1
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Blais BR, Wells SA, Poynter BM, Harris TR, Allard RA, Koprowski JL. Bridging conservation across the ex situ‐in situ spectrum: Insights into the reproductive ecology of the threatened narrow‐headed gartersnake (
Thamnophis rufipunctatus
). Zoo Biol 2022; 42:429-439. [DOI: 10.1002/zoo.21747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 10/28/2022] [Accepted: 12/03/2022] [Indexed: 12/24/2022]
Affiliation(s)
- Brian R. Blais
- School of Natural Resources and the Environment University of Arizona Tucson Arizona USA
| | - Stuart A. Wells
- School of Natural Resources and the Environment University of Arizona Tucson Arizona USA
- Department of Conservation and Science Arizona Center for Nature Conservation/Phoenix Zoo Phoenix Arizona USA
| | - Bradley M. Poynter
- Department of Conservation and Science Arizona Center for Nature Conservation/Phoenix Zoo Phoenix Arizona USA
| | - Tara R. Harris
- Department of Conservation and Science Arizona Center for Nature Conservation/Phoenix Zoo Phoenix Arizona USA
| | - Ruth A. Allard
- Department of Conservation and Science Arizona Center for Nature Conservation/Phoenix Zoo Phoenix Arizona USA
| | - John L. Koprowski
- School of Natural Resources and the Environment University of Arizona Tucson Arizona USA
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2
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Friesen CR, Uhrig EJ, Mason RT. Dehydrated males are less likely to dive into the mating pool. Behav Ecol 2021. [DOI: 10.1093/beheco/arab151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Abstract
The hydration state of animals vying for reproductive success may have implications for the tempo and mode of sexual selection, which may be salient in populations that experience increasing environmental fluctuations in water availability. Using red-sided garter snakes as a model system, we tested the effect of water supplementation on courtship, mating behavior, and copulatory plug (CP) production during a drought year. Over 3 days of mating trials, water-supplemented males (WET males, n = 45) outperformed a control group that was not supplemented with water (DRY males, n = 45). Over 70% of WET males mated but just 33% of DRY males did so. As a group, WET males mated 79 times versus 28 times by DRY males. On the last day of mating trials, over 70% of WET males were still courting, with 19 of them mating, whereas less than 25% of DRY males were courting and only one mated. CP deposition accounted for 4–6% of the mass lost by mating males, but hydration did not affect CP mass or water content. These findings suggest that, in years of low water availability, the number of courting males and the intensity of their courtship declines, thereby affecting sexual selection and conflict, at least within that year.
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Affiliation(s)
- Christopher R Friesen
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Building 35, Northfields Avenue, Wollongong, NSW 2522, Australia
- Department of Integrative Biology, Oregon State University, 3029 Cordley Hall, Corvallis, OR 97331, USA
- School of Life and Environmental Sciences, Bldg F22, Life Earth and Environmental Sciences (LEES) Building, The University of Sydney, Camperdown, NSW 2006, Australia
| | - Emily J Uhrig
- Department of Integrative Biology, Oregon State University, 3029 Cordley Hall, Corvallis, OR 97331, USA
- Center for Research on Sustainable Forests, University of Maine, 5755 Nutting Hall, Room 263, Orono, ME 04469, USA
| | - Robert T Mason
- Department of Integrative Biology, Oregon State University, 3029 Cordley Hall, Corvallis, OR 97331, USA
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3
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Harrison LM, Noble DWA, Jennions MD. A meta-analysis of sex differences in animal personality: no evidence for the greater male variability hypothesis. Biol Rev Camb Philos Soc 2021; 97:679-707. [PMID: 34908228 DOI: 10.1111/brv.12818] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 11/13/2021] [Accepted: 11/17/2021] [Indexed: 12/18/2022]
Abstract
The notion that men are more variable than women has become embedded into scientific thinking. For mental traits like personality, greater male variability has been partly attributed to biology, underpinned by claims that there is generally greater variation among males than females in non-human animals due to stronger sexual selection on males. However, evidence for greater male variability is limited to morphological traits, and there is little information regarding sex differences in personality-like behaviours for non-human animals. Here, we meta-analysed sex differences in means and variances for over 2100 effects (204 studies) from 220 species (covering five broad taxonomic groups) across five personality traits: boldness, aggression, activity, sociality and exploration. We also tested if sexual size dimorphism, a proxy for sex-specific sexual selection, explains variation in the magnitude of sex differences in personality. We found no significant differences in personality between the sexes. In addition, sexual size dimorphism did not explain variation in the magnitude of the observed sex differences in the mean or variance in personality for any taxonomic group. In sum, we find no evidence for widespread sex differences in variability in non-human animal personality.
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Affiliation(s)
- Lauren M Harrison
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, ACT, 2600, Australia
| | - Daniel W A Noble
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, ACT, 2600, Australia
| | - Michael D Jennions
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, ACT, 2600, Australia
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4
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Gangloff EJ, Manes MB, Schwartz TS, Robert KA, Huebschman N, Bronikowski AM. Multiple paternity in garter snakes with evolutionarily divergent life-histories. J Hered 2021; 112:508-518. [PMID: 34351393 PMCID: PMC8558580 DOI: 10.1093/jhered/esab043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 08/04/2021] [Indexed: 11/25/2022] Open
Abstract
Many animal species exhibit multiple paternity, defined as multiple males genetically contributing to a single female reproductive event, such as a clutch or litter. Although this phenomenon is well documented across a broad range of taxa, the underlying causes and consequences remain poorly understood. For example, it is unclear how multiple paternity correlates with life-history strategies. Furthermore, males and females may differ in mating strategies and these patterns may shift with ecological context and life-history variation. Here, we take advantage of natural life-history variation in garter snakes (Thamnophis elegans) to address these questions in a robust field setting where populations have diverged along a slow-to-fast life-history continuum. We determine both female (observed) and male (using molecular markers) reproductive success in replicate populations of 2 life-history strategies. We find that despite dramatic differences in annual female reproductive output: 1) females of both life-history ecotypes average 1.5 sires per litter and equivalent proportions of multiply-sired litters, whereas 2) males from the slow-living ecotype experience greater reproductive skew and greater variance in reproductive success relative to males from the fast-living ecotype males despite having equivalent average reproductive success. Together, these results indicate strong intrasexual competition among males, particularly in the fast-paced life-history ecotype. We discuss these results in the context of competing hypotheses for multiple paternity related to population density, resource variability, and life-history strategy.
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Affiliation(s)
- Eric J Gangloff
- Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA.,Department of Zoology, Ohio Wesleyan University, Delaware, OH USA
| | - Megan B Manes
- Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA
| | - Tonia S Schwartz
- Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA.,Deptartment of Biological Sciences, Auburn University, Auburn, AL 36849 USA
| | - Kylie A Robert
- Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA.,Deptartment of Ecology, Environment & Evolution, La Trobe University, Bundoora, Victoria 3086 Australia
| | | | - Anne M Bronikowski
- Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA
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5
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Exceptional long-term sperm storage by a female vertebrate. PLoS One 2021; 16:e0252049. [PMID: 34086677 PMCID: PMC8177532 DOI: 10.1371/journal.pone.0252049] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/10/2021] [Indexed: 11/19/2022] Open
Abstract
Females of many vertebrate species have the capacity to store sperm within their reproductive tracts for prolonged periods of time. Termed long-term sperm storage, this phenomenon has many important physiological, ecological, and evolutionary implications, particularly to the study of mating systems, including male reproductive success and post-copulatory sexual selection. Reptiles appear particularly predisposed to long-term sperm storage, with records in most major lineages, with a strong emphasis on turtles and squamates (lizards, snakes, but not the amphisbaenians). Because facultative parthenogenesis is a competing hypothesis to explain the production of offspring after prolonged separation from males, the identification of paternal alleles through genetic analysis is essential. However, few studies in snakes have undertaken this. Here, we report on a wild-collected female Western Diamond-backed Rattlesnake, Crotalus atrox, maintained in isolation from the time of capture in September 1999, that produced two healthy litters approximately one and six years post capture. Genetic analysis of the 2005 litter, identified paternal contribution in all offspring, thus rejecting facultative parthenogenesis. We conclude that the duration of long-term sperm storage was approximately 6 years (71 months), making this the longest period over which a female vertebrate has been shown to store sperm that resulted in the production of healthy offspring.
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6
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Friesen CR, Mason RT, Uhrig EJ. Postcopulatory sexual selection as a driver of sex- and population-specific kidney mass in garter snakes? Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
In lizards and snakes, the kidneys produce seminal fluid in addition to having osmoregulatory functions. Therefore, in response to polyandry, kidney mass should be under selection regimes such as those influencing testes. Male red-sided garter snakes deposit a kidney-derived copulatory plug that functions in sperm competition. We first tested for intersexual differences in kidney mass and allometry in one population and found that males had kidneys twice as heavy as those of females, consistent with stronger selection on male kidney mass. Previous studies have shown that male size enhances mating success in one-on-one competition prevalent in small mating aggregations. We then examined the relationship between body size, kidney mass and testes mass in two populations with low (LD) and high (HD) mating aggregation densities. Males from the HD population had heavier testes and heavier kidneys compared with males from the LD population; HD males were also smaller in body size. Our results suggest that the strength of sexual selection, and possibly the balance between pre- and postcopulatory selection, varies in response to population size or density. However, more replication is needed to confirm the generality of these results within red-sided garter snakes and other squamate reptiles.
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Affiliation(s)
- Christopher R Friesen
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Robert T Mason
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Emily J Uhrig
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
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7
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Friesen CR, Kahrl AF, Olsson M. Sperm competition in squamate reptiles. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200079. [PMID: 33070739 DOI: 10.1098/rstb.2020.0079] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Multiple paternity is ubiquitous within the polyphyletic group called 'reptiles', especially within the lizards and snakes. Therefore, the probability of sperm competition occurring, and being intense, is high. Squamates exhibit a diversity of tactics to ensure fertilization success in the face of sperm competition. The duration of female sperm storage, which can be many months and even years in some species, remains an enigma. Here, we emphasize some mechanisms that might affect patterns of paternity, the source and function of ejaculates and features of the female reproductive tract that may aid in long-term sperm storage. In doing so, we present a new analysis of the relationship between sperm size, the strength of sperm competition and the duration of female sperm storage. Lizards and snakes are a diverse group that has provided many excellent models for the study of an array of life-history strategies. However, when it comes to postcopulatory sexual selection, there is much left to discover. This article is part of the theme issue 'Fifty years of sperm competition'.
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Affiliation(s)
- Christopher R Friesen
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia.,Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Ariel F Kahrl
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Mats Olsson
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia.,Department of Biological and Environmental Science, University of Gothenburg, Goteborg, Sweden
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8
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Garlovsky MD, Yusuf LH, Ritchie MG, Snook RR. Within-population sperm competition intensity does not predict asymmetry in conpopulation sperm precedence. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200071. [PMID: 33070721 PMCID: PMC7661444 DOI: 10.1098/rstb.2020.0071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Postcopulatory sexual selection can generate evolutionary arms races between the sexes resulting in the rapid coevolution of reproductive phenotypes. As traits affecting fertilization success diverge between populations, postmating prezygotic (PMPZ) barriers to gene flow may evolve. Conspecific sperm precedence is a form of PMPZ isolation thought to evolve early during speciation yet has mostly been studied between species. Here, we show conpopulation sperm precedence (CpSP) between Drosophila montana populations. Using Pool-seq genomic data we estimate divergence times and ask whether PMPZ isolation evolved in the face of gene flow. We find models incorporating gene flow fit the data best indicating populations experienced considerable gene flow during divergence. We find CpSP is asymmetric and mirrors asymmetry in non-competitive PMPZ isolation, suggesting these phenomena have a shared mechanism. However, we show asymmetry is unrelated to the strength of postcopulatory sexual selection acting within populations. We tested whether overlapping foreign and coevolved ejaculates within the female reproductive tract altered fertilization success but found no effect. Our results show that neither time since divergence nor sperm competitiveness predicts the strength of PMPZ isolation. We suggest that instead cryptic female choice or mutation-order divergence may drive divergence of postcopulatory phenotypes resulting in PMPZ isolation. This article is part of the theme issue ‘Fifty years of sperm competition’.
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Affiliation(s)
- Martin D Garlovsky
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Leeban H Yusuf
- Centre for Biological Diversity, University of St Andrews, St Andrews KY16 9TH, UK
| | - Michael G Ritchie
- Centre for Biological Diversity, University of St Andrews, St Andrews KY16 9TH, UK
| | - Rhonda R Snook
- Department of Zoology, Stockholm University, Stockholm 106-91, Sweden
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9
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Rollings N, Waye HL, Krohmer RW, Uhrig EJ, Mason RT, Olsson M, Whittington CM, Friesen CR. Sperm telomere length correlates with blood telomeres and body size in red‐sided garter snakes,
Thamnophis sirtalis parietalis. J Zool (1987) 2020. [DOI: 10.1111/jzo.12789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- N. Rollings
- School of Life and Environmental Sciences University of Sydney Sydney NSW Australia
| | - H. L. Waye
- Division of Science and Mathematics University of Minnesota Morris Morris MN USA
| | - R. W Krohmer
- Department of Biological Sciences Saint Xavier University Chicago IL USA
| | - E. J. Uhrig
- Department of Integrative Biology Oregon State University Corvallis OR USA
| | - R. T. Mason
- Department of Integrative Biology Oregon State University Corvallis OR USA
| | - M. Olsson
- Department of Biological & Environmental Sciences University of Gothenburg Gothenburg Sweden
- School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong NSW Australia
| | - C. M. Whittington
- School of Life and Environmental Sciences University of Sydney Sydney NSW Australia
| | - C. R. Friesen
- School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong NSW Australia
- Illawarra Health and Medical Research Institute (IHMRI)University of Wollongong Wollongong NSW Australia
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10
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Kahrl AF, Johnson MA, Cox RM. Rapid evolution of testis size relative to sperm morphology suggests that post-copulatory selection targets sperm number in Anolis lizards. J Evol Biol 2019; 32:302-309. [PMID: 30659673 DOI: 10.1111/jeb.13414] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/14/2018] [Accepted: 01/14/2019] [Indexed: 11/28/2022]
Abstract
Post-copulatory sexual selection is thought to be responsible for much of the extraordinary diversity in sperm morphology across metazoans. However, the extent to which post-copulatory selection targets sperm morphology versus sperm production is generally unknown. To address this issue, we simultaneously characterized the evolution of sperm morphology (length of the sperm head, midpiece and flagellum) and testis size (a proxy for sperm production) across 26 species of Anolis lizards, a group in which sperm competition is likely. We found that the length of the sperm midpiece has evolved 2-3 times faster than that of the sperm head or flagellum, suggesting that midpiece size may be the most important aspect of sperm morphology with respect to post-copulatory sexual selection. However, testis size has evolved faster than any aspect of sperm morphology or body size, supporting the hypothesis that post-copulatory sexual selection acts more strongly upon sperm production than upon sperm morphology. Likewise, evolutionary increases in testis size, which typically indicate increased sperm competition, are not associated with predictable changes in sperm morphology, suggesting that any effects of post-copulatory selection on sperm morphology are either weak or variable in direction across anoles. Collectively, our results suggest that sperm production is the primary target of post-copulatory sexual selection in this lineage.
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Affiliation(s)
- Ariel F Kahrl
- Zoologiska institutionen: Etologi, Stockholm University, Stockholm, Sweden.,Department of Biology, University of Virginia, Charlottesville, Virginia
| | | | - Robert M Cox
- Department of Biology, University of Virginia, Charlottesville, Virginia
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11
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Rollings N, Uhrig EJ, Krohmer RW, Waye HL, Mason RT, Olsson M, Whittington CM, Friesen CR. Age-related sex differences in body condition and telomere dynamics of red-sided garter snakes. Proc Biol Sci 2018; 284:rspb.2016.2146. [PMID: 28381620 DOI: 10.1098/rspb.2016.2146] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 03/06/2017] [Indexed: 12/15/2022] Open
Abstract
Life-history strategies vary dramatically between the sexes, which may drive divergence in sex-specific senescence and mortality rates. Telomeres are tandem nucleotide repeats that protect the ends of chromosomes from erosion during cell division. Telomeres have been implicated in senescence and mortality because they tend to shorten with stress, growth and age. We investigated age-specific telomere length in female and male red-sided garter snakes, Thamnophis sirtalis parietalis We hypothesized that age-specific telomere length would differ between males and females given their divergent reproductive strategies. Male garter snakes emerge from hibernation with high levels of corticosterone, which facilitates energy mobilization to fuel mate-searching, courtship and mating behaviours during a two to four week aphagous breeding period at the den site. Conversely, females remain at the dens for only about 4 days and seem to invest more energy in growth and cellular maintenance, as they usually reproduce biennially. As male investment in reproduction involves a yearly bout of physiologically stressful activities, while females prioritize self-maintenance, we predicted male snakes would experience more age-specific telomere loss than females. We investigated this prediction using skeletochronology to determine the ages of individuals and qPCR to determine telomere length in a cross-sectional study. For both sexes, telomere length was positively related to body condition. Telomere length decreased with age in male garter snakes, but remained stable in female snakes. There was no correlation between telomere length and growth in either sex, suggesting that our results are a consequence of divergent selection on life histories of males and females. Different selection on the sexes may be the physiological consequence of the sexual dimorphism and mating system dynamics displayed by this species.
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Affiliation(s)
- Nicky Rollings
- School of Life and Environmental Sciences, University of Sydney, Heydon-Laurence Building (A08), New South Wales 2006, Australia
| | - Emily J Uhrig
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.,Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Randolph W Krohmer
- Department of Biological Sciences, Saint Xavier University, Chicago, IL, USA
| | - Heather L Waye
- Division of Science and Mathematics, University of Minnesota, Morris, MN, USA
| | - Robert T Mason
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Mats Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Camilla M Whittington
- School of Life and Environmental Sciences, University of Sydney, Heydon-Laurence Building (A08), New South Wales 2006, Australia.,Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, Australia
| | - Christopher R Friesen
- School of Life and Environmental Sciences, University of Sydney, Heydon-Laurence Building (A08), New South Wales 2006, Australia
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12
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Correlated evolution of sexually selected traits: interspecific variation in ejaculates, sperm morphology, copulatory mate guarding, and body size in two sympatric species of garter snakes. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2414-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Using whole-group metabolic rate and behaviour to assess the energetics of courtship in red-sided garter snakes. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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14
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15
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Hacking J, Stuart-Fox D, Gardner M. Very low rate of multiple paternity detected in clutches of a wild agamid lizard. AUST J ZOOL 2017. [DOI: 10.1071/zo18006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Genetic mating systems described for squamate reptiles range from primarily monogamous to completely polygynandrous. The presence of female multiple mating is almost ubiquitous among squamates and even occurs, albeit at a low rate, in socially monogamous species. Here we examine the genetic mating system of the territorial tawny dragon lizard (Ctenophorus decresii). Paternity was assigned to captive-born hatchlings using eight microsatellite loci, revealing a 4% rate of multiple paternity. One-quarter of males sired more than one clutch, although multiple mating by males is likely underestimated. The rate of multiple paternity in C. decresii represents one of the lowest among squamates and may be a result of successful male territoriality. However, the observed low rate of multiple paternity does not eliminate the possibility of widespread female multiple mating due to the potential for sperm storage and sperm competition. We conclude that the tawny dragon lizard employs a predominantly polygynous genetic mating system.
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16
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Friesen CR, Uhrig EJ, Mason RT, Brennan PLR. Female behaviour and the interaction of male and female genital traits mediate sperm transfer during mating. J Evol Biol 2016; 29:952-64. [PMID: 26809830 DOI: 10.1111/jeb.12836] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 01/18/2016] [Accepted: 01/19/2016] [Indexed: 02/04/2023]
Abstract
Natural selection and post-copulatory sexual selection, including sexual conflict, contribute to genital diversification. Fundamental first steps in understanding how these processes shape the evolution of specific genital traits are to determine their function experimentally and to understand the interactions between female and male genitalia during copulation. Our experimental manipulations of male and female genitalia in red-sided garter snakes (Thamnophis sirtalis parietalis) reveal that copulation duration and copulatory plug deposition, as well as total and oviductal/vaginal sperm counts, are influenced by the interaction between male and female genital traits and female behaviour during copulation. By mating females with anesthetized cloacae to males with spine-ablated hemipenes using a fully factorial design, we identified significant female-male copulatory trait interactions and found that females prevent sperm from entering their oviducts by contracting their vaginal pouch. Furthermore, these muscular contractions limit copulatory plug size, whereas the basal spine of the male hemipene aids in sperm and plug transfer. Our results are consistent with a role of sexual conflict in mating interactions and highlight the evolutionary importance of female resistance to reproductive outcomes.
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Affiliation(s)
- C R Friesen
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA.,School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, USA
| | - E J Uhrig
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - R T Mason
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - P L R Brennan
- Department of Biological Sciences, 104 Clapp Laboratory, Mount Holyoke College, South Hadley, MA, USA
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17
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Dayger CA, Lutterschmidt DI. Seasonal and sex differences in responsiveness to adrenocorticotropic hormone contribute to stress response plasticity in red-sided garter snakes (Thamnophis sirtalis parietalis). J Exp Biol 2016; 219:1022-30. [DOI: 10.1242/jeb.130450] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 01/20/2016] [Indexed: 11/20/2022]
Abstract
Like many vertebrates, hormonal responses to stress vary seasonally in red-sided garter snakes (Thamnophis sirtalis parietalis). For example, males generally exhibit reduced glucocorticoid responses to a standard stressor during the spring mating season. We asked whether variation in adrenal sensitivity to adrenocorticotropic hormone (ACTH) explains why glucocorticoid responses to capture stress vary with sex, season, and body condition in red-sided garter snakes. We measured glucocorticoids at 0, 1, and 4 hours after injection with ACTH (0.1 IU/g body mass) or vehicle in males and females during the spring mating season and fall pre-hibernation period. Because elevated glucocorticoids can influence sex steroids, we also examined androgen and estradiol responses to ACTH. ACTH treatment increased glucocorticoids in both sexes and seasons. Spring-collected males had a smaller integrated glucocorticoid response to ACTH than fall-collected males. The integrated glucocorticoid response to ACTH differed with sex during the spring, with males having a smaller glucocorticoid response than females. Although integrated glucocorticoid responses to ACTH did not vary with body condition, we observed an interaction among season, sex and body condition. In males, ACTH treatment did not alter androgens in either season, but androgens decreased during the sampling period. Similar to previous studies, plasma estradiol was low or undetectable during the spring and fall and therefore any effect of ACTH treatment on estradiol could not be determined. These data provide support for a mechanism that partly explains how the HPA axis integrates information about season, sex, and body condition: namely, variation in adrenal responsiveness to ACTH.
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Affiliation(s)
- Catherine A. Dayger
- Portland State University, Department of Biology, 1719 SW 10th Ave, Portland, OR 97201, USA
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Le Y, Chen S, Hu L, Zhang L, Ullah S, Liu T, Yang P, Liu Y, Chen Q. B-cell lymphoma-2 localization in the female reproductive tract of the Chinese soft-shelled turtle, Pelodiscus sinensis and its relationship with sperm storage. Anat Rec (Hoboken) 2015; 298:2011-7. [PMID: 26285642 DOI: 10.1002/ar.23258] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/11/2015] [Accepted: 06/20/2015] [Indexed: 01/20/2023]
Abstract
The aim of the present study was to investigate the expression and localization of B-cell lymphoma-2 (Bcl-2) in the oviduct of the Chinese soft-shelled turtle, Pelodiscus sinensis, during the reproductive cycle to analyze the relationship between Bcl-2 and sperm storage. Bcl-2 expression was confirmed in the P. sinensis oviduct by western blot analysis. Hematoxylin-eosin staining showed that female P. sinensis stored sperm from November to April of the following year. The oviduct showed positive immunostaining for Bcl-2 of epithelial ciliated cells, gland ducts, and gland cells. Bcl-2 expression in the oviduct was associated with sperm storage occurrence. This indicates that the survival factor Bcl-2 may play a role in P. sinensis sperm storage.
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Affiliation(s)
- Yuan Le
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Shaofan Chen
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Lisi Hu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Linli Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Shakeeb Ullah
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Tengfei Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Ping Yang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Yi Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Qiusheng Chen
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People's Republic of China
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Friesen CR, Powers DR, Copenhaver PE, Mason RT. Size dependence in non-sperm ejaculate production is reflected in daily energy expenditure and resting metabolic rate. J Exp Biol 2015; 218:1410-8. [DOI: 10.1242/jeb.120402] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
ABSTRACT
The non-sperm components of an ejaculate, such as copulatory plugs, can be essential to male reproductive success. But the costs of these ejaculate components are often considered trivial. In polyandrous species, males are predicted to increase energy allocation to the production of non-sperm components, but this allocation is often condition dependent and the energetic costs of their production have never been quantified. Red-sided garter snakes (Thamnophis sirtalis parietalis) are an excellent model with which to quantify the energetic costs of non-sperm components of the ejaculate as they exhibit a dissociated reproductive pattern in which sperm production is temporally disjunct from copulatory plug production, mating and plug deposition. We estimated the daily energy expenditure and resting metabolic rate of males after courtship and mating, and used bomb calorimetry to estimate the energy content of copulatory plugs. We found that both daily energy expenditure and resting metabolic rate were significantly higher in small mating males than in courting males, and a single copulatory plug without sperm constitutes 5–18% of daily energy expenditure. To our knowledge, this is the first study to quantify the energetic expense of size-dependent ejaculate strategies in any species.
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Affiliation(s)
- Christopher R. Friesen
- School of Biological Sciences, University of Sydney, Heydon-Laurence Bldg AO8, Science Rd, Sydney, NSW 2006, Australia
- Department of Zoology, Oregon State University, Cordley Hall 3029, Corvallis, OR 97330, USA
| | - Donald R. Powers
- Department of Biology, George Fox University, Edwards-Holman Science Center, Newberg, OR 97132, USA
| | - Paige E. Copenhaver
- Department of Biology, George Fox University, Edwards-Holman Science Center, Newberg, OR 97132, USA
- Department of Botany and Program in Ecology, University of Wyoming, Aven Nelson Building 130, Laramie, WY 82071, USA
| | - Robert T. Mason
- Department of Zoology, Oregon State University, Cordley Hall 3029, Corvallis, OR 97330, USA
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Friesen CR, Uhrig EJ, Mason RT. Females remate more frequently when mated with sperm-deficient males. ACTA ACUST UNITED AC 2014; 321:603-9. [PMID: 25366702 DOI: 10.1002/jez.1892] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/21/2014] [Accepted: 08/22/2014] [Indexed: 01/31/2023]
Abstract
Polyandry is a source of sexual conflict and males often try to limit female promiscuity. Consequently, male manipulation of receptivity via antiaphrodisiacs and copulatory plugs that prevent female remating can be a source of sexual conflict. This sexual conflict may be intensified when females must remate for fertility insurance. Male red-sided garter snakes produce a large, gelatinous copulatory plug that has been proposed to 1) physically prevent remating and 2) contain an antiaphrodisiac that reduces female receptivity. These males may become sperm depleted because of their dissociated reproductive pattern. If a female mates with a sperm deficient male and is also rendered unreceptive to further mating, then this represents a serious conflict. We tested whether female remating frequency is affected when females are mated with a male that produces a sperm-less copulatory plug. We show that females are significantly more likely to remate after mating with vasectomized males than intact males, even though vasectomized males still produce a copulatory plug. These results suggest that the ejaculate material of the plug does not contain an antiaphrodisiac. Instead, females may use sperm as a cue for post-copulatory mate assessment and seek to remate for the direct benefit of fertility insurance if they have mated with sperm-depleted males.
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Affiliation(s)
- Christopher R Friesen
- School of Biological Sciences, University of Sydney, Sydney, Australia; Department of Integrative Biology, Oregon State University, Corvallis, Oregon
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Friesen CR, Kerns AR, Mason RT. Factors influencing paternity in multiply mated female red-sided garter snakes and the persistent use of sperm stored over winter. Behav Ecol Sociobiol 2014. [DOI: 10.1007/s00265-014-1749-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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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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