. J Evol Biol 2015; 28:521-34. [PMID: 25586700 DOI: 10.1111/jeb.12584] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 12/23/2014] [Accepted: 01/08/2015] [Indexed: 02/01/2023]
Abstract
Evolutionary theory predicts that selection will favour sperm traits that maximize fertilization success in local fertilization environments. In externally fertilizing species, osmolality of the fertilization medium is known to play a critical role in activating sperm motility, but there remains limited evidence for adaptive responses to local osmotic environments. In this study, we used a split-sample experimental design and computer-assisted sperm analysis to (i) determine the optimal medium osmolality for sperm activation (% sperm motility and sperm velocity) in male common eastern froglets (Crinia signifera), (ii) test for among-population variation in percentage sperm motility and sperm velocity at various activation-medium osmolalities and (iii) test for among-population covariation between sperm performance and environmental osmolality. Frogs were obtained from nine populations that differed in environmental osmolality, and sperm samples of males from different populations were subjected to a range of activation-medium osmolalities. Percentage sperm motility was optimal between 10 and 50 mOsm kg(-1) , and sperm velocity was optimal between 10 and 100 mOsm kg(-1) , indicating that C. signifera has evolved sperm that can function across a broad range of osmolalities. As predicted, there was significant among-population variation in sperm performance. Furthermore, there was a significant interaction between activation-medium osmolality and environmental osmolality, indicating that frogs from populations with higher environmental osmolality produced sperm that performed better at higher osmolalities in vitro. This finding may reflect phenotypic plasticity in sperm functioning, or genetic divergence resulting from spatial variation in the strength of directional selection. Both of these explanations are consistent with evolutionary theory, providing some of the first empirical evidence that local osmotic environments can favour adaptive sperm motility responses in species that use an external mode of fertilization.
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Affiliation(s)
- P G Byrne
- The Institute for Conservation Biology and Environmental Management, School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
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21
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Browne R, Kaurova S, Uteshev V, Shishova N, McGinnity D, Figiel C, Mansour N, Agnew D, Wu M, Gakhova E, Dzyuba B, Cosson J. Sperm motility of externally fertilizing fish and amphibians. Theriogenology 2015; 83:1-13. [DOI: 10.1016/j.theriogenology.2014.09.018] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 09/08/2014] [Accepted: 09/11/2014] [Indexed: 12/15/2022]
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22
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Wilder AE, Welch AM. Effects of Salinity and Pesticide on Sperm Activity and Oviposition Site Selection in Green Treefrogs,Hyla cinerea. COPEIA 2014. [DOI: 10.1643/ce-14-053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Fitzpatrick JL, Evans JP. Postcopulatory inbreeding avoidance in guppies. J Evol Biol 2014; 27:2585-94. [PMID: 25387854 DOI: 10.1111/jeb.12545] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/22/2014] [Accepted: 10/23/2014] [Indexed: 01/18/2023]
Abstract
In many species, the negative fitness effects of inbreeding have facilitated the evolution of a wide range of inbreeding avoidance mechanisms. Although avoidance mechanisms operating prior to mating are well documented, evidence for postcopulatory mechanisms of inbreeding avoidance remain scarce. Here, we examine the potential for paternity biases to favour unrelated males when their sperm compete for fertilizations though postcopulatory inbreeding avoidance mechanisms in the guppy, Poecilia reticulata. To test this possibility, we used a series of artificial inseminations to deliver an equal number of sperm from a related (either full sibling or half sibling) and unrelated male to a female while statistically controlling for differences in sperm quality between rival ejaculates. In this way, we were able to focus exclusively on postcopulatory mechanisms of inbreeding avoidance and account for differences in sperm competitiveness between rival males. Under these carefully controlled conditions, we report a significant bias in paternity towards unrelated males, although this effect was only apparent when the related male was a full sibling. We also show that sperm competition generally favours males with highly viable sperm and thus that some variance in sperm competitiveness can be attributed to difference in sperm quality. Our findings for postcopulatory inbreeding avoidance are consistent with prior work on guppies, revealing that sperm competition success declines linearly with the level of relatedness, but also that such effects are only apparent at relatedness levels of full siblings or higher. These findings reveal that postcopulatory processes alone can facilitate inbreeding avoidance.
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Affiliation(s)
- J L Fitzpatrick
- Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester, UK; Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, WA, Australia
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24
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Fitzpatrick JL, Lüpold S. Sexual selection and the evolution of sperm quality. ACTA ACUST UNITED AC 2014; 20:1180-9. [DOI: 10.1093/molehr/gau067] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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25
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Johnson SL, Villarroel M, Rosengrave P, Carne A, Kleffmann T, Lokman PM, Gemmell NJ. Proteomic analysis of chinook salmon (Oncorhynchus tshawytscha) ovarian fluid. PLoS One 2014; 9:e104155. [PMID: 25089903 PMCID: PMC4121310 DOI: 10.1371/journal.pone.0104155] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 07/10/2014] [Indexed: 11/18/2022] Open
Abstract
The ovarian, or coelomic, fluid that is released with the egg mass of many fishes is increasingly found to play an important role in several biological processes crucial for reproductive success. These include maintenance of oocyte fertility and developmental competence, prolonging of sperm motility, and enhancing sperm swimming speed. Here we examined if and how the proteome of chinook salmon (Oncorhynchus tshawytscha) ovarian fluid varied among females and then sought to examine the composition of this fluid. Ovarian fluid in chinook salmon was analyzed using 1D SDS PAGE and LC-MS/MS tryptic digest screened against Mascot and Sequest databases. We found marked differences in the number and concentrations of proteins in salmon ovarian fluid across different females. A total of 174 proteins were identified in ovarian fluid, 47 of which were represented by six or more peptides, belonging to one of six Gene Ontology pathways. The response to chemical stimulus and response to hypoxia pathways were best represented, accounting for 26 of the 174 proteins. The current data set provides a resource that furthers our understanding of those factors that influence successful egg production and fertilisation in salmonids and other species.
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Affiliation(s)
- Sheri L. Johnson
- Allan Wilson Centre for Molecular Ecology and Evolution and Department of Anatomy, University of Otago, Dunedin, New Zealand
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Marsha Villarroel
- Allan Wilson Centre for Molecular Ecology and Evolution and Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Patrice Rosengrave
- Allan Wilson Centre for Molecular Ecology and Evolution and Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Alan Carne
- Centre for Protein Research, Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Torsten Kleffmann
- Centre for Protein Research, Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - P. Mark Lokman
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Neil J. Gemmell
- Allan Wilson Centre for Molecular Ecology and Evolution and Department of Anatomy, University of Otago, Dunedin, New Zealand
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26
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Zeng Y, Lou SL, Liao WB, Jehle R. Evolution of sperm morphology in anurans: insights into the roles of mating system and spawning location. BMC Evol Biol 2014; 14:104. [PMID: 24884745 PMCID: PMC4030069 DOI: 10.1186/1471-2148-14-104] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 05/02/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The degree of postcopulatory sexual selection, comprising variable degrees of sperm competition and cryptic female choice, is an important evolutionary force to influence sperm form and function. Here we investigated the effects of mating system and spawning location on the evolution of sperm morphology in 67 species of Chinese anurans. We also examined how relative testes size as an indicator of the level of sperm competition affected variation in sperm morphology across a subset of 29 species. RESULTS We found a significant association of mating system and spawning location with sperm morphology. However, when removing the effects of body mass or absolute testes mass for species for which such data were available, this effect became non-significant. Consistent with predictions from sperm competition theory, we found a positive correlation between sperm morphology and relative testes size after taking phylogeny into account. CONCLUSIONS Our findings suggest that sexual selection in Chinese anurans favors longer sperm when the level of sperm competition is high. Pre-copulatory male-male competition and spawning location, on the other hand, do not affect the evolution of sperm morphology after taking body mass and absolute testes mass into account.
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Affiliation(s)
- Yu Zeng
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, P. R. China
- China Three Gorges Corporation, Beijing 100038, China
| | - Shang Ling Lou
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, P. R. China
| | - Wen Bo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, P. R. China
| | - Robert Jehle
- School of Environment & Life Sciences, University of Salford, Salford M5 4WT, UK
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27
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Friesen CR, Squire MK, Mason RT. Intrapopulational variation of ejaculate traits and sperm depletion in red-sided garter snakes. J Zool (1987) 2014. [DOI: 10.1111/jzo.12092] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. R. Friesen
- Department of Zoology; Oregon State University; Corvallis OR USA
| | - M. K. Squire
- Department of Zoology; Oregon State University; Corvallis OR USA
- Department of Biology; Texas A&M University; College Station TX USA
| | - R. T. Mason
- Department of Zoology; Oregon State University; Corvallis OR USA
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28
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Bakker TCM, Hollmann M, Mehlis M, Zbinden M. Functional variation of sperm morphology in sticklebacks. Behav Ecol Sociobiol 2014. [DOI: 10.1007/s00265-013-1676-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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29
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Álvarez D, Viesca L, Nicieza AG. Sperm competitiveness differs between two frog populations with different breeding systems. J Zool (1987) 2013. [DOI: 10.1111/jzo.12093] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- D. Álvarez
- Ecology Unit Department of Organisms and Systems Biology University of Oviedo Oviedo Spain
- Research Unit of Biodiversity (UO‐CSIC‐PA) Mieres Spain
| | - L. Viesca
- Ecology Unit Department of Organisms and Systems Biology University of Oviedo Oviedo Spain
- Research Unit of Biodiversity (UO‐CSIC‐PA) Mieres Spain
| | - A. G. Nicieza
- Ecology Unit Department of Organisms and Systems Biology University of Oviedo Oviedo Spain
- Research Unit of Biodiversity (UO‐CSIC‐PA) Mieres Spain
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30
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Abstract
Hybrid male sterility is a common reproductive isolating barrier between species. Yet, little is known about the actual developmental causes of this phenomenon, especially in naturally hybridizing species. We sought to evaluate the developmental causes of hybrid male sterility, using spadefoot toads as our study system. Plains spadefoot toads (Spea bombifrons) and Mexican spadefoot toads (S. multiplicata) hybridize where they co-occur in the southwestern USA. Hybrids are viable, but hybrid males suffer reduced fertility. We compared testes size and developmental stages of sperm cell maturation between hybrid males and males of each species. We found that testes of hybrid males did not differ in mean size from pure-species males. However, hybrids showed a greater range of within-individual variation in testes size than pure-species males. Moreover, although hybrids produced similar numbers of early stage sperm cells, hybrids produced significantly fewer mature spermatozoids than pure-species males. Interestingly, an introgressed individual produced numbers of live sperm comparable to pure-species males, but the majority of these sperm cells were abnormally shaped and non-motile. These results indicate that hybrid incompatibilities in late sperm development serve as a reproductive isolating barrier between species. The nature of this breakdown highlights the possibilities that hybrid males may vary in fertility and that fertility could possibly be recovered in introgressed males.
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Affiliation(s)
- Lisa K. Wünsch
- Department of Animal Physiology, University of Tübingen, Auf der Morgenstelle 5, D-72076, Germany
- Department of Biology, CB# 3280, University of North Carolina, Chapel Hill, North Carolina 25799-3280, USA
| | - Karin S. Pfennig
- Department of Biology, CB# 3280, University of North Carolina, Chapel Hill, North Carolina 25799-3280, USA
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31
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Simpson JL, Humphries S, Evans JP, Simmons LW, Fitzpatrick JL. Relationships between sperm length and speed differ among three internally and three externally fertilizing species. Evolution 2013; 68:92-104. [PMID: 24224469 DOI: 10.1111/evo.12199] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 06/04/2013] [Indexed: 11/30/2022]
Abstract
It is often assumed that longer sperm, by virtue of their increased swimming speed, have a fertilization advantage over shorter sperm when in competition to fertilize eggs. However, there is surprisingly little evidence for a positive correlation between sperm length and speed. Here we use an approach that accounts for within-male variation in sperm traits to examine the relationships between sperm length and sperm speed across a broad range of species, including three internally fertilizing species and three externally fertilizing species. Our results reveal that correlations between sperm size and speed are indeed present and possibly more common than currently thought. However, the direction of the correlations between sperm length and speed, which are more prevalent within a male's ejaculate than among males, were influenced by fertilization mode in contrasting and unexpected ways. Broadly, the patterns revealed that in externally fertilizing species sperm with longer flagellum and shorter heads relative to their flagellum swam faster, whereas in internally fertilizing species sperm with shorter flagellum and longer heads relative to their flagellum swam faster. We discuss these results in light of sperm competition theory and contrast the intraspecific patterns observed in this study with macroevolutionary patterns of sperm evolution reported elsewhere.
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Affiliation(s)
- Julia L Simpson
- Physical Ecology Group, School of Biological, Biomedical and Environmental Sciences, The University of Hull, Kingston-upon-Hull, HU6 7RX, United Kingdom
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32
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Female mediation of competitive fertilization success in Drosophila melanogaster. Proc Natl Acad Sci U S A 2013; 110:10693-8. [PMID: 23757499 DOI: 10.1073/pnas.1300954110] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
How females store and use sperm after remating can generate postcopulatory sexual selection on male ejaculate traits. Variation in ejaculate performance traits generally is thought to be intrinsic to males but is likely to interact with the environment in which sperm compete (e.g., the female reproductive tract). Our understanding of female contributions to competitive fertilization success is limited, however, in part because of the challenges involved in observing events within the reproductive tract of internally fertilizing species while discriminating among sperm from competing males. Here, we used females from crosses among isogenic lines of Drosophila melanogaster, each mated to two genetically standardized males (the first with green- and the second with red-tagged sperm heads) to demonstrate heritable variation in female remating interval, progeny production rate, sperm-storage organ morphology, and a number of sperm performance, storage, and handling traits. We then used multivariate analyses to examine relationships between this female-mediated variation and competitive paternity. In particular, the timing of female ejection of excess second-male and displaced first-male sperm was genetically variable and, by terminating the process of sperm displacement, significantly influenced the relative numbers of sperm from each male competing for fertilization, and consequently biased paternity. Our results demonstrate that females do not simply provide a static arena for sperm competition but rather play an active and pivotal role in postcopulatory processes. Resolving the adaptive significance of genetic variation in female-mediated mechanisms of sperm handling is critical for understanding sexual selection, sexual conflict, and the coevolution of male and female reproductive traits.
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33
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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: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [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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34
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Mautz BS, Møller AP, Jennions MD. Do male secondary sexual characters signal ejaculate quality? A meta-analysis. Biol Rev Camb Philos Soc 2013; 88:669-82. [PMID: 23374138 DOI: 10.1111/brv.12022] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 12/20/2012] [Accepted: 01/07/2013] [Indexed: 12/23/2022]
Abstract
There are two reasons why researchers are interested in the phenotypic relationship between the expression of male secondary sexual characters (SSCs) and 'ejaculate quality' (defined as sperm/ejaculate traits that are widely assumed to increase female fertility and/or sperm competitiveness). First, if the relationship is positive then females could gain a direct benefit by choosing more attractive males for fertility assurance reasons ('the phenotype-linked fertility' hypothesis). Second, there is much interest in the direction of the correlation between traits favoured by pre-copulatory sexual selection (i.e. affecting mating success) and those favoured by post-copulatory sexual selection (i.e. increasing sperm competitiveness). If the relationship is negative this could lead to the two forms of selection counteracting each other. Theory predicts that the direction of the relationship could be either positive or negative depending on the underlying genetic variance and covariance in each trait, the extent of variation among males in condition (resources available to allocate to reproductive traits), and variation among males in the cost or rate of mating. We conducted a meta-analysis to determine the average relationship between the expression of behavioural and morphological male secondary sexual characters and four assays of ejaculate quality (sperm number, viability, swimming speed and size). Regardless of how the data were partitioned the mean relationship was consistently positive, but always statistically non-significant. The only exception was that secondary sexual character expression was weakly but significantly positively correlated with sperm viability (r = 0.07, P < 0.05). There was no significant difference in the strength or direction of the relationship between behavioural and morphological SSCs, nor among relationships using the four ejaculate quality assays. The implications of our findings are discussed.
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Affiliation(s)
- Brian S Mautz
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
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35
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Hettyey A, Vági B, Penn DJ, Hoi H, Wagner RH. Post-meiotic intra-testicular sperm senescence in a wild vertebrate. PLoS One 2012; 7:e50820. [PMID: 23226542 PMCID: PMC3513296 DOI: 10.1371/journal.pone.0050820] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 10/29/2012] [Indexed: 11/24/2022] Open
Abstract
There is growing interest in sperm senescence, both in its underlying mechanisms and evolutionary consequences, because it can impact the evolution of numerous life history traits. Previous studies have documented various types of sperm senescence, but evidence of post-meiotic intra-testicular sperm senescence in wild animals is lacking. To assess such senescence, we studied within-season changes in sperm motility in the common toad (Bufo bufo), where males produce all sperm prior to the breeding season. We found that males exposed to experimentally induced re-hibernation at the start of the breeding season, that is to experimentally lowered metabolic rates, stored sperm of significantly higher motility than males that were kept under seminatural conditions without females throughout the breeding season. This finding indicates that re-hibernation slows normal rates of sperm ageing and constitutes the first evidence to our knowledge of post-meiotic intra-testicular sperm senescence in a wild vertebrate. We also found that in males kept in seminatural conditions, sperm motility was positively related to the number of matings a male achieved. Thus, our results suggest that post-meiotic intra-testicular sperm senescence does not have a genetically fixed rate and may be modulated by temperature and possibly by mating opportunities.
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Affiliation(s)
- Attila Hettyey
- Department of Integrative Biology and Evolution, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria.
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36
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Sasson DA, Johnson SL, Brockmann HJ. The role of age on sperm traits in the American horseshoe crab, Limulus polyphemus. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2012.07.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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37
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Lüpold S, Birkhead TR, Westneat DF. Seasonal variation in ejaculate traits of male red-winged blackbirds (Agelaius phoeniceus). Behav Ecol Sociobiol 2012. [DOI: 10.1007/s00265-012-1415-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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38
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Abstract
Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected to shape male expenditure on the ejaculate. Here, we review empirical data that illustrate the evolutionary consequences of sperm competition. Sperm competition favors the evolution of increased testes size and sperm production. In some species, males appear capable of adjusting the number of sperm ejaculated, depending on the perceived levels of sperm competition. Selection is also expected to act on sperm form and function, although the evidence for this remains equivocal. Comparative studies suggest that sperm length and swimming speed may increase in response to selection from sperm competition. However, the mechanisms driving this pattern remain unclear. Evidence that sperm length influences sperm swimming speed is mixed and fertilization trials performed across a broad range of species demonstrate inconsistent relationships between sperm form and function. This ambiguity may in part reflect the important role that seminal fluid proteins (sfps) play in affecting sperm function. There is good evidence that sfps are subject to selection from sperm competition, and recent work is pointing to an ability of males to adjust their seminal fluid chemistry in response to sperm competition from rival males. We argue that future research must consider sperm and seminal fluid components of the ejaculate as a functional unity. Research at the genomic level will identify the genes that ultimately control male fertility.
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Affiliation(s)
- Leigh W Simmons
- Centre for Evolutionary Biology, , School of Animal Biology (M092), The University of Western Australia, Crawley, Western Australia 6009, Australia.
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39
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Lüpold S, Manier MK, Berben KS, Smith KJ, Daley BD, Buckley SH, Belote JM, Pitnick S. How multivariate ejaculate traits determine competitive fertilization success in Drosophila melanogaster. Curr Biol 2012; 22:1667-72. [PMID: 22840512 DOI: 10.1016/j.cub.2012.06.059] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 05/18/2012] [Accepted: 06/21/2012] [Indexed: 11/19/2022]
Abstract
Success in sperm competition, occurring whenever females mate with multiple males, is predicted to be influenced by variation in ejaculate quality and interactions among competing sperm. Yet, apart from sperm number, relevant ejaculate characteristics and sperm-sperm interactions are poorly understood, particularly within a multivariate framework and the natural selective environment of the female reproductive tract. Here, we used isogenic lines of Drosophila melanogaster with distinguishable sperm to demonstrate and partition genetic variation in multiple sperm quality and performance traits. Next, by competing males from different lines, we show how rival sperm significantly influence each other's velocity and reveal that males with relatively slow and/or long sperm better displace rival sperm and resist displacement, thus avoiding ejection by the female from her reproductive tract. Finally, we establish fitness consequences of genetic variation in sperm quality and its role in securing a numerical advantage in storage by showing that offspring paternity is determined strictly by the representation of stored, competing sperm. These results provide novel insight into complex postcopulatory processes, illustrate that different ejaculate traits are critical at different biologically relevant time-points, and provide a critical foundation for elucidating the role of postcopulatory sexual selection in trait diversification and speciation.
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Affiliation(s)
- Stefan Lüpold
- Department of Biology, Syracuse University, Syracuse, NY 13244-1270, USA.
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40
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Mi ZP, Liao WB, Jin L, Lou SL, Cheng J, Wu H. Testis Asymmetry and Sperm Length inRhacophorus omeimontis. Zoolog Sci 2012; 29:368-72. [DOI: 10.2108/zsj.29.368] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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41
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Fitzpatrick JL, Simmons LW, Evans JP. Complex patterns of multivariate selection on the ejaculate of a broadcast spawning marine invertebrate. Evolution 2012; 66:2451-60. [PMID: 22834744 DOI: 10.1111/j.1558-5646.2012.01627.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Assessing how selection operates on several, potentially interacting, components of the ejaculate is a challenging endeavor. Ejaculates can be subject to natural and/or sexual selection, which can impose both linear (directional) and nonlinear (stabilizing, disruptive, and correlational) selection on different ejaculate components. Most previous studies have examined linear selection of ejaculate components and, consequently, we know very little about patterns of nonlinear selection on the ejaculate. Even less is known about how selection acts on the ejaculate as a functionally integrated unit, despite evidence of covariance among ejaculate components. Here, we assess how selection acts on multiple ejaculate components simultaneously in the broadcast spawning sessile invertebrate Mytilus galloprovincialis using the statistical tools of multivariate selection analyses. Our analyses of relative fertilization rates revealed complex patterns of selection on sperm velocity, motility, and morphology. Interestingly, the most successful ejaculates were made up of slower swimming sperm with relatively low percentages of motile cells, and sperm with smaller head volumes that swam in highly pronounced curved swimming trajectories. These results are consistent with an emerging body of literature on fertilization kinetics in broadcast spawners, and shed light on the fundamental nature of selection acting on the ejaculate as a functionally integrated unit.
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Affiliation(s)
- John L Fitzpatrick
- Centre for Evolutionary Biology, School of Animal Biology, M092, University of Western Australia, WA 6009, Australia.
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42
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Smith CC. Opposing effects of sperm viability and velocity on the outcome of sperm competition. Behav Ecol 2012. [DOI: 10.1093/beheco/ars036] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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43
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Simmons LW, Peters M, Rhodes G. Low pitched voices are perceived as masculine and attractive but do they predict semen quality in men? PLoS One 2011; 6:e29271. [PMID: 22216228 PMCID: PMC3244455 DOI: 10.1371/journal.pone.0029271] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 11/23/2011] [Indexed: 11/18/2022] Open
Abstract
Women find masculinity in men's faces, bodies, and voices attractive, and women's preferences for men's masculine features are thought to be biological adaptations for finding a high quality mate. Fertility is an important aspect of mate quality. Here we test the phenotype-linked fertility hypothesis, which proposes that male secondary sexual characters are positively related to semen quality, allowing females to obtain direct benefits from mate choice. Specifically, we examined women's preferences for men's voice pitch, and its relationship with men's semen quality. Consistent with previous voice research, women judged lower pitched voices as more masculine and more attractive. However men with lower pitched voices did not have better semen quality. On the contrary, men whose voices were rated as more attractive tended to have lower concentrations of sperm in their ejaculate. These data are more consistent with a trade off between sperm production and male investment in competing for and attracting females, than with the phenotype-linked fertility hypothesis.
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Affiliation(s)
- Leigh W Simmons
- Centre for Evolutionary Biology, School of Animal Biology (M092), University of Western Australia, Crawley, Western Australia, Australia.
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44
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Roberts JD, Byrne PG. Polyandry, Sperm Competition, and the Evolution of Anuran Amphibians. ADVANCES IN THE STUDY OF BEHAVIOR 2011. [DOI: 10.1016/b978-0-12-380896-7.00001-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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45
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Sperm number and velocity affect sperm competition success in the guppy (Poecilia reticulata). Behav Ecol Sociobiol 2010. [DOI: 10.1007/s00265-010-1085-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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46
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Dziminski MA, Roberts JD, Beveridge M, Simmons LW. Among-population covariation between sperm competition and ejaculate expenditure in frogs. Behav Ecol 2010. [DOI: 10.1093/beheco/arp191] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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